Sep. 2019, Geologiocal Society of Japan, Paper Award　　　　　　　　　　　　　　　
Hitoshi Hasegawa, Hisao Ando, Noriko Hasebe, Niiden Ichinnorov, Tohru Ohta, Takashi Hasegawa, Masanobu Yamamoto, Gang Li, Bat‐Orshikh Erdenetsogt, Ulrich Heimhofer, Takayuki Murata, Hironori Shinya, G. Enerel, G. Oyunjargal, O. Munkhtsetseg, Noriyuki Suzu
YAMAMOTO Masanobu

Jul. 2016, 日本有機地球化学会, 2016年度有機地球化学賞（学術賞）受賞　　　　　　　　　　　　　　　
バイオマーカーによる古海洋環境の復元に関する研究
山本 正伸

Nov. 2015, 地球環境史学会, 2014年度地球環境史学会貢献賞　　　　　　　　　　　　　　　
後期第四紀の北太平洋亜熱帯循環変動に関する研究
山本 正伸

Feb. 1999, 地質調査所, 地質調査所月報賞　　　　　　　　　　　　　　　
Yamamoto, M., Bat-erdene, D., Ulziikhishig, P., Watanabe, Y., Imai, N., Kajiwara, Y., Takeda, N., Nakajima, T. (1998) Organic geochemistry and palynology of Lower Cretaceous Zuunbayan oil shales, Mongolia, Bull. Geol. Surv. Japan, 49, 6, 257-274.
山本 正伸

Jul. 1997, 有機地球化学研究会, 研究奨励賞（田口賞）受賞　　　　　　　　　　　　　　　
アザーレン組成に基づく石油移動の有機地球化学的研究
山本 正伸

Rapid Holocene deposition in the Mackenzie Trough and Barrow Canyon areas in the western Arctic Ocean
Masanobu Yamamoto, Kenta Suzuki, Masafumi Murayama, Laura Gemery, Koji Seike, Leonid Polyak, Young Jin Joe, Shoma Uchida, Minoru Kobayashi, Jonaotaro Onodera, Keiji Horikawa, Yuhji Yamamoto, Takayuki Omori, Michinobu Kuwae, Tomohisa Irino, Yutaka Y. Watanabe, Motoyo Itoh, Eiji Watanabe
Progress in Earth and Planetary Science, 28 Jul. 2025
Scientific journal

Seasonal Sea Surface Temperature Variations at the Northern Limit of the Kuroshio Current in Marine Isotope Stage 20–18
Hiroto Kajita, Yusuke Suganuma, Yuki Haneda, Makoto Okada, Masanobu Yamamoto, Osamu Seki, Naohiko Ohkouchi
Geophysical Research Letters, 52, 3, American Geophysical Union (AGU), 16 Feb. 2025
Scientific journal, Abstract

This study presents a high time‐resolution alkenone unsaturation ratios (U^K'₃₇) in the Chiba composite section, a marine sedimentary sequence formed in the Kazusa forearc basin in the northwestern Pacific under the influence of the Kuroshio and Oyashio currents. The U^K'₃₇ reflects summer sea surface temperature (SST) and records glacial‐interglacial to sub‐millennial‐scale variations spanning the marine isotope stage (MIS) 19, an analog of our Holocene interglacial. At the glacial‐interglacial scale, summer U^K'₃₇‐SST and previously published winter SST fluctuations are in tandem with East Asian Summer and Winter monsoon variabilities, respectively. Millennial‐scale U^K'₃₇‐SST variations correspond to meltwater events in the North Atlantic. Summer temperature amplitudes maybe half those in winter, suggesting the stable dominance of the Kuroshio Current during the summer and significant winter cooling caused by the Oyashio Current intrusion. Our study reveals the unique seasonally different atmosphere‐ocean coupling system during MIS 19 at the subarctic front in the northwestern Pacific.

Replicability of paleotemperature records in the northern Okinawa Trough and its implications for paleoceanographic reconstructions
Ru-Yun Tung, Sze Ling Ho, Yoshimi Kubota, Masanobu Yamamoto, Jens Hefter, Chuan-Chou Shen
Progress in Earth and Planetary Science, 11, 1, Springer Science and Business Media LLC, 25 Nov. 2024
Scientific journal, Abstract

Geochemical proxies are frequently utilized in the reconstruction of past ocean temperatures. Due to resource constraints, these reconstructions typically rely on a single sediment core, raising questions about the local and regional representativeness of paleotemperature records. To address this, we analyzed four sediment cores located within a 10-km radius in the northern Okinawa Trough (OT), which share the same climatic forcing and thus should reflect similar climate variations. We compiled published data and generated new paleotemperature estimates based on three widely used geochemical proxies (foraminiferal Mg/Ca, $${\text{U } }_{37}^{ { {\text{K } }^{\prime } } }$$, $${\text{TEX } }_{86}$$). Analysis of the mean absolute deviations for nearby records based on the same proxy revealed that $${\text{U } }_{37}^{ { {\text{K } }^{\prime } } }$$ has the highest reproducibility, followed by Mg/Ca and $${\text{TEX } }_{86}$$. However, inconsistencies in inter-proxy offsets among nearby sites suggest the presence of noise in the proxy records, likely stemming from instrumental errors and sediment heterogeneity. Furthermore, the Mg/Ca and $${\text{U } }_{37}^{ { {\text{K } }^{\prime } } }$$ paleotemperature records agree within uncertainty when accounting for inter-site variability and calibration uncertainties, challenging previous interpretations of temperature signals from different seasons. All proxies indicate similar glacial-interglacial trends, albeit with varying magnitudes of temperature change. Both Mg/Ca and $${\text{U } }_{37}^{ { {\text{K } }^{\prime } } }$$ records suggest a glacial cooling of ~ 3 °C, whereas $${\text{TEX } }_{86}$$ sea surface temperature (SST) data indicate a stronger glacial cooling of approximately ~ 6–8 °C. Modern observations indicate a subsurface $${\text{TEX } }_{86}$$ recording depth of 50–100 m, coinciding with the thermocline. However, the $${\text{TEX } }_{86}$$ subsurface temperature (subT) record does not resemble the Mg/Ca records of thermocline-dwelling foraminifera species. Instead, there is a better agreement with benthic foraminiferal Mg/Ca records of Uvigerina spp. (~ 700 m) and the intermediate temperature record derived from radiolarian assemblages (~ 500 m), pointing to a $${\text{TEX } }_{86}$$ recording depth that is deeper than the thermocline. In summary, our findings show that proxy noise can impact inter-proxy comparisons of paleotemperature records, but not the direction of glacial-interglacial shifts. Future research should prioritize constraining the recording depth of paleotemperature proxies and reducing calibration uncertainty for more precise and reliable quantitative paleotemperature reconstruction.

Spatially variable response of Antarctica's ice sheets to orbital forcing during the Pliocene
Molly Patterson, Christiana Rosenberg, Osamu Seki, Masanobu Yamamoto, Oscar Romero, Mei Nelissen, Francesca Sangiorgi, Nick Golledge, Georgia Grant, William Arnuk, Benjamin Keisling, Tim Naish, Richard Levy, Stephen Meyers, Nicholas Sullivan, Jeanine Ash, Denise Kulhanek, Brian Romans, Natalia Varela, Harold Jones, François Beny, Imogene Browne, Giuseppe Cortese, Isabela Cordeiro de Sousa, Justin Dodd, Oliver Esper, Jenny Gales, David Harwood, Saki Ishino, Sookwan Kim, Sunghan Kim, Jan Sverre Laberg, R. Leckie, J. Müller, Amelia Shevenell, Shiv Singh, Saiko Sugisaki, Tina van de Flierdt, Tim van Peer, Wenshen Xiao, Laura De Santis, Robert McKay
05 Sep. 2024

Interlaboratory Comparison of Branched GDGT Temperature and pH Proxies Using Soils and Lipid Extracts
Cindy De Jonge, Francien Peterse, Klaas G. J. Nierop, Thomas M. Blattmann, Marcelo Alexandre, Salome Ansanay‐Alex, Thomas Austin, Mathieu Babin, Edouard Bard, Thorsten Bauersachs, Jerome Blewett, Brenna Boehman, Isla S. Castañeda, Junhui Chen, Martina L. G. Conti, Sergio Contreras, Julia Cordes, Nina Davtian, Bart van Dongen, Bella Duncan, Felix J. Elling, Valier Galy, Shaopeng Gao, Jens Hefter, Kai‐Uwe Hinrichs, Mitchell R. Helling, Mariska Hoorweg, Ellen Hopmans, Juzhi Hou, Yongsong Huang, Arnaud Huguet, Guodong Jia, Cornelia Karger, Brendan J. Keely, Stephanie Kusch, Hui Li, Jie Liang, Julius S. Lipp, Weiguo Liu, Hongxuan Lu, Kai Mangelsdorf, Hayley Manners, Alfredo Martinez Garcia, Guillemette Menot, Gesine Mollenhauer, B. David A. Naafs, Sebastian Naeher, Lauren K. O'Connor, Ethan M. Pearce, Ann Pearson, Zhiguo Rao
Geochemistry, Geophysics, Geosystems, Jul. 2024
English, Scientific journal, AbstractRatios of glycerol dialkyl glycerol tetraethers (GDGT), which are membrane lipids of bacteria and archaea, are at the base of several paleoenvironmental proxies. They are frequently applied to soils as well as lake‐ and marine sediments to generate records of past temperature and soil pH. To derive meaningful environmental information from these reconstructions, high analytical reproducibility is required. Based on submitted results by 39 laboratories from across the world, which employ a diverse range of analytical and quantification methods, we explored the reproducibility of brGDGT‐based proxies (MBT′5ME, IR, and #ringstetra) measured on four soil samples and four soil lipid extracts. Correct identification and integration of 5‐ and 6‐methyl brGDGTs is a prerequisite for the robust calculation of proxy values, but this can be challenging as indicated by the large inter‐interlaboratory variation. The exclusion of statistical outliers improves the reproducibility, where the remaining uncertainty translates into a temperature offset from median proxy values of 0.3–0.9°C and a pH offset of 0.05–0.3. There is no apparent systematic impact of the extraction method and sample preparation steps on the brGDGT ratios. Although reported GDGT concentrations are generally consistent within laboratories, they vary greatly between laboratories. This large variability in brGDGT quantification may relate to variations in ionization efficiency or specific mass spectrometer settings possibly impacting the response of brGDGTs masses relative to that of the internal standard used. While ratio values of GDGT are generally comparable, quantities can currently not be compared between laboratories.

History of the terrestrial isopod genus Ligidium in Japan based on phylogeographic analysis
Wakana Harigai, Aya Saito, Chika Zemmoto, Shigenori Karasawa, Touta Yokoi, Atsushi J. Nagano, Hitoshi Suzuki, Masanobu Yamamoto
BMC Ecology and Evolution, 23, 1, Springer Science and Business Media LLC, 07 Aug. 2023
Scientific journal, Abstract

Background

Phylogeographical approaches explain the genetic diversity of local organisms in the context of their geological and geographic environments. Thus, genetic diversity can be a proxy for geological history. Here we propose a genus of woodland isopod, Ligidium, as a marker of geological history in relation to orogeny and the Quaternary glacial cycle.

Results

Mitochondrial analysis of 721 individuals from 97 sites across Japan revealed phylogenetic divergence between the northeastern and southwestern Japan arcs. It also showed repeated population expansions in northeastern Japan in response to Quaternary glacial and interglacial cycles. Genome-wide analysis of 83 selected individuals revealed multiple genetic nuclear clusters. The genomic groupings were consistent with the local geographic distribution, indicating that the Ligidium phylogeny reflects its regional history.

Conclusion

Ligidium DNA sequence analysis can provide insight into the geological, geographical, and paleoenvironmental history of the studied region.

Multiple episodes of ice loss from the Wilkes Subglacial Basin during the Last Interglacial
Mutsumi Iizuka, Osamu Seki, David J. Wilson, Yusuke Suganuma, Keiji Horikawa, Tina van de Flierdt, Minoru Ikehara, Takuya Itaki, Tomohisa Irino, Masanobu Yamamoto, Motohiro Hirabayashi, Hiroyuki Matsuzaki, Saiko Sugisaki
Nature Communications, 14, 1, Springer Science and Business Media LLC, 18 Apr. 2023
Scientific journal, Abstract

The Last Interglacial (LIG: 130,000–115,000 years ago) was a period of warmer global mean temperatures and higher and more variable sea levels than the Holocene (11,700–0 years ago). Therefore, a better understanding of Antarctic ice-sheet dynamics during this interval would provide valuable insights for projecting sea-level change in future warming scenarios. Here we present a high-resolution record constraining ice-sheet changes in the Wilkes Subglacial Basin (WSB) of East Antarctica during the LIG, based on analysis of sediment provenance and an ice melt proxy in a marine sediment core retrieved from the Wilkes Land margin. Our sedimentary records, together with existing ice-core records, reveal dynamic fluctuations of the ice sheet in the WSB, with thinning, melting, and potentially retreat leading to ice loss during both early and late stages of the LIG. We suggest that such changes along the East Antarctic Ice Sheet margin may have contributed to fluctuating global sea levels during the LIG.

Beppu Bay, Japan, as a candidate Global Boundaries Stratotype Section and Point for an Anthropocene series
Michinobu Kuwae, Bruce P Finney, Zhiyuan Shi, Aya Sakaguchi, Narumi Tsugeki, Takayuki Omori, Tetsuro Agusa, Yoshiaki Suzuki, Yusuke Yokoyama, Hirofumi Hinata, Yoshio Hatada, Jun Inoue, Kazumi Matsuoka, Misaki Shimada, Hikaru Takahara, Shin Takahashi, Daisuke Ueno, Atsuko Amano, Jun Tsutsumi, Masanobu Yamamoto, Keiji Takemura, Keitaro Yamada, Ken Ikehara, Tsuyoshi Haraguchi, Stephen Tims, Michaela Froehlich, Leslie Keith Fifield, Takahiro Aze, Kimikazu Sasa, Tsutomu Takahashi, Masumi Matsumura, Yukinori Tani, Peter R Leavitt, Hideyuki Doi, Tomohisa Irino, Kazuyoshi Moriya, Akira Hayashida, Kotaro Hirose, Hidekazu Suzuki, Yoshiki Saito
The Anthropocene Review, 205301962211350, 205301962211350, SAGE Publications, 19 Dec. 2022
Scientific journal, For assessment of the potential of the Beppu Bay sediments as a Global Boundaries Stratotype Section and Point (GSSP) candidate for the Anthropocene, we have integrated datasets of 99 proxies. The datasets for the sequences date back 100 years for most proxy records and 1300 years for several records. The cumulative number of occurrences of the anthropogenic fingerprint reveal unprecedented increases above the base of the 1953 flood layer at 64.6 cm (1953 CE), which coincides with an initial increase in global fallout of ²³⁹Pu+²⁴⁰Pu. The onset of the proliferation of anthropogenic fingerprints was followed by diverse human-associated events, including a rapid increase in percent modern ¹⁴C in anchovy scales, changes in nitrogen and carbon cycling as recorded by anchovy δ¹⁵N and δ¹³C, elevated pollution of heavy metals, increased depositions of novel materials (spheroidal carbonaceous particles, microplastics, polychlorinated biphenyls), the occurrence of hypoxia (Re/Mo ratio) and eutrophication (biogenic opal, TOC, TN, diatoms, chlorophyll a), unprecedented microplankton community changes (compositions of carotenoids, diatoms, dinoflagellates), abnormally high spring air temperatures as inferred from diatom fossils, and lithological changes. These lines of evidence indicate that the base of the 1953 layer is the best GSSP level candidate in the stratigraphy at this site.

Decadal–centennial-scale solar-linked climate variations and millennial-scale internal oscillations during the Early Cretaceous
Hitoshi Hasegawa, Nagayoshi Katsuta, Yasushi Muraki, Ulrich Heimhofer, Niiden Ichinnorov, Hirofumi Asahi, Hisao Ando, Koshi Yamamoto, Masafumi Murayama, Tohru Ohta, Masanobu Yamamoto, Masayuki Ikeda, Kohki Ishikawa, Ryusei Kuma, Takashi Hasegawa, Noriko Hasebe, Shoji Nishimoto, Koichi Yamaguchi, Fumio Abe, Ryuji Tada, Takeshi Nakagawa
Scientific Reports, 12, 1, Springer Science and Business Media LLC, 19 Dec. 2022
Scientific journal, Abstract

Understanding climate variability and stability under extremely warm ‘greenhouse’ conditions in the past is essential for future climate predictions. However, information on millennial-scale (and shorter) climate variability during such periods is scarce, owing to a lack of suitable high-resolution, deep-time archives. Here we present a continuous record of decadal- to orbital-scale continental climate variability from annually laminated lacustrine deposits formed during the late Early Cretaceous (123–120 Ma: late Barremian–early Aptian) in southeastern Mongolia. Inter-annual changes in lake algal productivity for a 1091-year interval reveal a pronounced solar influence on decadal- to centennial-scale climatic variations (including the ~ 11-year Schwabe cycle). Decadally-resolved Ca/Ti ratios (proxy for evaporation/precipitation changes) for a ~ 355-kyr long interval further indicate millennial-scale (~ 1000–2000-yr) extreme drought events in inner-continental areas of mid-latitude palaeo-Asia during the Cretaceous. Millennial-scale oscillations in Ca/Ti ratio show distinct amplitude modulation (AM) induced by the precession, obliquity and short eccentricity cycles. Similar millennial-scale AM by Milankovitch cycle band was also previously observed in the abrupt climatic oscillations (known as Dansgaard–Oeschger events) in the ‘intermediate glacial’ state of the late Pleistocene, and in their potential analogues in the Jurassic ‘greenhouse’. Our findings indicate that external solar activity forcing was effective on decadal–centennial timescales, whilst the millennial-scale variations were likely amplified by internal process such as changes in deep-water formation strength, even during the Cretaceous ‘greenhouse’ period.

Environmental evolution and fire history of Rebun Island (Northern Japan) during the past 17,000 years based on biomarkers and pyrogenic compound records from Lake Kushu
Masanobu Yamamoto, Fangxian Wang, Tomohisa Irino, Kazuyoshi Yamada, Tsuyoshi Haraguchi, Hideto Nakamura, Katsuya Gotanda, Hitoshi Yonenobu, Christian Leipe, Xuan-Yu Chen, Pavel E. Tarasov
QUATERNARY INTERNATIONAL, 623, 8, 18, Jun. 2022
English, Scientific journal

Reconstruction of the eukaryotic communities in Beppu Bay over the past 50 years based on sedimentary DNA barcoding
Yudai Segawa, Masanobu Yamamoto, Michinobu Kuwae, Kazuyoshi Moriya, Hitoshi Suzuki, Koji Suzuki
Journal of Geophysical Research: Biogeosciences, 127, 6, American Geophysical Union (AGU), 27 May 2022
Scientific journal

Increased interglacial atmospheric CO2 levels followed the mid-Pleistocene Transition
Masanobu Yamamoto, Steven C. Clemens, Osamu Seki, Yuko Tsuchiya, Yongsong Huang, Ryouta O'ishi, Ayako Abe-Ouchi
NATURE GEOSCIENCE, 15, 4, 307, +, Apr. 2022, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

Impact of Climate Change on Hunter-Fisher-Gatherer Cultures in Northern Japan Over the Past 4,400 Years
Masanobu Yamamoto, Osamu Seki
GEOPHYSICAL RESEARCH LETTERS, 49, 5, Mar. 2022, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

New radiocarbon estimation method for carbonate-poor sediments: A case study of ramped pyrolysis ¹⁴C dating of postglacial deposits from the Alaskan margin, Arctic Ocean
Kenta Suzuki, Masanobu Yamamoto, Brad E. Rosenheim, Takayuki Omori, Leonid Polyak
Quaternary Geochronology, 66, Oct. 2021
Scientific journal

Tropical Western Pacific Hydrology During the Last 6,000 Years Based on Wildfire Charcoal Records From Borneo
Masanobu Yamamoto, Takafumi Kikuchi, Hiromichi Sakurai, Ryoma Hayashi, Osamu Seki, Takayuki Omori, Abdullah Sulaiman, Hasrizal Shaari, Mohd Zulhilmy Abdullah, Lulie Melling
Geophysical Research Letters, 48, 18, 28 Sep. 2021, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

Cellulose Oxygen Isotopes of Sphagnum and Vascular Plants in a Peat Core Reveal Climate Change in Northern Japan Over the Past 2,000 Years
Hiromichi Sakurai, Masanobu Yamamoto, Osamu Seki, Takayuki Omori, Tomonori Sato
Geochemistry, Geophysics, Geosystems, 22, 9, 28 Sep. 2021, [Peer-reviewed], [Corresponding author]
English, Scientific journal

The significance of pyrogenic polycyclic aromatic hydrocarbons in Borneo peat core for the reconstruction of fire history
Sher-Rine Kong, Masanobu Yamamoto, Hasrizal Shaari, Ryoma Hayashi, Osamu Seki, Norhayati Mohd Tahir, Muhammad Fais Fadzil, Abdullah Sulaiman
PLOS ONE, 16, 9, e0256853, e0256853, Public Library of Science (PLoS), 08 Sep. 2021, [Peer-reviewed], [Corresponding author]
Scientific journal, The reconstruction of fire history is essential to understand the palaeoclimate and human history. Polycyclic aromatic hydrocarbons (PAHs) have been extensively used as a fire marker. In this work, the distribution of PAHs in Borneo peat archives was investigated to understand how PAHs reflect the palaeo-fire activity. In total, 52 peat samples were analysed from a Borneo peat core for the PAH analysis. Pyrogenic PAHs consist of 2–7 aromatic rings, some of which have methyl and ethyl groups. The results reveal that the concentration of pyrogenic PAHs fluctuated with the core depth. Compared to low-molecular-weight (LMW) PAHs, the high-molecular-weight (HMW) PAHs had a more similar depth variation to the charcoal abundance. This finding also suggests that the HMW PAHs were mainly formed at a local fire near the study area, while the LMW PAHs could be transported from remote locations.

Linking historical vegetation to bacterial succession under the contrasting climates of the Tibetan Plateau
Haijun Yuan, Fanfan Meng, Masanobu Yamamoto, Xingqi Liu, Hailiang Dong, Ji Shen, Huaqun Yin, Jianjun Wang
ECOLOGICAL INDICATORS, 126, Jul. 2021, [Peer-reviewed]
English, Scientific journal

A Lacustrine Biomarker Record From Rebun Island Reveals a Warm Summer Climate in Northern Japan During the Early Middle Holocene Due to a Stronger North Pacific High
Masanobu Yamamoto, Fangxian Wang, Tomohisa Irino, Kenta Suzuki, Kazuyoshi Yamada, Tsuyoshi Haraguchi, Katsuya Gotanda, Hitoshi Yonenobu, Xuan-Yu Chen, Pavel Tarasov
FRONTIERS IN EARTH SCIENCE, 9, Jun. 2021, [Peer-reviewed], [Invited], [Lead author, Corresponding author]
English, Scientific journal

Remote and local drivers of Pleistocene South Asian summer monsoon precipitation: A test for future predictions
Steven C. Clemens, Masanobu Yamamoto, Kaustubh Thirumalai, Liviu Giosan, Julie N. Richey, Katrina Nilsson-Kerr, Yair Rosenthal, Pallavi Anand, Sarah M. McGrath
Science Advances, 7, 23, Jun. 2021, [Peer-reviewed]
English, Scientific journal

Greenhouse Gas and Ice Volume Drive Pleistocene Indian Summer Monsoon Precipitation Isotope Variability
Sarah M. McGrath, Steven C. Clemens, Yongsong Huang, Masanobu Yamamoto
Geophysical Research Letters, 48, 4, 28 Feb. 2021, [Peer-reviewed]
English, Scientific journal

Genetic Diversity of Ligidium Isopods in Hokkaido and Niigata, Northern Japan, Based on Mitochondrial DNA Analysis
Wakana Harigai, Aya Saito, Hitoshi Suzuki, Masanobu Yamamoto
ZOOLOGICAL SCIENCE, 37, 5, 417, 428, Oct. 2020, [Peer-reviewed], [Last author]
English, Scientific journal

Late Miocene changes in C3, C4 and aquatic plant vegetation in the Indus River basin: evidence from leaf wax δ13C from Indus Fan sediments
Kenta Suzuki, Masanobu Yamamoto, Osamu Seki
Geological Magazine, 157, 6, 979, 988, Jun. 2020, [Peer-reviewed], [Corresponding author]
English, Scientific journal

Application of laser-induced breakdown spectroscopy to Arctic sediments in the Chukchi Sea
Dukki Han, Young Jin Joe, Jong-Sik Ryu, Tatsuya Unno, Gibaek Kim, Masanobu Yamamoto, Kihong Park, Hor-Gil Hur, Ji-Hoon Lee, Seung-Il Nam
Spectrochimica Acta - Part B Atomic Spectroscopy, 146, 84, 92, 01 Aug. 2018, [Peer-reviewed]
English, Scientific journal

Holocene surface hydroclimate changes in the Indo-Pacific warm pool
Ziye Li, Min-Te Chen, Da-Cheng Lin, Houjie Wang, Xuefa Shi, Shengfa Liu, Yusuke Yokoyama, Masanobu Yamamoto, Chuan-Chou Shen, Horng-Sheng Mii, Rainer Arief Troa, Rina Zuraida, Eko Triarso, Marfasran Hendrizan
Quaternary International, 482, 1, 12, 20 Jul. 2018, [Peer-reviewed]
English, Scientific journal

Depositional ages and characteristics of Middle–Upper Jurassic and Lower Cretaceous lacustrine deposits in southeastern Mongolia
Hitoshi Hasegawa, Hisao Ando, Noriko Hasebe, Niiden Ichinnorov, Tohru Ohta, Takashi Hasegawa, Masanobu Yamamoto, Gang Li, Bat-Orshikh Erdenetsogt, Ulrich Heimhofer, Takayuki Murata, Hironori Shinya, G. Enerel, G. Oyunjargal, O. Munkhtsetseg, Noriyuki Suzuki, Tomohisa Irino, Koshi Yamamoto
Island Arc, 27, 3, 01 May 2018, [Peer-reviewed]
English, Scientific journal

Phylogenetic diversity and distribution of bacterial and archaeal amoA genes in the East China Sea during spring
Takafumi Kataoka, Koji Suzuki, Tomohisa Irino, Masanobu Yamamoto, Seigo Higashi, Hongbin Liu
Archives of Microbiology, 200, 2, 329, 342, 01 Mar. 2018, [Peer-reviewed]
English, Scientific journal

A deep-sea agglutinated foraminifer tube constructed with planktonic foraminifer shells of a single species
Paul N. Pearson, IODP Expedition 363 Shipboard Scientific Party, Ivano W. Aiello, Tali L. Babila, Germain Bayon, Luc Beaufort, Samantha C. Bova, Jong-Hwa Chun, Haowen Dang, Anna Joy Drury, Tom Dunkley Jones, Patrícia P.B. Eichler, Fernando Allan Gil Salazar, Kelly Gibson, Robert G. Hatfield, Ann E. Holbourn, Daniel L. Johnson, Denise K. Kulhanek, Yuho Kumagai, Tiegang Li, Braddock K. Linsley, Niklas Meinicke, Gregory S. Mountain, Bradley N. Opdyke, Christopher R. Poole, Christina Ravelo, Yair Rosenthal, Takuya Sagawa, Anaïs Schmitt, Jennifer B. Wurtzel, Jian Xu, Masanobu Yamamoto, Yi Ge Zhang
Journal of Micropalaeontology, 37, 1, 97, 104, Geological Society of London, 05 Jan. 2018, [Peer-reviewed]
English, Scientific journal

Climatic and ecological changes of the past 1900 years inferred from long-chain alkenones in Kusai Lake, northern Qinghai-Tibetan Plateau
Xudong Wu, Xingqi Liu, Jianjun Wang, Masanobu Yamamoto
Quaternary International, 487, 33, 42, 2018, [Peer-reviewed], [Last author]
English, Scientific journal

Multidecadal, centennial, and millennial variability in sardine and anchovy abundances in the western North Pacific and climate-fish linkages during the late Holocene
Michinobu Kuwae, Masanobu Yamamoto, Takuya Sagawa, Ken Ikehara, Tomohisa Irino, Keiji Takemura, Hidetaka Takeoka, Takashige Sugimoto
PROGRESS IN OCEANOGRAPHY, 159, 86, 98, Dec. 2017, [Peer-reviewed]
English, Scientific journal

Hydrographic variability in the northern South China Sea over the past 45,000 years: New insights based on temperature reconstructions by U-37(k ') and TEX86H proxies from a marine sediment core (MD972146)
Da-Cheng Lin, Min-Te Chen, Masanobu Yamamoto, Yusuke Yokoyama
QUATERNARY INTERNATIONAL, 459, 1, 16, Nov. 2017, [Peer-reviewed]
English, Scientific journal

Glycerol dialkyl glycerol tetraethers in the Ohno River estuary, Japan during the Holocene
Masanobu Yamamoto, Yasuto Yamamoto, Keiji Takemura
QUATERNARY INTERNATIONAL, 452, 129, 136, Sep. 2017, [Peer-reviewed], [Lead author]
English, Scientific journal

Revised ages of late Holocene tephras in Beppu Bay, central Kyushu, southwest Japan
Keitaro Yamada, Keiji Takemura, Michinobu Kuwae, Masanobu Yamamoto, Tohru Danhara
QUATERNARY INTERNATIONAL, 452, 33, 42, Sep. 2017, [Peer-reviewed]
English, Scientific journal

Holocene dynamics in the Bering Strait inflow to the Arctic and the Beaufort Gyre circulation based on sedimentary records from the Chukchi Sea
Masanobu Yamamoto, Seung-Il Nam, Leonid Polyak, Daisuke Kobayashi, Kenta Suzuki, Tomohisa Irino, Koji Shimada
CLIMATE OF THE PAST, 13, 9, 1111, 1127, Sep. 2017, [Peer-reviewed], [Lead author]
English, Scientific journal

The ACER pollen and charcoal database: a global resource to document vegetation and fire response to abrupt climate changes during the last glacial period
Maria Fernanda Sanchez Goni, Stephanie Desprat, Anne-Laure Daniau, Frank C. Bassinot, Josue M. Polanco-Martinez, Sandy P. Harrison, Judy R. M. Allen, R. Scott Anderson, Hermann Behling, Raymonde Bonnefille, Francesc Burjachs, Jose S. Carrion, Rachid Cheddadi, James S. Clark, Nathalie Combourieu-Nebout, Colin. J. Courtney Mustaphi, Georg H. Debusk, Lydie M. Dupont, Jemma M. Finch, William J. Fletcher, Marco Giardini, Catalina Gonzalez, William D. Gosling, Laurie D. Grigg, Eric C. Grimm, Ryoma Hayashi, Karin Helmens, Linda E. Heusser, Trevor Hill, Geoffrey Hope, Brian Huntley, Yaeko Igarashi, Tomohisa Irino, Bonnie Jacobs, Gonzalo Jimenez-Moreno, Sayuri Kawai, A. Peter Kershaw, Fujio Kumon, Ian T. Lawson, Marie-Pierre Ledru, Anne-Marie Lezine, Ping Mei Liew, Donatella Magri, Robert Marchant, Vasiliki Margari, Francis E. Mayle, G. Merna McKenzie, Patrick Moss, Stefanie Mueller, Ulrich C. Mueller, Filipa Naughton, Rewi M. Newnham, Tadamichi Oba, Ramon Perez-Obiol, Roberta Pini, Cesare Ravazzi, Katy H. Roucoux, Stephen M. Rucina, Louis Scott, Hikaru Takahara, Polichronis C. Tzedakis, Dunia H. Urrego, Bas van Geel, B. Guido Valencia, Marcus J. Vandergoes, Annie Vincens, Cathy L. Whitlock, Debra A. Willard, Masanobu Yamamoto
EARTH SYSTEM SCIENCE DATA, 9, 2, 679, 695, Sep. 2017, [Peer-reviewed]
English, Scientific journal

Millennial-scale changes of surface and bottom water conditions in the northwestern Pacific during the last deglaciation
Sunghan Kim, Boo-Keun Khim, Ken Ikehara, Takuya Itaki, Akihiko Shibahara, Masanobu Yamamoto
GLOBAL AND PLANETARY CHANGE, 154, 33, 43, Jul. 2017, [Peer-reviewed]
English, Scientific journal

Estimation of Evolutionary Rates of Mitochondrial DNA in Two Japanese Wood Mouse Species Based on Calibrations with Quaternary Environmental Changes
Kaori Hanazaki, Morihiko Tomozawa, Yutaro Suzuki, Gohta Kinoshita, Masanobu Yamamoto, Tomohisa Irino, Hitoshi Suzuki
ZOOLOGICAL SCIENCE, 34, 3, 201, 210, Jun. 2017, [Peer-reviewed]
English, Scientific journal

北極海の古海洋研究：現状と課題．
M. Yamamoto
Journal of Geological Society of Japan, 124, 3, 16, 01 Jan. 2017, [Peer-reviewed], [Lead author, Corresponding author]
Japanese, Scientific journal

Distribution of detrital minerals and sediment color in western Arctic Ocean and northern Bering Sea sediments: Changes in the provenance of western Arctic Ocean sediments since the last glacial period
Daisuke Kobayashi, Masanobu Yamamoto, Tomohisa Irino, Seung-Il Nam, Yu-Hyeon Park, Naomi Harada, Kana Nagashima, Kazuhisa Chikita, Sei-Ichi Saitoh
POLAR SCIENCE, 10, 4, 519, 531, Dec. 2016, [Peer-reviewed], [Corresponding author]
English, Scientific journal

Holocene sea-ice conditions and circulation at the Chukchi-Alaskan margin, Arctic Ocean, inferred from biomarker proxies
Leonid Polyak, Simon T. Belt, Patricia Cabedo-Sanz, Masanobu Yamamoto, Yu-Hyeon Park
HOLOCENE, 26, 11, 1810, 1821, Nov. 2016, [Peer-reviewed]
English, Scientific journal

Source, settling and degradation of branched glycerol dialkyl glycerol tetraethers in the marine water column
Masanobu Yamamoto, Akifumi Shimamoto, Tatsuo Fukuhara, Yuichiro Tanaka
GEOCHIMICA ET COSMOCHIMICA ACTA, 191, 239, 254, Oct. 2016, [Peer-reviewed]
English, Scientific journal

Palaeobotanical records from Rebun Island and their potential for improving the chronological control and understanding human-environment interactions in the Hokkaido Region, Japan
Stefanie Mueller, Mareike Schmidt, Annette Kossler, Christian Leipe, Tomohisa Irino, Masanobu Yamamoto, Hitoshi Yonenobu, Tomasz Goslar, Hirofumi Kato, Mayke Wagner, Andrzej W. Weber, Pavel E. Tarasov
HOLOCENE, 26, 10, 1646, 1660, Oct. 2016, [Peer-reviewed]
English, Scientific journal

Source, composition and reactivity of sedimentary organic carbon in the river-dominated marginal seas: A study of the eastern Yellow Sea (the northwestern Pacific)
Suk-Hee Yoon, Jung-Hyun Kim, Hi-Il Yi, Masanobu Yamamoto, Jong-Ku Gal, Sujin Kang, Kyung-Hoon Shin
CONTINENTAL SHELF RESEARCH, 125, 114, 126, Aug. 2016, [Peer-reviewed]
English, Scientific journal

Surface ocean cooling in the subarctic North Pacific during the late Pliocene suggests an atmospheric reorganization prior to extensive Northern Hemisphere glaciation
Masanobu Yamamoto, Daisuke Kobayashi
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY, 125, 177, 183, Mar. 2016, [Peer-reviewed]
English, Scientific journal

Climate reconstruction based on GDGT-based proxies in a paleosol sequence in Japan: Postdepositional effect on the estimation of air temperature
Yasuto Yamamoto, Taku Ajioka, Masanobu Yamamoto
QUATERNARY INTERNATIONAL, 397, 380, 391, Mar. 2016, [Peer-reviewed]
English, Scientific journal

Basin filling related to the Philippine Sea Plate motion in Beppu Bay, southwest Japan
Keitaro Yamada, Keiji Takemura, Michinobu Kuwae, Ken Ikehara, Masanobu Yamamoto
JOURNAL OF ASIAN EARTH SCIENCES, 117, 13, 22, Mar. 2016, [Peer-reviewed]
English, Scientific journal

Alkenyl sex pheromone analogs in the hemolymph of an arctiid Eilema japonica and several non-arctiid moths
Takeshi Fujii, Masanobu Yamamoto, Ryo Nakano, Takuya Nirazawa, Yu Rong, Shuang-Lin Dong, Yukio Ishikawa
JOURNAL OF INSECT PHYSIOLOGY, 82, 109, 113, Nov. 2015
English, Scientific journal

Deposition pattern and sources of palynomorphs on the continental margin off Hokkaido Island, northwest Pacific
Yaeko Igarashi, Masanobu Yamamoto, Atsushi Noda, Ken Ikehara, Hajime Katayama
MARINE GEOLOGY, 368, 58, 65, Oct. 2015, [Peer-reviewed]
English, Scientific journal

Distribution, source and transportation of glycerol dialkyl glycerol tetraethers in surface sediments from the western Arctic Ocean and the northern Bering Sea
Yu-Hyeon Park, Masanobu Yamamoto, Seung-Il Nam, Tomohiro Irina, Leonid Polyak, Naomi Harada, Kana Nagashima, Boo-Keun Khim, Kazuhisa Chikita, Sei-Ichi Saitoh
MARINE CHEMISTRY, 165, 10, 24, Oct. 2014, [Peer-reviewed]
English, Scientific journal

Response of vegetation in central Japan to precession during the last 147,000 years: A lignin record from Lake Biwa core BIW08-B
Fukashi Ohira, Masanobu Yamamoto, Keiji Takemura, Akira Hayashida
QUATERNARY INTERNATIONAL, 349, 59, 67, Oct. 2014, [Peer-reviewed]
English, Scientific journal

Branched and isoprenoid glycerol dialkyl glycerol tetraethers in soils and lake/river sediments in Lake Biwa basin and implications for MBT/CBT proxies
Taku Ajioka, Masanobu Yamamoto, Jun Murase
ORGANIC GEOCHEMISTRY, 73, 70, 82, Aug. 2014, [Peer-reviewed]
English, Scientific journal

Millennial-scale alkenone sea surface temperature changes in the northern South China Sea during the past 45,000 years (MD972146)
Da-Cheng Lin, Min-Te Chen, Masanobu Yamamoto, Yusuke Yokoyama
QUATERNARY INTERNATIONAL, 333, 207, 215, May 2014, [Peer-reviewed]
English, Scientific journal

Nutricline shoaling in the eastern Pacific warm pool during the last two glacial maxima
Hasrizal Bin Shaari, Masanobu Yamamoto, Tomohisa Irino, Tadamichi Oba
JOURNAL OF OCEANOGRAPHY, 70, 1, 25, 34, Feb. 2014, [Peer-reviewed]
English, Scientific journal

Water pH and temperature in Lake Biwa from MBT'/CBT indices during the last 280 000 years
T. Ajioka, M. Yamamoto, K. Takemura, A. Hayashida, H. Kitagawa
CLIMATE OF THE PAST, 10, 5, 1843, 1855, 2014, [Peer-reviewed]
English, Scientific journal

Late Pleistocene variation in lignin and fatty acids from core TKN-2004 in a small mountain basin in central Japan
Masanobu Yamamoto, Fukashi Ohira, Fujio Kumon
GEOCHEMICAL JOURNAL, 48, 2, 207, 217, 2014, [Peer-reviewed]
English, Scientific journal

Water pH and temperature in Lake Biwa from MBT'/CBT indices during the last 282 000 years. Climate of the Past,
Ajioka, T, Yamamoto, M, Takemura, K, Hayashida, A, Kitagawa, H
Climate of the Past, 9, 2777, 2788, 2014, [Peer-reviewed]
English, Scientific journal

Confirmation of a Middle Jurassic age for the Eedemt Formation in Dundgobi Province, southeast Mongolia: constraints from the discovery of new spinicaudatans (clam shrimps)
Gang Li, Hisao Ando, Hitoshi Hasegawa, Masanobu Yamamoto, Takashi Hasegawa, Tohru Ohta, Noriko Hasebe, Niiden Ichinnorov
ALCHERINGA, 38, 3, 305, 316, 2014, [Peer-reviewed]
English, Scientific journal

An interlaboratory study of TEX86 and BIT analysis of sediments, extracts, and standard mixtures
Stefan Schouten, Ellen C. Hopmans, Antoni Rosell-Mele, Ann Pearson, Pierre Adam, Thorsten Bauersachs, Edouard Bard, Stefano M. Bernasconi, Thomas S. Bianchi, Jochen J. Brocks, Laura Truxal Carlson, Isla S. Castaneda, Sylvie Derenne, Ayca Dogrul Selver, Koushik Dutta, Timothy Eglinton, Celine Fosse, Valier Galy, Kliti Grice, Kai-Uwe Hinrichs, Yongsong Huang, Arnaud Huguet, Carme Huguet, Sarah Hurley, Anitra Ingalls, Guodong Jia, Brendan Keely, Chris Knappy, Miyuki Kondo, Srinath Krishnan, Sara Lincoln, Julius Lipp, Kai Mangelsdorf, Alfredo Martinez-Garcia, Guillemette Menot, Anchelique Mets, Gesine Mollenhauer, Naohiko Ohkouchi, Jort Ossebaar, Mark Pagani, Richard D. Pancost, Emma J. Pearson, Francien Peterse, Gert-Jan Reichart, Philippe Schaeffer, Gaby Schmitt, Lorenz Schwark, Sunita R. Shah, Richard W. Smith, Rienk H. Smittenberg, Roger E. Summons, Yoshinori Takano, Helen M. Talbot, Kyle W. R. Taylor, Rafael Tarozo, Masao Uchida, Bart E. van Dongen, Benjamin A. S. Van Mooy, Jinxiang Wang, Courtney Warren, Johan W. H. Weijers, Josef P. Werne, Martijn Woltering, Shucheng Xie, Masanobu Yamamoto, Huan Yang, Chuanlun L. Zhang, Yige Zhang, Meixun Zhao, Jaap S. Sinninghe Damste
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, 14, 12, 5263, 5285, Dec. 2013, [Peer-reviewed]
English, Scientific journal

Enhanced upwelling in the eastern equatorial Pacific at the last five glacial terminations
Hasrizal bin Shaari, Masanobu Yamamoto, Tomohisa Irino
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY, 386, 8, 15, Sep. 2013, [Peer-reviewed]
English, Scientific journal

Intense winter cooling of the surface water in the northern Okinawa Trough during the last glacial period
Masanobu Yamamoto, Midori Kishizaki, Tadamichi Oba, Hodaka Kawahata
Journal of Asian Earth Sciences, 69, 86, 92, 05 Jun. 2013, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

Stratigraphy and wiggle-matching-based age-depth model of late Holocene marine sediments in Beppu Bay, southwest Japan
Michinobu Kuwae, Masanobu Yamamoto, Ken Ikehara, Tomohisa Irino, Keiji Takemura, Takuya Sagawa, Tatsuhiko Sakamoto, Minoru Ikehara, Hidetaka Takeoka
Journal of Asian Earth Sciences, 69, 133, 148, 05 Jun. 2013, [Peer-reviewed]
English, Scientific journal

Precisely dated AMS C-14 marine cores reveal the complexity of millennial-scale Asian monsoon variability in the northern South China Sea (MD972146, MD972148)
Da-Cheng Lin, Min-Te Chen, Masanobu Yamamoto, Yusuke Yokoyama
JOURNAL OF ASIAN EARTH SCIENCES, 69, 93, 101, Jun. 2013, [Peer-reviewed]
English, Scientific journal

The East Asian winter monsoon variability in response to precession during the past 150 000 yr
M. Yamamoto, H. Sai, M. -T. Chen, M. Zhao
CLIMATE OF THE PAST, 9, 6, 2777, 2788, 2013, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

Glycerol dialkyl glycerol tetraethers and TEX86 index in sinking particles in the western North Pacific
Masanobu Yamamoto, Akifumi Shimamoto, Tatsuo Fukuhara, Yuichiro Tanaka, Joji Ishizaka
ORGANIC GEOCHEMISTRY, 53, 52, 62, Dec. 2012, [Peer-reviewed]
English, Scientific journal

Distribution of glycerol dialkyl glycerol tetraethers, alkenones and polyunsaturated fatty acids in suspended particulate organic matter in the East China Sea
Takahiro Nakanishi, Masanobu Yamamoto, Tomohisa Irino, Ryuji Tada
JOURNAL OF OCEANOGRAPHY, 68, 6, 959, 970, Dec. 2012, [Peer-reviewed]
English, Scientific journal

Centennial-scale winter monsoon variability in the northern East China Sea during the Holocene
Takahiro Nakanishi, Masanobu Yamamoto, Ryuji Tada, Hirokuni Oda
JOURNAL OF QUATERNARY SCIENCE, 27, 9, 956, 963, Dec. 2012, [Peer-reviewed]
English, Scientific journal

Insolation and cross-hemispheric controls on Australian monsoon variability over the past 180 ka: new evidence from offshore southeastern Papua New Guinea
Liang-Jian Shiau, Min-Te Chen, Chih-An Huh, Masanobu Yamamoto, Yusuke Yokoyama
JOURNAL OF QUATERNARY SCIENCE, 27, 9, 911, 920, Dec. 2012, [Peer-reviewed]
English, Scientific journal

Out of the Tropics: The Pacific, Great Basin Lakes, and Late Pleistocene Water Cycle in the Western United States
Mitchell Lyle, Linda Heusser, Christina Ravelo, Masanobu Yamamoto, John Barron, Noah S. Diffenbaugh, Timothy Herbert, Dyke Andreasen
SCIENCE, 337, 6102, 1629, 1633, Sep. 2012, [Peer-reviewed]
English, Scientific journal

Variabilities in detrital supply and the marine environment at ODP Site 1237 in the southeast Pacific Ocean since the late Oligocene.
Noma Eriko, Irino Tomohisa, Shaari Hasrizal, Yamamoto Masanobu
Annual Meeting of the Geological Society of Japan, 2012, 214, 214, The Geological Society of Japan, 2012

Climate and vegetation in Hokkaido, northern Japan, since the LGM: Pollen records from core GH02-1030 off Tokachi in the northwestern Pacific
Yaeko Igarashi, Masanobu Yamamoto, Ken Ikehara
JOURNAL OF ASIAN EARTH SCIENCES, 40, 6, 1102, 1110, Apr. 2011, [Peer-reviewed]
English, Scientific journal

Paleoenvironmental changes in the northern South China Sea over the past 28,000 years: A study of TEX86-derived sea surface temperatures and terrestrial biomarkers
Tomoya Shintani, Masanobu Yamamoto, Min-Te Chen
JOURNAL OF ASIAN EARTH SCIENCES, 40, 6, 1221, 1229, Apr. 2011, [Peer-reviewed]
English, Scientific journal

Paleotemperature changes in the subarctic North Pacific over the last 5.8 million years
Kobayashi Daisuke, Yamamoto Masanobu
Abstracts of Annual Meeting of the Geochemical Society of Japan, 58, 23, 23, GEOCHEMICAL SOCIETY OF JAPAN, 2011
本研究では、北太平洋亜寒帯域に位置するOcean Drilling Program Site 882の海底堆積物コアから採取された試料から、北太平洋亜寒帯域の過去580万年間の水温を復元した．水温の復元はTEX86古水温推定法(Shouten et al., 2002)を用いて行った．TEX86古水温は過去580万年間で-1℃から12℃の水温の変動を示した．TEX86古水温は100万年スケールの長周期変動に10万年スケールの短周期変動が重複したような変動を示した．

Origin of rhythmical bedding in mid-Cretaceous lacustrine deposits, southeast Mongolia: Implication for terrestrial environmental changes during the OAE interval
Hasegawa Hitoshi, Ando Hisao, Hasegawa Takashi, Ohta Toru, Yamamoto Masanobu, Hasebe Noriko, Li Gang, Ichinnorov Niiden
Abstracts of Annual Meeting of the Geochemical Society of Japan, 58, 22, 22, GEOCHEMICAL SOCIETY OF JAPAN, 2011
本研究はモンゴルのアプチアン期湖成層（シネフダグ層）を対象に，OAE1a時の陸域環境変動の解明を試みている．シネフダグ湖成層は，頁岩とドロマイトのリズミカルな互層（数10cm，数m，10~20 mサイクル）からなる．本研究では，その堆積メカニズムを解明するため，堆積相解析，鉱物組成分析，有機地球化学分析を行った．C/N比およびロックエバル分析の結果，シネフダグ湖成層の有機物は主に湖内の藻類に由来することが示唆された．またドロマイト層準では藻類やバクテリアが卓越するのに対し，頁岩層準では藻類に加えて湖岸からの高等植物起源有機物の流入も寄与していたことが示唆された．これらの結果と堆積相解析から，シネフダグ湖成層に見られる頁岩とドロマイトのリズミカルな互層（数千年，数万年，数10万年サイクルに相当）は，地球軌道要素の変動に起因した湖水位の変動，すなわち湿潤－乾燥といった気候変動に対応している可能性が示唆された．

Application of temperature reconstruction technique based on branched GDGT distributions to Lake Biwa sediments
Ajioka Taku, Yamamoto Masamobu, Takemura Keiji, Hayasida Akira
Abstracts of Annual Meeting of the Geochemical Society of Japan, 58, 11, 11, GEOCHEMICAL SOCIETY OF JAPAN, 2011
Branched GDGTs in soils taken from the watershed of Lake Biwa and in sediment core (BIW07-6) retrieved from the lake were analyzed. The dependency of CBT and MBT on pH and mean annual air temperature (MAAT) in our sample set is different from that in global set of soil samples. This difference suggests that some local factor(s) is(are) crucial in the relationship between MBT/CBT and pH/MAAT. The branched GDGT distributions of the surface sediment of BIW07-6 were remarkably different from those of soils, which suggests that branched GDGTs of the sediment were not derived from the watershed soils, but were most likely produced in the lake. CBT-pH supports that branched GDGTs in the sediment were produced in the bottom water and/or the sediment. The variation of estimated paleotemperatures in core BIW07-06 is in harmony with pollen records in nearby cores, suggesting that MBT/CBT index is useful for paleotemperature estimate.

Relationship between the Andean volcanism and paleoclimatic /paleoceanographic changes based on ODP Site 1237 core
Irino Tomohisa, Yamamoto Masanobu
Abstracts of Annual Meeting of the Geochemical Society of Japan, 58, 110, 110, GEOCHEMICAL SOCIETY OF JAPAN, 2011
新生代における山地の隆起と気候変動の関係を検討するために、ペルー沖ODP Site 1237コアの鉱物・化学組成を検討する。特に堆積物コアに含まれる中央アンデス起源と思われる火山灰の寄与と砕屑物および海洋炭酸塩組成の分析を通して、この地域の長い時間スケールの火山活動と気候・海洋変動との間の関係を解析することを目的とした。コアは前期漸新世までおよんでおり、4 Maまでは95%以上が炭酸塩の軟泥である。砕屑鉱物組成が検討できた2.5 Ma以降では、火山活動の活発化に遅れて乾燥化が起こることが示唆された。

Meridional Sea Surface Temperature Evolution in the Eastern Tropical Pacific during the Last Glacial Cycles
bin Shaari Hasrizal, Yamamoto Masanobu, Irino Tomohisa
Abstracts of Annual Meeting of the Geochemical Society of Japan, 58, 144, 144, GEOCHEMICAL SOCIETY OF JAPAN, 2011
ODPサイト1237, 1239, 1241の堆積物に含まれるグリセロール・ジアルキル・グリセロール・テトラエーテルを分析することにより過去１５万年間のTEX86古水温変動を求め，水温の緯度勾配の変化を検討した．

Paleotemperature estimation over the past 10,000 years by the application of GDGT-based proxy in soil sequences from the Ono River Basin, Oita, Japan
Yamamoto Yasuto, Ajioka Taku, Yamamoto Masanobu, Takemura Keiji
Abstracts of Annual Meeting of the Geochemical Society of Japan, 58, 10, 10, GEOCHEMICAL SOCIETY OF JAPAN, 2011
MBT/CBT index based on the composition of branched Glycerol Dialkyl Glycerol Tetraethers(GDGTs) was recently proposed as a proxy of terrestrial paleo-air temperature. In this study, we reconstructed paleotemperature changes during the Holocene at the upstream of the Ono River Basin by analyzing a soil sequence exposed at the flank of Mr. Kuju and a marine sequence drilled at the mouth of the Ono River, Kyushu, Japan.

Winter monsoon variability during the last 40,000 years; evidence from TEX86-derived temperatures in the northern East China Sea
Yamamoto Masanobu, Nakanishi Takahiro, Kishizaki Midori, Irino Tomohisa, Tada Ryuji, Oda Hirokuni
Abstracts of Annual Meeting of the Geochemical Society of Japan, 58, 142, 142, GEOCHEMICAL SOCIETY OF JAPAN, 2011
We discuss winter monsoon variability during the last 40,000 years, based on TEX86-derived temperature records from cores MD98-2195, KY0704 PC-1, and KY0704 PL-1 retrieved from the northern East China Sea.

GDGT-based proxy approach to paleo-environmental reconstruction in Holocene sediments from the Chukchi-Alaska Shelf in the Arctic Ocean
Park Yu-Hyeon, Yamamoto Masanobu, Polyak Leonid
Abstracts of Annual Meeting of the Geochemical Society of Japan, 58, 111, 111, GEOCHEMICAL SOCIETY OF JAPAN, 2011
The Arctic Ocean plays an important role in global climate changes by positive feedbacks involving changes in sea-ice coverage, thermohaline circulation, and boreal vegetation (Miller et al., 2010). The Pacific sector of in the Arctic Ocean is sensitive to global climate changes and the sea ice coverage responds to changes in temperature and the inflow of extent of input of the Pacific water. The Alaska margin in the western Arctic receives considerable amount of sediments from the Yukon River and smaller rivers in northern Alaska (Ortiz et al., 2009).We investigated molecular distributions of branched and isoprenoid glycerol dialkyl glycerol tetraethers (GDGTs) as terrestrial and marine biomarkers, respectively, to explore possibilities of paleo-temperature estimation and to estimate GDGT-based temperature, the contribution of soil organic matter and the soil pH. We discuss whether GDGT composition in marine sediment reflect sea surface temperature (SST) and mean annual air temperatures (MAAT) and, the changes in the provenance of terrestrial OM in Chukchi- Alaska margin sediments since the early Holocene. The SST and MAAT estimated using a global calibration equation proposed by Kim et al. (2010) and Weijers et al. (2008), respectively, in the core-top sediments show much higher values than modern annual temperature measured by instruments in northern Alaska. The reconstructed temperature must be biased toward a warmer direction. The each global calibration by Kim et al. (2010) and Weijers et al. (2008) does not fully cover polar region and the temperature estimate was done by extrapolation. We thus need future effort to create a calibration equation based on the data set in polar region to improve temperature estimates. The changing patterns of paleo-temperatures in both cores show a similar variation. The TEX86L-derived SST indicates that it was cooler in the middle Holocene than in the early and late Holocene. Both cores show a warming in air temperature and an increase in soil pH over the past 10 ka. BIT value shows a decreasing pattern on both cores over the past 10 ka. In particular, parameters from 9.5 to 7 ka show significant variation. The climatic oscillation from 9.5 to 7 ka is consistent with rapid climate changes observed globally and an area near northern Alaska margin (Brachfeld et al., 2009). These trends suggest that 1) the warming in northern Alaska began since 10 ka, 2) the contribution of marine OM became larger 3) changes in soil pH may have reflected changes in the provenance of soil.

urassic-Cretaceous lacustrine deposits in the East Gobi Basin, southeast Mongolia
Hisao Ando, Hitoshi Hasegawa, Takashi Hasegawa, Toru Ohta, Masanobu Yamamoto, Noriko Hasebe, Gang Li, Niiden Ichinnorovu
Jour. Geol. Soc. Japan, 117, 11, XI, XII, The Geological Society of Japan, 2011, [Peer-reviewed]
English

Core top TEX86 values in the south and equatorial Pacific
Sze Ling Ho, Masanobu Yamamoto, Gesine Mollenhauer, Masao Minagawa
ORGANIC GEOCHEMISTRY, 42, 1, 94, 99, Jan. 2011, [Peer-reviewed]
English, Scientific journal

Warm pool hydrological and terrestrial variability near southern Papua New Guinea over the past 50k
Liang-Jian Shiau, Min-Te Chen, Steven C. Clemens, Chih-An Huh, Masanobu Yamamoto, Yusuke Yokoyama
GEOPHYSICAL RESEARCH LETTERS, 38, 8, 1, 6, Jan. 2011, [Peer-reviewed]
English, Scientific journal

Millennial-scale variability in vegetation records from the East Asian Islands: Taiwan, Japan and Sakhalin
Hikaru Takahara, Yaeko Igarashi, Ryoma Hayashi, Fujio Kumon, Ping-Mei Liew, Masanobu Yamamoto, Sayuri Kawai, Tadamichi Oba, Tomohisa Irino
QUATERNARY SCIENCE REVIEWS, 29, 21-22, 2900, 2917, Oct. 2010, [Peer-reviewed]
English, Scientific journal

Climato-hydrological fluctuations printed in long lacustrine records in Lake Hovsgol, Mongolia
K. Kashiwaya, S. Ochiai, G. Sumino, T. Tsukamoto, A. Szyniszewska, M. Yamamoto, A. Sakaguchi, N. Hasebe, H. Sakai, T. Watanabe, T. Kawai
QUATERNARY INTERNATIONAL, 219, 1-2, 178, 187, Jun. 2010, [Peer-reviewed]
English, Scientific journal

The relative contribution of dinoflagellate photosynthesis and stored lipids to the survivorship of symbiotic larvae of the reef-building corals
Saki Harii, Masanobu Yamamoto, Ove Hoegh-Guldberg
MARINE BIOLOGY, 157, 6, 1215, 1224, Jun. 2010, [Peer-reviewed]
English, Scientific journal

Characteristics of organic matter in uranium-rich coaly shales from Miocene sequence at Kanamaru, Japan
山本 正伸, 関 陽児, 内藤 一樹
Bulletin of the Geological Survey of Japan, 61, 9, 325, 336, National Institute of Advanced Industrial Science and Technology, Geological Survey of Japan, 2010, [Peer-reviewed]
Japanese, Scientific journal, &nbsp;&nbsp;&nbsp;&nbsp;We obtained a continuous 45 m-long core from the Miocene sedimentary sequence and basement Cretaceous granite at Kanamaru, northeast Japan. The Miocene sequence intercalates with a uranium-rich seam (U = 25-100 ppm; Th = 23-42 ppm). We analyzed the kerogen and biomarkers in the core to characterize the organic matter.<br>&nbsp;&nbsp;&nbsp;&nbsp;Visual kerogen analysis indicated that coaly and woody kerogen is abundant in relatively organic-rich samples, while amorphous kerogen is abundant in organic-lean samples. Pyrolysis gas chromatography-mass spectrometry demonstrated that the organic matter in pyrolysates comprises mainly alkyl-aromatic hydrocarbons (alkyl-benzenes, alkyl-indenes, alkyl-naphthalenes, etc.) and n-alkanes. Acyclic isoprenoid alkanes (mainly pristane), n-alkenes, and n-fatty acids were detected as minor components. Most of these compounds are characteristic of the typeIII kerogen that derived from terrestrial higher plants. These results suggest that amorphous kerogen originated from terrestrial higher plants, and we speculate that they were heavily degraded by oxidation and lost their woody texture.<br>&nbsp;&nbsp;&nbsp;&nbsp;Thermal alteration index (TAI) of <i>Pinus</i> pollen was about 2.6, and Tmax values of Rock-Eval pyrolysis range from 441 &deg;C to 444 &deg;C, which indicate that the thermal maturation of the coaly shale reached the stage of early catagenesis. This maturity was also suggested by high abundance of diagenetically generated isomers of hopanes in pyrolysates.<br>&nbsp;&nbsp;&nbsp;&nbsp;In the sediment sequence, a peak of uranium and uranium/thorium ratio is ca. 2 m shallower than the peak of organic carbon content, but it corresponds to a lithological boundary. This inconsistency suggests that organic matter was not involved in concentrating uranium. Uranium was possibly concentrated from groundwater at the lithological boundaries between different redox levels during the period of high groundwater level.

Response of mid-latitude North Pacific surface temperatures to orbital forcing and linkage to the East Asian summer monsoon and tropical ocean-atmosphere interactions
Masanobu Yamamoto
JOURNAL OF QUATERNARY SCIENCE, 24, 8, 836, 847, Dec. 2009, [Peer-reviewed]
English, Scientific journal

Biomarker Records from Core GH02-1030 off Tokachi in the Northwestern Pacific over the Last 23,000 Years: Environmental Changes during the Last Deglaciation
Masaki Inagaki, Masanobu Yamamoto, Yaeko Igarashi, Ken Ikehara
JOURNAL OF OCEANOGRAPHY, 65, 6, 847, 858, Dec. 2009, [Peer-reviewed]
English, Scientific journal

GC/MS analysis of unsaturated long-chain alkenes in culture samples of recent Haptophyte Emiliania huxleyi
Amo Miki, Hagino Kyoko, Suzuki Noriyuki, Horiguchi Takeo, Yamamoto Masanobu
Researches in organic geochemistry, 25, 0, 91, 94, The Japanese Association of Organic Geochemists, 30 Nov. 2009, [Peer-reviewed]
Japanese, Scientific journal

Response of the North Pacific to orbital forcing during late Quaternary from the view of paleotemperature records(Progress in micropaleontology and paleoceanography as the late Cenozoic environmental tracers)
Yamamoto Masanobu
Fossils., 0, 86, 45, 58, Palaeontological Society of Japan, 16 Oct. 2009, [Peer-reviewed]
Japanese, Scientific journal, We present a palaeoceanographic perspective of the North Pacific during the last two glacial cycles based on U^<K'>_<37>-derived palaeotemperature records from Japan and California margins. At the Japan margin, the sea surface temperature (SST) in the Kuroshio-Oyashio transition has varied in response to precessional cycle. At the California margin, SST has varied in response to ice volume changes, but the SST difference between inshore and offshore sites (ΔSST_<northeastern Pacific (NEP)>=SST_<ODP1014>-SST_<ODP1016>) has responded to precessional cycle. Comparison of ΔSST_<NEP> and the SST...

Paleotemperature response to monsoon activity in the Japan Sea during the last 160 kyr
Kazuho Fujine, Ryuji Tada, Masanobu Yamamoto
Palaeogeography, Palaeoclimatology, Palaeoecology, 280, 3-4, 350, 360, 15 Sep. 2009, [Peer-reviewed]
English, Scientific journal

Changes in terrestrial organic matter input to the Mendeleev Ridge, western Arctic Ocean, during the Late Quaternary
Masanobu Yamamoto, Leonid Polyak
GLOBAL AND PLANETARY CHANGE, 68, 1-2, 30, 37, Jul. 2009, [Peer-reviewed]
English, Scientific journal

The 1500-year climate oscillation in the midlatitude North Pacific during the Holocene
Dai Isono, Masanobu Yamamoto, Tomohisa Irino, Tadamichi Oba, Masafumi Murayama, Toshio Nakamura, Hodaka Kawahata
GEOLOGY, 37, 7, 591, 594, Jul. 2009, [Peer-reviewed]
English, Scientific journal

Glacial-interglacial variation in the North Pacific subtropical gyre circulation : Linkage to tropical ocean-atmosphere interactions and the East Asian summer monsoon
YAMAMOTO Masanobu, IGARASHI Yaeko, OBA Tadamichi
The Quaternary research, 48, 3, 195, 206, 01 Jun. 2009, [Peer-reviewed]
Japanese, Scientific journal

An interlaboratory study of TEX86 and BIT analysis using high-performance liquid chromatography-mass spectrometry
Stefan Schouten, Ellen C. Hopmans, Jaap van der Meer, Anchelique Mets, Edouard Bard, Thomas S. Bianchi, Aaron Diefendorf, Marina Escala, Katharine H. Freeman, Yoshihiro Furukawa, Carme Huguet, Anitra Ingalls, Guillemette Menot-Combes, Alexandra J. Nederbragt, Masahiro Oba, Ann Pearson, Emma J. Pearson, Antoni Rosell-Mele, Philippe Schaeffer, Sunita R. Shah, Timothy M. Shanahan, Richard W. Smith, Rienk Smittenberg, Helen M. Talbot, Masao Uchida, Benjamin A. S. Van Mooy, Masanobu Yamamoto, Zhaohui Zhang, Jaap S. Sinninghe Damste
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS, 10, Mar. 2009, [Peer-reviewed]
English, Scientific journal

Environmental changes during the Last Interglacial period around the Japanese Islands; comparison and integration of land and marine environments
Kumon Fujio, Yamamoto Masanobu, Nagahashi Yoshitaka, Aoike Kan
The Journal of the Geological Society of Japan, 115, 7, 301, 310, The Geological Society of Japan, 2009, [Peer-reviewed], [Invited]
Japanese, We reviewed the results of previous studies on paleoclimate and paleoenvironment in and around the Japanese Islands during the Last Interglacial period. Sediment cores recovered from deep-sea settings around the Japanese Islands provide valuable information in understanding the ocean paleoenvironment and age framework since marine isotope stage 6. Analyses of pollen, diatoms, and total organic carbon in lake sediments have contributed to clarifying the land climate in detail, in combination with age constraints provided by tephra marker beds. Great progress has been made in tephra stratigra...

Glacial-interglacial variation in the North Pacific subtropical gyre
Yamamoto Masanobu
The Journal of the Geological Society of Japan, 115, 7, 325, 332, The Geological Society of Japan, 2009, [Peer-reviewed]
Japanese, Scientific journal, This study presents a new perspective of North Pacific paleoceanography over the last two glacial cycles, based on assessments of U37K’-derived paleotemperature records from IMAGES Core MD01-2421 off central Japan and Ocean Drilling Program (ODP) Sites 1014 and 1016 off California. The temperature differences between ODP Sites 1014 and 1016 (ΔSSTNEP=SSTODP1014-SSTODP1016) reflect the intensity of the California Current. Comparison of ΔSSTNEP and SST derived from Core MD01-2421 reveals anti-phase variations: high ΔSSTNEP (weakening of the California Current) corresponds to low SST at the Jap...

古水温変動からみた北太平洋の軌道強制力に対する応答　　　　　　　　　　　　　　　
Yamamoto Masanobu
化石, 86, 44, 57, 2009, [Peer-reviewed]
Japanese, Scientific journal

現生ハプト藻Emiliania huxleyi培養試料中の長鎖アルケンのGC/MS解析　　　　　　　　　　　　　　　
天羽美紀, 萩野恭子, 鈴木徳行, 堀口健雄, 山本正伸
Researches in Organic Geochemistry, 25, 91, 94, 2009, [Peer-reviewed]
Japanese, Scientific journal

Slow warming of the northern South China Sea during the last deglaciation
Tomoya Shintani, Masanobu Yamamoto, Min-Te Chen
TERRESTRIAL ATMOSPHERIC AND OCEANIC SCIENCES, 19, 4, 341, 346, Aug. 2008, [Peer-reviewed]
English, Scientific journal

Sea surface temperature, productivity, and terrestrial flux variations of the southeastern South China Sea over the past 800000 years (IMAGES MD972142)
Liang-Jian Shiau, Pai-Sen Yu, Kuo-Yen Wei, Masanobu Yamamoto, Teh-Quei Lee, Ein-Fen Yu, Tien-Hsi Fang, Min-Te Chen
TERRESTRIAL ATMOSPHERIC AND OCEANIC SCIENCES, 19, 4, 363, 376, Aug. 2008, [Peer-reviewed]
English, Scientific journal

Ether lipids of archaea as tools for environmental studies.
Oba Masahiro, Kaiho Kunio, Kakegawa Takeshi, Yamamoto Masanobu, Sakata Susumu, Furukawa Yoshihiro, Sato Seigo
Abstracts of Annual Meeting of the Geochemical Society of Japan, 55, 21, 21, GEOCHEMICAL SOCIETY OF JAPAN, 2008
古細菌由来のエーテル脂質を存在状態別に分析する手法を用いて、現世や地質時代の様々な試料について有機地球化学的研究を行った。1.暁新世/始新世の地球温暖化事変期（PETM）の堆積物中に含まれるテトラエーテル脂質を分析し、その濃度からTEX86を算出し、当時の海洋表層温度を推定した。その結果、PETM最初期に寒冷化を挟む２回の温暖化事変が起きたことが判明した。2.水曜海山の人口熱水孔から採取された沈殿物中のエーテル脂質を分析した結果、メタン菌に特徴的なエーテル脂質を検出した。他のバイオマーカー分析や鉱物分析などの結果も合わせて考察した結果、人工熱水孔内における微生物活動は多様性に富み、非常に活発であったことが判明した。

Reconstruction of TEX86 paleotemperatures reconstruction in the Beppu Bay over the last 1500 years.
ichikawa norio, yamamoto masanobu, okino tatsufumi, kuwae mishinobu, sugimoto takashige, takeoka hidetaka
Abstracts of Annual Meeting of the Geochemical Society of Japan, 55, 413, 413, GEOCHEMICAL SOCIETY OF JAPAN, 2008
地球環境の将来予測において，歴史時代の気温，降水量の変化を復元することが急務である。本研究では，別府湾から採取した海底コアに含まれるテトラエーテル脂質（GDGT）を分析することにより，過去1500年間の別府湾の水温の変動を復元した。復元した結果、西暦500年頃から1040年頃にかけては14～16℃前後の低い値を推移し、1050年頃から1400年頃の間では17℃前後の高温になり、1300年頃から2005年までは13℃～17℃まで範囲で激しく変動した。

Holocene temperature change in the northern East China Sea
Nakanishi Takahiro, Yamamoto Masanobu, Okino Tatsufumi, Irino Tomohisa, Oda Hirokuni, Yokoyama Yusuke, Matsuzaki Hiroyuki, Tada Ryuji
Abstracts of Annual Meeting of the Geochemical Society of Japan, 55, 414, 414, GEOCHEMICAL SOCIETY OF JAPAN, 2008
KY07-04航海により採取されたピストンコアPC-1とマルチプルコアPL-1を使用して、東シナ海北部の過去5000年間の表層水温を、バイオマーカー指標であるアルケノンに基づくU^K₃₇'とGDGT指標であるTEX₈₆を用いて、40年から80年間隔と時間的解像度を高めて水温変動を復元した。アルケノン水温は過去5000年間に渡って23.5℃から24℃とほぼ一定の値を示した。一方、TEX₈₆水温はアルケノン水温とは異なり、20.4℃から24.8℃の間で激しく変動した。両者の水温変動に違いが見られる理由として、それぞれの物質をつくる生物の生息時期や深度の違いが挙げられるが、GDGTをつくるクレンアーキオータの生息深度は不明である。これを解決する手段として、本年５月に行われたKT08-10航海にてコアサイト付近の表層から中層の海水を採取し、ろ過後脂質を抽出し、GDGTを分析した。発表では、海水より求めたTEX₈₆水温の結果も合わせて報告する。

Late Pleistocene changes in terrestrial organic matter input to the Mendeleev Ridge, western Arctic Ocean
Yamamoto Masanobu, Polyak Leonid
Abstracts of Annual Meeting of the Geochemical Society of Japan, 55, 420, 420, GEOCHEMICAL SOCIETY OF JAPAN, 2008
将来の気候変化を予測する上で，気候変動における北極域の役割を解明することが急務である．過去の北極海の環境を復元することは北極域の役割を解明するためのひとつの手段であるが，北極海堆積物は一般に貧化石であり，微古生物学的手法による古環境研究に制約が多い．そこで，近年バイオマーカーを用いた古環境復元が期待されている．本研究では，HOTRAX'05（Healy-Oden Trans Arctic Expedition 2005）においてメンデレーフ海嶺から採取されたHLY0503-08JPCコアの後期第四紀堆積物のn-アルカンとテトラエーテル脂質（GDGT）を分析し，過去13万年間の北極海への陸起源有機物の流れ込みを復元した．長鎖n-アルカンとGDGTの濃度は堆積物の色調の変化（灰色層と褐色層の互層）に対応して周期的に変動する．氷期および亜氷期に堆積した灰色層は高等植物起源n-アルカン（高CPI）と分枝GDGTに富み，陸上植物と土壌有機物の寄与が大きい．これらの化合物は大陸氷床による陸上土壌の浸食によりもたらされたと考えられる．BIT指標は灰色層よりも褐色層で低く，間氷期および亜間氷期では北極海でのクレンアーキオータの生産が高まったことが示唆された．熟成有機物起源ｎ-アルカン（低CPI）はスパイクピーク状に高濃度を示し，過去13万年間の層準内で16本のピークが認められた．いくつかの高濃度ピークはユーラシア氷床崩壊と淡水流出のタイミングと一致しており，アイスダム湖の崩壊にともなう基盤岩の浸食により，熟成有機物がもたらされたと考えられる．この熟成有機物ピークは，北極域における氷床の崩壊史を復元する手がかりになりうる．

Late Pleistocene changes in terrestrial biomarkers in sediments from the central Arctic Ocean
Masanobu Yamamoto, Tatsufumi Okino, Saiko Sugisaki, Tatsuhiko Sakamoto
ORGANIC GEOCHEMISTRY, 39, 6, 754, 763, 2008, [Peer-reviewed]
English, Scientific journal

Seasonal and depth variations in molecular and isotopic alkenone composition of sinking particles from the western North Pacific
Masanobu Yamamoto, Akifumi Shimamoto, Tatsuo Fukuhara, Hiroshi Naraoka, Yuichiro Tanaka, Akira Nishimura
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS, 54, 9, 1571, 1592, Sep. 2007, [Peer-reviewed]
English, Scientific journal

Comment on "Monsoon related changes in sea surface productivity and water column denitrification in the Eastern Arabian Sea during the last glacial cycle" by V.K. Banakar, T. Oba, A.R. Chodankar, T. Kuramoto, M. Yamamoto, M. Minagawa
V. K. Banakar, T. Oba, A. R. Chodankar, T. Kuramoto, M. Yamamoto, M. Minagawa
MARINE GEOLOGY, 238, 1-4, 115, 117, Mar. 2007, [Peer-reviewed]
English

The California current system during the last 136,000 years: response of the North Pacific High to precessional forcing
Masanobu Yamamoto, Masumi Yamamuro, Yuichiro Tanaka
QUATERNARY SCIENCE REVIEWS, 26, 3-4, 405, 414, Feb. 2007, [Peer-reviewed]
English, Scientific journal

Temporal changes in settlement, lipid content and lipid composition of larvae of the spawning hermatypic coral Acropora tenuis
Saki Harii, Kazuo Nadaoka, Masanobu Yamamoto, Kenji Iwao
MARINE ECOLOGY PROGRESS SERIES, 346, 89, 96, 2007, [Peer-reviewed]
English, Scientific journal

Erratum: Arctic hydrology during global warming at the Palaeocene/Eocene thermal maximum (Nature (2006) 442 (671-675))
Mark Pagani, Nikolai Pedentchouk, Matthew Huber, Appy Sluijs, Stefan Schouten, Henk Brinkhuis, Jaap S Sinninghe, Damsté, Gerald, R. Dickens, Jan Backman, Steve Clemens, Thomas Cronin, Frédérique Eynaud, Jérôme Gattacceca, Martin Jakobsson, Ric Jordan, Michael Kaminski, John King, Nalân Koc, Nahysa C. Martinez, Jens Matthiessen, David McInroy, Theodore C. Moore, Kathryn Moran, Matthew O'Regan, Jonaotaro Onodera, Heiko Pälike, Brice Rea, Domenico Rio, Tatsuhiko Sakamoto, David C. Smith, Ruediger Stein, Kristen E, K, St. John, Itsuki Suto, Noritoshi Suzuki, Kozo Takahashi, Mahito Watanabe, Masanobu Yamamoto
Nature, 443, 598, Oct. 2006, [Peer-reviewed]

Arctic hydrology during global warming at the Palaeocene/Eocene thermal maximum
Mark Pagani, Nikolai Pedentchouk, Matthew Huber, Appy Sluijs, Stefan Schouten, Henk Brinkhuis, Jaap S. Sinninghe Damste, Gerald R. Dickens
NATURE, 442, 7103, 671, 675, Aug. 2006, [Peer-reviewed]
English, Scientific journal

Long term Aleutian Low dynamics and obliquity-controlled oceanic primary production in the mid-latitude western North Pacific (Core MD01-2421) during the last 145,000 years
Toshinori Ueshima, Masanobu Yamamoto, Tomohisa Irino, Tadamichi Oba, Masao Minagawa, Hisashi Narita, Masafumi Murayama
GLOBAL AND PLANETARY CHANGE, 53, 1-2, 21, 28, Aug. 2006, [Peer-reviewed]
English, Scientific journal

Paleoceanographic change off central Japan since the last 144,000 years based on high-resolution oxygen and carbon isotope records
Tadamichi Oba, Tomohisa Irino, Masanobu Yamamoto, Masafumi Murayama, Akira Takamura, Kaori Aoki
GLOBAL AND PLANETARY CHANGE, 53, 1-2, 5, 20, Aug. 2006, [Peer-reviewed]
English, Scientific journal

Episodic fresh surface waters in the Eocene Arctic Ocean
H Brinkhuis, S Schouten, ME Collinson, A Sluijs, JSS Damste, GR Dickens, M Huber, TM Cronin, J Onodera, K Takahashi, JP Bujak, R Stein, J van der Burgh, JS Eldrett, IC Harding, AF Lotter, F Sangiorgi, HVV Cittert, JW de Leeuw, J Matthiessen, J Backman, K Moran
NATURE, 441, 7093, 606, 609, Jun. 2006, [Peer-reviewed]
English, Scientific journal

Subtropical arctic ocean temperatures during the Palaeocene/Eocene thermal maximum
A Sluijs, S Schouten, M Pagani, M Woltering, H Brinkhuis, JSS Damste, GR Dickens, M Huber, GJ Reichart, R Stein, J Matthiessen, LJ Lourens, N Pedentchouk, J Backman, K Moran
NATURE, 441, 7093, 610, 613, Jun. 2006, [Peer-reviewed]
English, Scientific journal

The Cenozoic palaeoenvironment of the Arctic Ocean
Kathryn Moran, Jan Backman, Henk Brinkhuis, Steven C. Clemens, Thomas Cronin, Gerald R. Dickens, Frederique Eynaud, Jerome Gattacceca, Martin Jakobsson, Richard W. Jordan, Michael Kaminski, John King, Nalan Koc, Alexey Krylov, Nahysa Martinez, Jens Matthiessen, David McInroy, Theodore C. Moore, Jonaotaro Onodera, Matthew O'Regan, Heiko Palike, Brice Rea, Domenico Rio, Tatsuhiko Sakamoto, David C. Smith, Ruediger Stein, Kristen St John, Itsuki Suto, Noritoshi Suzuki, Kozo Takahashi, Mahito Watanabe, Masanobu Yamamoto, John Farrell, Martin Frank, Peter Kubik, Wilfried Jokat, Yngve Kristoffersen
NATURE, 441, 7093, 601, 605, Jun. 2006, [Peer-reviewed]
English, Scientific journal

Distribution and sources of organic matter in surficial sediments on the shelf and slope off Tokachi, western North Pacific, inferred from C and N stable isotopes and C/N ratios
T Usui, S Nagao, M Yamamoto, K Suzuki, Kudo, I, S Montani, A Noda, M Minagawa
MARINE CHEMISTRY, 98, 2-4, 241, 259, Feb. 2006, [Peer-reviewed]
English, Scientific journal

A salinity-related occurrence of a novel alkenone and alkenoate in Late Pleistocene sediments from the Japan Sea
Kazuho Fujine, Masanobu Yamamoto, Ryuji Tada, Yoshiki Kido
ORGANIC GEOCHEMISTRY, 37, 9, 1074, 1084, 2006, [Peer-reviewed]
English, Scientific journal

Late Quaternary variation of lignin composition in core MD0-12421 off central Japan, NW Pacific
M Yamamoto, Y Ichikawa, Y Igarashi, T Oba
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY, 229, 3, 179, 186, Dec. 2005, [Peer-reviewed]
English, Scientific journal

Monsoon related changes in sea surface productivity and water column denitrification in the Eastern Arabian Sea during the last glacial cycle
VK Banakar, T Oba, AR Chodankar, T Kuramoto, M Yamamoto, M Minagawa
MARINE GEOLOGY, 219, 2-3, 99, 108, Aug. 2005, [Peer-reviewed]
English, Scientific journal

Carbon isotope signatures of bacterial 28-norhopanoic acids in Miocene-Pliocene diatomaceous and phosphatic sediments
M Yamamoto, H Naraoka, R Ishiwatari, S Ogihara
CHEMICAL GEOLOGY, 218, 1-2, 117, 133, May 2005, [Peer-reviewed]
English, Scientific journal

Combined use of delta C-14 and delta C-13 values to trace transportation and deposition processes of terrestrial particulate organic matter in coastal marine environments
S Nagao, T Usui, M Yamamoto, M Minagawa, T Iwatsuki, A Noda
CHEMICAL GEOLOGY, 218, 1-2, 63, 72, May 2005, [Peer-reviewed]
English, Scientific journal

Equatorward shift of the subarctic boundary in the northwestern Pacific during the last deglaciation
M Yamamoto, R Suemune, T Oba
GEOPHYSICAL RESEARCH LETTERS, 32, 5, L05609, Mar. 2005, [Peer-reviewed]
English, Scientific journal

Lipid compositions of a diatom Chaetoceros pseudocurvisetus in three different life forms
Yamamoto Masanobu, Kuwata Akira, Maruyama Akihiko, Higashihara Takanori
Researches in organic geochemistry, 20, 7, 13, The Japanese Association of Organic Geochemists, 2005, [Peer-reviewed]
Japanese, Scientific journal, Lipids were analyzed for three different life forms of a marine planktonic diatom, Chaetoceros pseudocurvisetus, cultured in different nutrient media, in order to examine the influence of nutrient deficiency to the variation of the lipid distribution. TLC-FID and GC-MS analyses show large differences in lipid composition between the vegetative cell (VC) cultured in a nitrate-rich medium and the resting spore (RS) and resting cell (RC) cultured in nitrate-poor media. TLC-FID profiles of total lipids showed that triacylglycerols are abundant in the VC, whilst free fatty acids and sterols are ...

Orbital-scale anti-phase variation of sea surface temperature in mid-latitude North Pacific margins during the last 145,000 years
M Yamamoto, T Oba, J Shimamune, T Ueshima
GEOPHYSICAL RESEARCH LETTERS, 31, 16, L16311, Aug. 2004, [Peer-reviewed]
English, Scientific journal

Have the tropical Pacific ocean-atmosphere interactions behaved as a driver of centurial- to orbital-scale climate changes?" "　　　　　　　　　　　　　　　
Yamamoto, M
Global Environmental Change in the Ocean and on Land (eds. Shiyomi, M., et al.), Terrapub (2004)., 265, 278, 2004, [Peer-reviewed]
English

第三紀海成珪質堆積岩中のホパン酸-おもなホパン酸と28-ノルホパン酸のGC/MSによる解析-
山本 正伸
Researches in Organic Geochemistry, 19, 31, 38, 有機地球化学会, 2004, [Peer-reviewed]
Japanese, Scientific journal

Occurrence of soupy disturbance in long piston cores from marginal seas of the Japanese Islands
YAMAMOTO Masanobu, IRINO Tomohisa, OBA Tadamichi, MURAYAMA Masafumi, IKEHARA Minoru, KODAMA Kazuto, KAWAHATA Hodaka
Journal of the Japanese Association for Petroleum Technology, 67, 6, 590, 593, 石油技術協会, 01 Nov. 2002, [Peer-reviewed]
Japanese, Scientific journal

Larval survivorship, competency periods and settlement of two brooding corals, Heliopora coerulea and Pocillopora damicornis
S Harii, H Kayanne, H Takigawa, T Hayashibara, M Yamamoto
MARINE BIOLOGY, 141, 1, 39, 46, Jul. 2002, [Peer-reviewed]
English, Scientific journal

Characteristics of organic matter in lagoonal sediments from the Great Barrier Reef
M Yamamoto, H Kayanne, M Yamamuro
GEOCHEMICAL JOURNAL, 35, 6, 385, 401, 2001, [Peer-reviewed]
English, Scientific journal

Application of nonaqueous titration to nitrogen functionality analysis for sedimentary bitumens and a crude oil
YAMAMOTO Masanobu, TAGUCHI Kazuo
Journal of the Japanese Association for Petroleum Technology, 65, 5, 469, 476, The Japanese Association for Petroleum Technology, 01 Sep. 2000, [Peer-reviewed]
English, Scientific journal, Nonaqueous titration was used for the analysis of nitrogen functionality in bitumen (solvent extract) from Neogene marine sediments and a crude oil from the Akita Basin, NE Japan. The nitrogen in bitumen or crude oil was divided into strongly basic nitrogen (SBN; pyridinic-N), weakly basic nitrogen (WBN; mostly amide-N) and nonbasic nitrogen (NBN; pyrrolic-and nonreactive-N). High SBN/bitumen-N ratio occurred in the sediment samples that were presumably deposited under high organic flux, suggesting that the abundance ratio relates to paleoproductivity. The SBN/bitumen-N (or SBN/oil-N) ratio was higher in American and Japanese crude oils than in bitumens. The difference is attributed to either their maturity difference or the fractionation during petroleum migration.

Source characterization of carbonate- and noncarbonate-associated lipids in a coral reef sediment
Yamamoto Masanobu
Researches in organic geochemistry, 15, 0, 27, 31, The Japanese Association of Organic Geochemists, Jun. 2000, [Peer-reviewed]
English, Scientific journal, A newly developed method was employed for separately extracting carbonate- and noncarbonate-assciated lipids. The sample examined was a lime mud from the inner Great Barrier Reef. Unsaturated n-fatty acids and phytol were enriched in the carbonate fraction, indicating that the carbonate-associated organic matter was derived primarily from marine algae. In contrast, saturated n-fatty acids, n-heptadecane, labdane and C_<25:1> highly branched isoprenoid alkene were enriched in the noncarbonate fraction, indicating that the source of the noncarbonate-associated organic matter includes higher p...

珪藻の生物地球化学とその古海洋学的応用　　　　　　　　　　　　　　　
山本正伸, 渡辺真人, 三田直樹, 東原直規, 丸山明彦, 山室真澄, 田中裕一郎
地調月報, 51, 205, 216, May 2000, [Peer-reviewed]
Japanese, Scientific journal

Physiological responses of lipids in Emiliania huxleyi and Gephyrocapsa oceanica (Haptophyceae) to growth status and their implications for alkenone paleothermometry
M Yamamoto, Y Shiraiwa, Inouye, I
ORGANIC GEOCHEMISTRY, 31, 9, 799, 811, 2000, [Peer-reviewed]
English, Scientific journal

Source characterization of carbonate- and noncarbonate-associated lipids in a coral reef sediment.　　　　　　　　　　　　　　　
Researches in Organic Geochemistry, 15, 13, 17, 2000, [Peer-reviewed]
English, Scientific journal

Late Quaternary records of organic carbon, calcium carbonate and biomarkers from Site 1016 off Point Conception, California margin.　　　　　　　　　　　　　　　
ODP Scientific Results, 167, 183, 194, 2000, [Peer-reviewed]
English, Scientific journal

Bioaccumulation of Diethylhexyl and Dibutil Phtalates by a Diving Duck, Aythya fuligula
YAMAMURO Masumi, TANAKA Itaru, YAMAMOTO Masanobu, ARINOBU Tetsuya
Japan journal of water pollution research, 23, 3, 168, 172, Japan Society on Water Environment, 2000, [Peer-reviewed]
Japanese, Scientific journal, Bioaccumulation of di-2-ethylhexyl phtalate (DEHP) and di-n-butyl phtalate (DBP) by a wintering diving duck, Aythya fuligula, was studied by a conventional analysis modified to minimize contamination. The 0.061 μg · g^-1 for DEHP and the 0.041 μg · g^-1 for DBP were detected in a blank sample throughout whole procedure. Added DEHP and DBP were recovered at 105.2% and 106.3%, respectively. Trophic level of A. fuligula was examined using carbon and nitrogen stable isotope ratios. Nitrogen stable isotope ratios suggested that organic component of the liver of A. fuligula was changed with its food bivalve, Corbicula japonica, by 70 days after duck's arrival. Mean concentrations of DEHP and DBP on basis of fat in the livers of ducks and the flesh of C. japonica were 332μg · g^-1 and 7.51μg · g^-1 for DEHP, and 12.1μg · g^-1 and 6.88μg · g^-1 for DBP, respectively. Concentrations of DEHP in the livers of ducks increased towards the middle of December 1994, and decreased afterwards, suggesting that both bioaccumulation and decomposition of DEHP occurred in the liver of ducks. Increase of DEHP concentrations towards the middle of December 1994 was attributed to the backflow of saline water from urbanized area, because carbon isotope ratios and the concentrations of DEHP in the liver of ducks showed positive correlation.

Alkenone paleothermometry and its application to paleoceanography
YAMAMOTO Masanobu
地球化学, 33, 3, 191, 204, The Geochemical Society of Japan, 25 Aug. 1999, [Peer-reviewed]
Japanese, Scientific journal, Alkenone paleothermometry has been used for generating late Quaternary records of sea surface temperature from deep-sea core sediments. This paper summarizes its principles, applications, problems and future. A critical problem comes from culture experiments of Emiliania huxleyi and Gephyrocapsa oceanica. The results indicate large variations in the U^<K'>_<37>-temperature relationship among different species or strains. Even single strains show variations in U^<K'>_<37> in different growth phases and culture conditions. These suggest that some physiological or environmental factor, in addi...

Petroleum nitrogen compounds : A sensitive indicator of petroleum migration(Taguchi Prize honored in 1997)
Yamamoto Masanobu
Researches in organic geochemistry, 14, 0, 1, 2, The Japanese Association of Organic Geochemists, 30 Jun. 1999, [Peer-reviewed]
English, Scientific journal, Petroleum migration is one of the key processes for the formation of oil fields. To understand the process, it is necessary to find the tools to assess the direction and distance of petroleum migration (secondary migration) and the degree of the fractionation of oil compositions during the migration. Recently nitrogen compounds became a useful tool to indicate the degree of the fractionation. This tool was proposed, and was first applied to the Sarukawa Oil Field, Japan, by Yamamoto (1992).

東北日本新第三系石油根源岩の堆積と古海洋環境変動
山本 正伸, 渡部 芳夫, 渡辺 真人
地質調査所月報, 50, 5, 361, 376, 経済産業省産業技術総合研究所地質調査所, Jun. 1999, [Peer-reviewed]
Japanese, Research institution

秋田県矢島地域新第三系堆積岩の各種結合態バイオマーカーの組成とその起源
山本 正伸
地質調査所月報, 50, 5, 329, 359, 経済産業省産業技術総合研究所地質調査所, Jun. 1999, [Peer-reviewed]
Japanese, Research institution

Organic geochemistry and palynology of Lower Cretaceous Zuunbayan oil shales,Mongolia
Masanobu Yamamoto, Bat-erdene Delegiin, Ulziikhishig Pureyiin
Bulletin Geological Survey of Japan, 49, 6, 257, 274, 経済産業省産業技術総合研究所地質調査所, Jun. 1998, [Peer-reviewed]
English, Research institution

Source rock characteristics and depositional environment of Lower Cretaceous Dsunbayan oil shales, Mongolia
YAMAMOTO Masanobu, BAT-ERDENE Delegiin, ULZIIKHISHIG Pureyiin, WATANABE Yoshio, TAKEDA Nobuyori, KAJIWARA Yoshiteru, NAKAJIMA Terumasa
Journal of the Japanese Association for Petroleum Technology, 63, 3, 239, 250, The Japanese Association for Petroleum Technology, May 1998, [Peer-reviewed]
Japanese, Scientific journal, Elemental analyses, Fischer assay pyrolysis, Rock-Eval pyrolysis and biomarker analyses were conducted for twenty-six lacustrine oil shales from the Lower Cretaceous Dsunbayan Group, Mongolia.
The Dsunbayan oil shales show large variations of organic carbon content (1.7-21.3wt%) and oil yield (0.3-11.8 wt%). A Rock-Eval pyrolysis shows that immature Type I kerogen dominates in these samples. Biomarker compositions show that major source organisms of the Dsunbayan oil shale were an autotrophic prokaryote such as a cyanobacterium, nonmarine algae, terrestrial higher plants, heterotrophic bacteria and bacterivorous ciliates.
Good correlations exist among organic carbon content, oil yield, bitumen content and n-heptadecane anomaly {2×n-C₁₇/(n-C₁₆+n-C₁₈)n-alkane ratio}. The samples with high n-heptadecane anomaly are rich in β-carotane, which suggests that the degree of bottom water anoxia controlled organic carbon content and oil yield, and was related to the contribution of an autotrophic prokaryote which sourced dominant n-heptadecane.
High C/S ratio and little sulfur compound in the Dsunbayan oil shales indicate that they were deposited in a freshwater environment. The tropical-subtropical climate promoted thermal stratification and bottom water anoxia in the freshwater lakes. The degree of development of bottom-water anoxia was likely controlled by nutrient supply from the surrounding area.

A simple estimation of shale oil content by thermogravimetry
YAMAMOTO Masanobu, SUZUKI Yuichiro, ENOMOTO Minoru, KAJIWARA Yoshiteru, TAKEDA Nobuyori
Journal of the Japanese Association for Petroleum Technology, 63, 2, 158, 164, The Japanese Association for Petroleum Technology, Mar. 1998, [Peer-reviewed]
Japanese, Scientific journal, A thermogravimetric analysis (TGA) and a Rock-Eval pyrolysis (RE) were applied to estimating the shale oil content (oil yield) in 26 oil shales from the Dsunbayan Group, Mongolia.
The weight loss during 211-505°C (WL₂-WL₁) by TGA and the generation potential (S₁+S₂) of RE are well correlated with the Fischer assay (FA) oil yield, with the following formulae, respectively.
WL₂-WL₁ (wt%)=0.720×{FA oil yield (wt%)}+2.55
S₁+S₂ (mg/g)=12.4×{FA oil yield (wt%)}-1.49
The oil yields estimated from TGA weight loss and RE generation potential both have small deviations (mostly within 1wt%) from the FA values. These estimations can be effectively applied as easy and inexpensive methods to estimate oil yields of large number of oil shale samples.

Late Quatemary record of biomarkers from ODP Leg 167, Sites 1014 and 1016, California margin
Yamamoto Masanobu, Yamamuro Masumi, Tanaka Yuichiro, Tada Ryuji, Hendy Ingrid L., Kennett James P.
Annual Meeting of the Geological Society of Japan, 1998, 136, 136, The Geological Society of Japan, 1998
Japanese

Pliocene carbonate accumulation along the California margin
AC Ravelo, M Lyle, Koizumi, I, JP Caulet, E Fornaciari, A Hayashida, F Heider, J Hood, S Hovan, T Janecek, A Janik, R Stax, M Yamamoto
PALEOCEANOGRAPHY, 12, 6, 729, 741, Dec. 1997, [Peer-reviewed]
English, Scientific journal

パラオ諸島サンゴ礁堆積物の元素・脂質組成
山本 正伸, 山室 真澄, 茅根 創
地質調査所月報, 48, 2, 79, 92, 経済産業省産業技術総合研究所地質調査所, Feb. 1997, [Peer-reviewed]
Japanese, Research institution

Molecular palaeontology of the earliest Danian at Geulhemmerberg (the Netherlands)
M Yamamoto, K Ficken, M Baas, HJ Bosch, JW deLeeuw
GEOLOGIE EN MIJNBOUW, 75, 2-3, 255, 267, 1996, [Peer-reviewed]
English, Scientific journal

Geochemistry and paleoceanography of the Onnagawa diatomaceous sediments
WATANABE Yoshio, YAMAMOTO Masanobu, WATANABE Mahito
Journal of the Japanese Association for Petroleum Technology, 60, 1, 15, 26, The Japanese Association for Petroleum Technology, Jan. 1995, [Peer-reviewed]
Japanese, Scientific journal, In order to assess the hydrocarbon potential of the Middle Miocene (10-12Ma) Onnagawa diatomaceous sediments, outcrop samples from seven sites in the Aomori and Akita Prefectures were examined for the distribution of their major and minor elements. Three factors optimal for the good source rock generation, i. e., supply of biogenous materials, small dilution effect by terrigenous detrius, and anoxic bottom water condition, were extracted by multivariate statistical analyses. Spatial distributions of these factors indicate source facies developed in the central deep part of the basin, which was kept stagnant by restricted circulation of sea water. During 10 to 9Ma, paleoceanic condition changed drastically due to the initiation of localized upwelling.

Molecular geochemical approach to the Paleoceanographic assessment of Neogene sediments of Yashima area, Akita Basin, Japan
YAMAMOTO Masanobu, WATANABE Yoshio
Journal of the Japanese Association for Petroleum Technology, 60, 1, 27, 38, The Japanese Association for Petroleum Technology, Jan. 1995, [Peer-reviewed]
English, Scientific journal, Specific source marker compounds were analyzed for solvent extracts from the Onnagawa, Funakawa and Tentokuji Formations, Yashima, Akita, NE Japan.
Relative abundances of higher plant markers, n-C₂₇ alkane, n-C₂₈ alkanoic acid and ω-hydroxy-C₂₂ alkanoic acid; to algal derived compounds increase upward through the Funakawa Formation, indicating the rapid increase of land plant input associated with the increase of detrital matter during the deposition of the Funakawa Formation. Dinosteranes as specific compounds of dinoflagellates are more abundant in the lower part of the Onnagawa and the Funakawa Formations than in the middle and upper parts of the Onnagawa and the Tentokuji Formations. C₂₅ highly branched isoprenoid (HBI) alkane as a specific compound of diatoms is abundant in the Onnagawa Formation, while less abundant in the Funakawa and Tentokuji Formations. The negative behavior of C₂₅ HBI alkane/n-C₂₁ alkane and dinosterane/4-desmethylsterane ratios through the Onnagawa Formation probably reflects the changes in primary producers likely due to the changes of nutrient silica concentration of surface water. The high dinosterane/4-desmethylsterane ratio in the Tentokuji Formation seems to reflect the increase of coastal dinoflagellates under the influence of riverine water inflow. An increase of hopane/sterane ratio in the Funakawa Formation probably reflects the increase of aerobic bacterial activity during early diagenesis resulted from bottom water oxygenation in this period.

DIRECT ANALYSIS OF LAMINATED DOLOMITE AND ZIRCON BY LASER-ABLATION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY
N IMAI, M YAMAMOTO
MICROCHEMICAL JOURNAL, 50, 3, 281, 288, Dec. 1994, [Peer-reviewed]
English, Scientific journal

堆積盆モデル評価による炭化水素資源ポテンシャル--新第三系女川根源岩相の堆積環境
渡部 芳夫, 山本 正伸, 今井 登
地質調査所月報, 45, 8, 509, 525, 経済産業省産業技術総合研究所地質調査所, Sep. 1994, [Peer-reviewed]
Japanese, Research institution

中新統女川層珪藻質岩中のダイノステランと表層水栄養塩環境
山本 正伸, 渡部 芳夫, 渡辺 真人
地質調査所月報, 45, 8, 527, 530, 経済産業省産業技術総合研究所地質調査所, Sep. 1994, [Peer-reviewed]
Japanese, Research institution

ESR STUDY OF RADIATION CENTERS AND THERMAL-BEHAVIOR IN CHERT
N IMAI, K SHIMOKAWA, M YAMAMOTO
QUATERNARY SCIENCE REVIEWS, 13, 5-7, 641, 645, 1994, [Peer-reviewed]
English, Scientific journal

Preliminary report on geochemistry of Lower Cretaceous Dsunbayan oil shales, eastern Mongolia
YAMAMOTO M
Bulletin of the Geological Survey of Japan, 44, 11, 685, 691, 経済産業省産業技術総合研究所地質調査所, Nov. 1993, [Peer-reviewed]
Japanese, Scientific journal

FRACTIONATION OF AZAARENES DURING OIL MIGRATION
M YAMAMOTO
ORGANIC GEOCHEMISTRY, 19, 4-6, 389, 402, Dec. 1992, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

BASIC NITROGEN-COMPOUNDS IN BITUMEN AND CRUDE OILS
M YAMAMOTO, K TAGUCHI, K SASAKI
CHEMICAL GEOLOGY, 93, 1-2, 193, 206, Nov. 1991, [Peer-reviewed], [Lead author, Corresponding author]
English, Scientific journal

Nitrogen compounds in bitumen from sedimentary rocks
Yamamoto M, Taguchi K, Sasaki K
Researches in organic geochemistry, 7, 0, 55, 57, The Japanese Association of Organic Geochemists, Apr. 1990, [Peer-reviewed], [Lead author]
Japanese, Scientific journal

Preliminary results of Late Holocene environmental reconstruction of the western Arctic Ocean
山本正伸, 清家弘治, POLYAK L., GEMERY L., JOE Y.J., 内田翔馬, 小林稔, 小野寺丈尚太郎, 村山雅史, 岩井雅夫, 山本裕二, JORDAN R., 山田桂, 堀川恵司, 朝日博史, 安藤卓人, 鈴木健太, 加三千宣, 永淵修, DAVID L., DAVID L., SZAREK R., 菅沼悠介, 大森貴之, 日本地球化学会年会要旨集(Web), 70th, 2023

千葉複合セクションのn-アルカン分析による海洋酸素同位体ステージ19の陸上気候・植生変動復元
梶田 展人, 関 宰, 山本 正伸, 大河内 直彦, 岡田 誠, 羽田 裕貴, 菅沼 悠介, 日本地球化学会第69回年会講演要旨集, Nov. 2022
Japanese, Summary national conference

A 1.46-million-year record of atmospheric CO₂ from sedimentary leaf wax in the Bay of Bengal
山本正伸, CLEMENS Steven, 関宰, 土屋優子, HUANG Yongsong, 大石龍太, 阿部彩子, 日本地球惑星科学連合大会予稿集(Web), 2022, 2022

モンゴル南東部の中上部ジュラ系‐下部白亜系湖成層の堆積年代と堆積環境
安藤寿男, 長谷川精, 長谷部徳子, ICHINNOROV N, 太田亨, 長谷川卓, 山本正伸, LI G, ERDENETSOGT B‐O, HEIMHOFER U, 日本古生物学会年会講演予稿集, 2018, 26, 22 Jun. 2018
Japanese

モンゴル年縞湖成層に記録される白亜紀中期“超温室期”の太陽活動周期の気候変動
長谷川精, 安藤寿男, 勝田長貴, 村木綏, ICHINNOROV N, 村山雅史, 山本鋼志, 太田亨, 長谷川卓, 山本正伸, 長谷部徳子, HEIMHOFER U, 日本堆積学会大会プログラム・講演要旨, 2018, 21‐22, 25 Mar. 2018
Japanese

モンゴルの年縞湖成層から読み解く白亜紀中期“超温室期“の十年~千年周期気候変動と太陽活動の気候影響
長谷川精, 安藤寿男, 勝田長貴, 村木綏, ICHINNOROV Niiden, 村山雅史, 山本鋼志, 太田亨, 長谷川卓, 山本正伸, 長谷部徳子, HEIMHOFER Ulrich, 池田昌之, 西本昌司, 山口浩一, 阿部文雄, 多田隆治, 日本地球惑星科学連合大会予稿集(Web), 2018, ROMBUNNO.MIS10‐01 (WEB ONLY), 2018
Japanese

別寒辺牛湿原泥炭コアのミズゴケセルロース酸素同位体比を用いた過去2000年間の古気候復元
櫻井弘道, 山本正伸, 関宰, 大森貴之, 佐藤友徳, 日本地球惑星科学連合大会予稿集(Web), 2018, ROMBUNNO.MIS01‐P06 (WEB ONLY), 2018
Japanese

ボルネオでの泥炭コアリング　　　　　　　　　　　　　　　
山本正伸, PALEO, 5, 1, 13, 01 Apr. 2017
Japanese, Report research institution

別寒辺牛湿原泥炭コアのミズゴケセルロース酸素同位体比を用いた過去2000年間の古気候復元
櫻井弘道, 山本正伸, 関宰, 大森貴之, 日本地球惑星科学連合大会予稿集(Web), 2017, ROMBUNNO.MIS23‐P12 (WEB ONLY), 2017
Japanese

ボルネオ泥炭中微粒炭量からみた過去6000年間の西部熱帯太平洋乾湿変動
山本正伸, 菊池隼史, 櫻井弘道, 林竜馬, 関宰, 大森貴之, SULAIMAN Abdullah, BIN SHAARI Hasrizal, MELLING Lurie, 日本地球惑星科学連合大会予稿集(Web), 2017, ROMBUNNO.MIS06‐06 (WEB ONLY), 2017
Japanese

Exp. 353 Indian Monsoon Rainfall (2014/11/29〜2015/1/29、JR)インド夏季モンスーンの復元　　　　　　　　　　　　　　　
臼井洋一, 浦本豪一郎, 山本正伸, 安藤卓人, NEWS, 9, 4, 1, 01 Apr. 2016
Japanese, Report research institution

インドモンスーン復元のためのベンガル湾掘削(IODP Exp.353)
山本正伸, 臼井洋一, 浦本豪一郎, 安藤卓人, CLEMENS Steven, WOLFGANG Kuhnt, LEVAY Leah, 日本地球惑星科学連合大会予稿集(Web), 2016, ROMBUNNO.MIS16‐P01 (WEB ONLY), 2016
Japanese

International ocean discovery program expedition 353 preliminary report Indian Monsoon Rainfall
Steven C. Clemens, Wolfgang Kuhnt, Leah J. LeVay, Pallavi Anand, Takuto Ando, Milos Bartol, Clara T. Bolton, Xuan Ding, Karen Gariboldi, Liviu Giosan, Edmund C. Hathorne, Yongsong Huang, Priyank Jaiswal, Sunghan Kim, John B. Kirkpatrick, Kate Littler, Gianluca Marino, Philippe Martinez, Dinesh Naik, Aditya Peketi, Stephen C. Phillips, Marci M. Robinson, Oscar E. Romero, Netramani Sagar, Katie B. Taladay, Samuel N. Taylor, Kaustubh Thirumalai, Goichiro Uramoto, Yoichi Usui, Jiasheng Wang, Masanobu Yamamoto, Liping Zhou, Integrated Ocean Drilling Program: Preliminary Reports, 353, 1, 46, Apr. 2015
English

南極周極流・ウェッデルジャイアと海氷移流のダイナミクスの解明を目指して
池原実, 関宰, 井尻暁, 佐藤暢, 山本正伸, 大河内直彦, 岡崎裕典, 松崎琢也, 日本地球惑星科学連合大会予稿集(Web), 2015, ROMBUNNO.MIS21‐P01 (WEB ONLY), 2015
Japanese

Terrestrial paleoenvironments during the mid-Cretaceous reconstructed from the continuous lacustrine strata in Southeast Mongolia
Ando H., Hasegawa H., Ohta T., Hasegawa T., Yamamoto M., Hasebe N., Murata T., shinya H., Li G., Ichinnorov N., Erdenetsogt B., Heimhofer U., Science reports of Niigata University. (Geology), 29, 14, 15, Oct. 2014
The 2nd International Symposium on Earth History of Asia 31 October – 3 November, Niigata, Japan, 新潟大学理学部, English

Temporal variation of very fine elemental carbon in sediments from the Lake Kushu in the Rebun Island during the last 3000 years
Irino Tomohisa, Nakai Yoshie, Yamamoto Masanobu, Miyazaki Yuzo, Kawamura Kimitaka, Yamada Kazuyoshi, Yonenobu Hitoshi, Abstracts of Annual Meeting of the Geochemical Society of Japan, 61, 0, 287, 287, 2014
遠距離輸送されるバイオマス燃焼起源物質の定量を目指して，堆積物中の極細粒元素状炭素（EC）量評価のために，Thermal optical transmittance法の応用を検討した．スクロース，フミン酸，フルボ酸，フラーレンのEC・有機炭素（OC）分析を行った結果，O2雰囲気，550℃-700℃に耐えるOCも存在することが分かったので，700℃-850℃で検出されるフラクションのみをECとして定義した．この方法で，礼文島・久種湖の湖底堆積物コアから選んだ試料を，2μmを境に粗粒および細粒に分画し，それぞれの粒度画分についてEC・OC分析を行った．その結果，粗粒・細粒画分中のEC・OC変動が異なる事が分かり、粗粒ECはローカルな，細粒ECはローカル，遠方両方のバイオマス燃焼起源である可能性が示唆された．ECの細粒/粗粒比変動は大陸規模でのバイオマス燃焼変動を反映する可能性がある．, GEOCHEMICAL SOCIETY OF JAPAN, Japanese

後期更新世のグレートベースン湖の形成は熱帯由来の降雨が原因：太平洋および米国西部の水循環　　　　　　　　　　　　　　　
山本正伸, サイエンス誌に載った日本人研究者2012, 45, 45, 01 Apr. 2013
Japanese, Report research institution

Western Pacific paleoceanography and Paleoclimatology: Land-Sea linkage and variability of centennial to orbital scales
Min-Te Chen, Masanobu Yamamoto, Youbin Sun, Chris Turney, JOURNAL OF QUATERNARY SCIENCE, 27, 9, 865, 865, Dec. 2012, [Peer-reviewed]
English, Others

Latent 1,500-year climate oscillation in the Holocene,　　　　　　　　　　　　　　　
Yamamoto, M, PAGES news, 20, 2, 66-67., 20, 66, 67, Dec. 2012, [Peer-reviewed], [Invited]
English

471 Late Holocene human impact on vegetation changes around Beppu Bay in northeast Kyushu, southwest Japan based on the influx pollen data dated by a wiggle-matching
Shimada Misaki, Takahara Hikaru, Kuwae Michinobu, Yamamoto Masanobu, Ikehara Ken, Irino Tomohisa, Takemura Keiji, Sagawa Takuya, Sakamoto Tatsuhiko, Ikehara Minoru, Takeoka Hidetaka, 日本花粉学会会誌, 58, 212, 213, 23 Aug. 2012
Palynological Society of Japan, English

178 Detection and characterisation of millennial-scale vegetation and climate variability in Quaternary pollen records from East Asia -recent progress and future perspective
Hayashi Ryoma, Takahara Hikaru, Igarashi Yaeko, Kumon Fujio, Liew Ping-Mei, Yamamoto Masanobu, Kawai Sayuri, Oba Tadamichi, Irino Tomohisa, Shichi Koji, 日本花粉学会会誌, 58, 81, 82, 23 Aug. 2012
Palynological Society of Japan, English

Core top TEX86 values in the south and equatorial Pacific (vol 42, pg 94, 2011)
Sze Ling Ho, Masanobu Yamamoto, Gesine Mollenhauer, Masao Minagawa, ORGANIC GEOCHEMISTRY, 46, 55, 55, May 2012
English, Others

FT法によるモンゴル中部堆積物の堆積年代の推定
川村泰士, 長谷部徳子, 安藤寿男, 長谷川精, 長谷川卓, 太田亨, 山本正伸, フィッション・トラックニュースレター, 24, 73, 74, 30 Oct. 2011
Japanese

東シナ海における古細菌および真正細菌群集の検出と鉛直分布
片岡剛文, 入野智久, 山本正伸, 鈴木光次, 東正剛, 日本海洋学会大会講演要旨集, 2009, 185, 23 Mar. 2009
Japanese

Glacial-interglacial oceanographic variations over the past 340,000 years at the mid-latitude of southwest Pacific based on a multi-proxy approach
S. L. Ho, M. Nuita, M. Yamamoto, M. Minagawa, T. Sagawa, K. Horikawa, M. Murayama, Y. Kato, GEOCHIMICA ET COSMOCHIMICA ACTA, 72, 12, A382, A382, Jul. 2008
English, Summary international conference

East-west seesaw of sea surface temperature variation in the mid-latitude North Pacific during the last two glacial cycles　　　　　　　　　　　　　　　
Yamamoto, M, Oba, T, PAGES news, 20, 66, 67, 01 Apr. 2008, [Peer-reviewed], [Invited]
English

S-65 Environmental changes during Last Interglacial period around the Japanese Islands : comparison and integration of land and marine areas
Kumon F., Yamamoto M., Nagahashi Y., Aoike K., 日本地質学会学術大会講演要旨, 114, 34, 34, 01 Sep. 2007
The Geological Society of Japan, Japanese

S-67 Sedimentary biomarker records of climate variability in the mid-latitude North Pacific
Yamamoto Masanobu, 日本地質学会学術大会講演要旨, 114, 35, 35, 01 Sep. 2007
The Geological Society of Japan, Japanese

International Antarctic Institute project in Hokkaido University.　　　　　　　　　　　　　　　
Hondoh, T, Sugiyama, S. Aoki, S, Yamamoto, M, Sueyoshi, T, Nihashi, S, Kimura, H, Proceedings of the International Symposium Asian Collaboration in IPY2007-2008, in Tokyo, March 2007, published by National Institute of Polar Research,, 93, 99, 01 Apr. 2007
Japanese, Report research institution

十勝沖海底コア・GH02-1030の花粉群による北海道東部地域21,000年間の古植生復元　　　　　　　　　　　　　　　
五十嵐八枝子, 山本正伸, 池原研, 平成18年度研究概要報告書．地質調査総合センター速報，産業技術総合研究所地質調査総合センター, 39, 165, 171, 01 Apr. 2007
Japanese, Report research institution

GH02航海で採取された十勝沖表層堆積物中の花粉・胞群　　　　　　　　　　　　　　　
五十嵐八枝子, 山本正伸, 野田篤, 平成18年度研究概要報告書．地質調査総合センター速報，産業技術総合研究所地質調査総合センター, 39, 150, 164, 01 Apr. 2007
Japanese, Report research institution

鹿島沖海底コアに見いだされたスーピー層（ハイドレート層）とその近傍層準のバイオマーカー組成　　　　　　　　　　　　　　　
山本正伸, 「海洋炭素循環とメタンハイドレート水中に吸収された炭酸ガスの分解」に関する研究開発専門委員会報告書.．，日本学術振興会, 204, 208, 01 Apr. 2006
Japanese, Report research institution

Data report: Organic carbon and biomarker variations, sites 1237 and 1239
Chikara Abe, Masanobu Yamamoto, Toshihisa Irino, Proceedings of the Ocean Drilling Program: Scientific Results, 202, 1, 14, Feb. 2006, [Peer-reviewed]
English, Report scientific journal

南シナ海南部海底堆積物中の脂肪酸による過去15万年間の環境変動
IZAWA YOSUKE, YAMAMOTO MASANOBU, SEKI OSAMU, KAWAMURA KIMITAKA, CHEN M-T, 日本地球化学会年会講演要旨集, 53rd, 0, 168, 146, 2006
西部熱帯太平洋は地球上において重要な熱と水蒸気の貯蔵庫であり、気候変動や水循環の研究する上で重要な場所である。そこで、本研究は南シナ海南部で掘削されたMD972151コア中の脂肪酸の分析を行い、過去15万年間の分布を明らかにした。陸上高等植物起源である長鎖脂肪酸(C24,26,28)濃度は完新世よりも最終氷期最寒期(LGM)において高かった。この変動は海水準の変化が陸起源物質の流入に大きな影響を与えることを示唆した。また、LGMにおける長鎖脂肪酸の水素同位体比は海洋生物起源である短鎖脂肪酸(C16,18)よりも重い値を示した。, GEOCHEMICAL SOCIETY OF JAPAN, Japanese

S-60 Holocene 1500-year variation of the Kuroshio Current
Yamamoto Masanobu, Isono Dai, Irino Tomohisa, Murayama Masafumi, Nakamura Toshio, Kawahata Hodaka, Annual Meeting of the Geological Society of Japan, 2006, 0, 31, 31, 2006
The Geological Society of Japan, Japanese

GH02-1030コアのリグニンフェノール及び脂肪酸．　　　　　　　　　　　　　　　
稲垣正樹, 山本正伸, 池原研, 千島孤−東北日本孤会合部の海洋地質学的研究．平成16年度研究概要報告書−根室沖・日高沖海域−．地質調査総合センター速報, 33, 188, 192, 01 Apr. 2005
Japanese, Report research institution

GH02-1030コアのアルケノン古水温変動　　　　　　　　　　　　　　　
稲垣正樹, 山本正伸, 池原研, 千島孤−東北日本孤会合部の海洋地質学的研究．平成16年度研究概要報告書−根室沖・日高沖海域−．地質調査総合センター速報, 33, 185, 187, 01 Apr. 2005
Japanese, Report research institution

IODP Expedition 302, Arctic Coring Expedition (ACEX): A first look at the Cenozoic Paleoceanography of the central Arctic Ocean.　　　　　　　　　　　　　　　
Backman, J, Moran, K, McInroy, D, the IODP Expeditio, Scientists, Scientific Drilling, 1, 12, 17, 01 Apr. 2005, [Invited]
English

GH02航海で採取された十勝沖表層堆積物のリグニンフェノール組成．千島孤−東北日本孤会合部の海洋地質学的研究　　　　　　　　　　　　　　　
市川豊, 山本正伸, 平成15年度研究概要報告書−釧路沖・日高沖海域−．地質調査総合センター速報, 30, 186, 196, 01 Apr. 2004
Japanese, Report research institution

GH02-1030コアのリグニンフェノール組成（予報）　　　　　　　　　　　　　　　
稲垣正樹, 山本正伸, 千島孤−東北日本孤会合部の海洋地質学的研究．平成15年度研究概要報告書−釧路沖・日高沖海域−．地質調査総合センター速報, 30, 180, 185, 01 Apr. 2004
Japanese, Report research institution

GH02航海で採取された十勝川表層堆積物の有機炭素・全窒素の安定同位体比とC/N比（予報）．　　　　　　　　　　　　　　　
碓井敏宏, 山本正伸, 南川雅男, 千島孤−東北日本孤会合部の海洋地質学的研究．平成15年度研究概要報告書−釧路沖・日高沖海域−．地質調査総合センター速報, 30, 170, 179, 01 Apr. 2004
Japanese, Report research institution

Data Report: Organic carbon, and alkenone sea-surface temperature from Sites 1175, 1176, and 1178, Nankai Trough　　　　　　　　　　　　　　　
Yamamoto, M, Proceedings of Ocean Drilling Program, Scientific Results, 190, 196, 1, 10, 2004, [Peer-reviewed]
English, Report scientific journal

造礁サンゴ幼生２種の分散に関わる定着期間および脂質特性　　　　　　　　　　　　　　　
波利井佐紀, 灘岡和夫, 山本正伸, 茅根創, 林原毅, 岩尾研二, 2004年日本ベントス学会・プランクトン学会合同大会講演要旨集, 63, 2004

High resolution records of organic carbon and its isotopes in Core MD01-2421 off central Japan, NW Pacific, during the last 145,000 years
T Ueshima, M Yamamoto, T Oba, T Kuramoto, M Minagawa, T Irino, GEOCHIMICA ET COSMOCHIMICA ACTA, 67, 18, A502, A502, Sep. 2003
English, Summary international conference

Precession-controlled changes in alkenone sea surface temperature in Core MD01-2421 off central Japan, NW Pacific, during the last 145,000 years
M Yamamoto, J Shimamune, T Ueshima, T Oba, GEOCHIMICA ET COSMOCHIMICA ACTA, 67, 18, A552, A552, Sep. 2003
English, Summary international conference

Late quaternary variation of ligninphenols in core MD01-2421 off central Japan, NW Pacific
Y Ichikawa, M Yamamoto, T Oba, GEOCHIMICA ET COSMOCHIMICA ACTA, 67, 18, A164, A164, Sep. 2003
English, Summary international conference

十勝沖コア試料中における微生物群集構造の PCR-DGGE法による解析．　　　　　　　　　　　　　　　
鈴木聡, 片岡悠子, 山本正伸, 地質調査総合センター「千島孤−東北日本孤会合部の海洋地質学的研究 十勝沖海域」平成１４年度研究概要報告書, 184, 191, 01 Apr. 2003
Japanese, Report research institution

GH02航海で採取された十勝沖海底コアGH02-1023およびGH02-1030の有機炭素量．　　　　　　　　　　　　　　　
山本正伸, 地質調査総合センター「千島孤−東北日本孤会合部の海洋地質学的研究 十勝沖海域」平成１４年度研究概要報告書, 177, 183, 01 Apr. 2003
Japanese, Report research institution

GH02航海で採取された十勝沖表層堆積物の有機炭素量．　　　　　　　　　　　　　　　
山本正伸, 市川豊, 地質調査総合センター「千島孤−東北日本孤会合部の海洋地質学的研究 十勝沖海域」平成１４年度研究概要報告書, 170, 176, 01 Apr. 2003
Japanese, Report research institution

Nonthermal factors affecting production and unsaturation of alkenones in Emillania huxleyi and Gephyrocapsa oceanica
JM Sorrosa, M Yamamoto, Y Shiraiwa, ADVANCED RESEARCH ON PLANT LIPIDS, 133, 136, 2003
English, Report scientific journal

Data Report: Alkenone compounds and major ellement composition in late Quaternary hemipelagic sediments from ODP Site 1151 off Sanriku, northern Japan.　　　　　　　　　　　　　　　
Fujine, K, Yamamoto, M, Tada, R, Proceedings of the Ocean Drilling Program, Scientific Results, 186, 1, 12, 2003
English, Report scientific journal

西部北太平洋北緯39 度東経147度地点におけるアルケノンフラックスの評価 NH99試料について￥　　　　　　　　　　　　　　　
山本正伸, 嶋本晶文, 福原達雄, 田中裕一郎, 西村昭, 地質調査総合センター速報「海洋中の堆積物形成過程に関する研究」産業技術総合研究所．, 64, 71, 01 Apr. 2002
Japanese, Report research institution

西部北太平洋沈降粒子中のアルケノン炭素同位体組成の季節変動（予報）．　　　　　　　　　　　　　　　
山本正伸, 奈良岡浩, 地質調査総合センター速報「海洋中の堆積物形成過程に関する研究平成１２年度研究概要報告」, 112, 121, 01 Apr. 2001
Japanese, Report research institution

西部北太平洋２地点における水柱と堆積物表層におけるアルケノンフラックスの評価（予報）　　　　　　　　　　　　　　　
山本正伸, 嶋本晶文, 福原達雄, 田中裕一郎, 西村昭, 地質調査総合センター速報「海洋中の堆積物形成過程に関する研究平成１２年度研究概要報告」, 90, 111, 01 Apr. 2001
Japanese, Report research institution

Introduction: Geochemical cycles and global changes　　　　　　　　　　　　　　　
Tsunogai, S, Montani, S, Obata, H, Ono, T, Watanabe, Y, Yamamoto, M, Journal of Oceanography, 370, 647, 650, 01 Apr. 2001, [Invited]
English

沈み込み帯における有機物の輸送過程　　　　　　　　　　　　　　　
山本正伸, 月刊地球号外, 32, 96, 100, 01 Apr. 2001, [Invited]
Japanese

古海洋一次生産変動の情報をもたらす有機分子を探る
山本 正伸, 海洋, 32, 9, 618, 622, Sep. 2000, [Invited]
海洋出版, Japanese

アルケノンによる石灰質成分のフラックス算出の試み　　　　　　　　　　　　　　　
山本正伸, 地質調査所速報「海洋中の堆積物形成過程に関する研究」平成１１年度研究概要報告, 85, 89, 01 Apr. 2000
Japanese, Report research institution

Leg167：カリフォルニア縁辺海の湧昇史と古海洋学　　　　　　　　　　　　　　　
Lyle, M, 小泉格, 林田明, 丸山俊明, 多田隆治, 山本正伸, ODPニュースレター, 14, 19, 01 Apr. 1997, [Invited]
Japanese

地球環境の変遷と石油天然ガス根源岩の形成．
渡部芳夫, 山本正伸, 地質ニュース, 497, 7, 16, 01 Jun. 1995, [Invited]
Japanese

オマーンにみる原生代・石油根源岩のラミナ構造　　　　　　　　　　　　　　　
山本正伸, 鈴木祐一郎, 今井登, 梶間幹雄, 地質ニュース, 487, 口絵, 01 Apr. 1995
Japanese, Report research institution

バイオマーカーと古環境　　　　　　　　　　　　　　　
山本正伸, Science & Technonews Tsukuba, 46, 38, 40, 01 Apr. 1995, [Invited]
Japanese

パラオ諸島サンゴ礁における有機物の堆積過程とその起源　　　　　　　　　　　　　　　
山本正伸, 山室真澄, 茅根創, 月刊海洋, 27, 9, 567, 572, 01 Apr. 1995
Japanese

古海洋環境の復元：分子地球化学的アプローチの現状と課題　　　　　　　　　　　　　　　
山本正伸, 地質ニュース, 495, 15, 24, 01 Apr. 1995, [Invited]
Japanese

Mongol Aitai:Rebuilt mountain range in the Steppe.,
Nkajima Terumasa, Watanabe Yoshio, Harayama Satoru, Yamamoto Masanobu, Journal of the Geological Society of Japan, 99, 5, ix, x, 15 May 1993, [Peer-reviewed]
The Geological Society of Japan, Japanese

東北日本女川堆積盆の堆積環境．　　　　　　　　　　　　　　　
渡部芳夫, 山本正伸, 今井登, 「資源評価のための三次元モデリング手法に関する研究」最終年度報告書．地質調査所, 15, 36, 01 Apr. 1993
Japanese, Report research institution

東北日本中新統女川層珪藻質岩の有機分子組成と古海洋環境．　　　　　　　　　　　　　　　
山本正伸, 渡部芳夫, 「資源評価のための三次元モデリング手法に関する研究」最終年度報告書．地質調査所, 101, 129, 01 Apr. 1993
Japanese, Report research institution

地球環境の変遷と炭化水素根源岩の形成　　　　　　　　　　　　　　　
渡部芳夫, 山本正伸, 「炭化水素鉱床の成因と同ポテンシャルの予測技術に関する研究動向」平成３年度工業技術院特別研究推進費調査報告書, 32, 49, 01 Apr. 1992
Japanese, Report research institution

使える探査技術”石油移動指標”の開発の現状と課題所．　　　　　　　　　　　　　　　
山本正伸, 「炭化水素鉱床の成因と同ポテンシャルの予測技術に関する研究動向」平成３年度工業技術院特別研究推進費調査報告書, 01 Apr. 1992
Japanese, Report research institution

Mayer, L.A. (1991): Extraction of high-resolution carbonate data for paleoclimate reconstraction. Nature, 352, 148-150(EARTH SCIENCE TODAY)
山本 正伸, 地球科學, 46, 1, 85, 85, 25 Jan. 1992
The Association for the Geological Collaboration in Japan (AGCJ), Japanese

秋田県能代・鷹巣地域の女川層（岩谷層）珪質岩類のバイオマーカー組成　　　　　　　　　　　　　　　
山本正伸, 「資源評価のための三次元モデリング手法に関する研究」第一次中間報告書．地質調査所, 42, 54, 01 Apr. 1990
Japanese, Report research institution

青森県鯵ヶ沢町中村川地域の地質と大童寺層泥質岩中の有機物 −特に，C25にピークを持つノルマルアルカン分布パターンについて　　　　　　　　　　　　　　　
佐々木清隆, 山本正伸, 田口一雄教授退官記念論文集「石油鉱床学の諸問題」, 223, 239, 01 Mar. 1986, [Invited]
Japanese

北極環境研究の長期構想　　　　　　　　　　　　　　　
北極環境コンソーシアム編
北極環境コンソーシアム, 2014

地球と宇宙の化学事典　　　　　　　　　　　　　　　
日本地球化学会編
朝倉書店, 2012

地球温暖化の科学　　　　　　　　　　　　　　　
北海道大学大学院環境科学院編
北海道大学出版会, 2007

有機地球化学　　　　　　　　　　　　　　　
石渡良志, 山本正伸編
培風館, 2004

自然科学実験（空中写真および水分析）　　　　　　　　　　　　　　　
北海道大学

地球惑星科学実験（スメアスライド観察）　　　　　　　　　　　　　　　
北海道大学理学部

地球環境学　　　　　　　　　　　　　　　
北海道大学理学部

地球環境と北極域の科学　　　　　　　　　　　　　　　
北海道大学

古気候を解明する　　　　　　　　　　　　　　　
北海道大学

南極学特論　　　　　　　　　　　　　　　
北海道大学大学院共通

古環境学基礎論　　　　　　　　　　　　　　　
北海道大学大学院環境科学院

有機地球化学特論　　　　　　　　　　　　　　　
北海道大学大学院環境科学院

古気候学特論　　　　　　　　　　　　　　　
北海道大学大学院環境科学院

Climate instability and tipping cascade: examining the climate risks posed by global warming
Grants-in-Aid for Scientific Research
01 Apr. 2024 - 31 Mar. 2029
関 宰, 板木 拓也, 山本 正伸
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (S), Hokkaido University, 24H00074

Reconstruction of atmospheric carbon dioxide conentrationover the past ten million years
Grants-in-Aid for Scientific Research
01 Apr. 2024 - 31 Mar. 2028
山本 正伸, 吉森 正和, 阿部 彩子, 関 宰, 入野 智久, 岩崎 晋弥
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 24H00256

過去350万年間にわたる極域気候の基準データ決定版の創生：アイスコアを超えて
科学研究費助成事業
28 Jun. 2024 - 31 Mar. 2027
関 宰, 山本 正伸
日本学術振興会, 挑戦的研究(萌芽), 北海道大学, 24K21555

Reconstruction of Pacific Ocean dissolved oxygen concentrations over the past six million years: Toward understanding ocean carbon storage
Grants-in-Aid for Scientific Research
28 Jun. 2024 - 31 Mar. 2026
山本 正伸, 臼井 朗, 柏原 輝彦, 長谷川 精, 小田 啓邦
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Research (Exploratory), Hokkaido University, 24K21556

+5℃まで温暖化が進行する過程における南極氷床融解のふるまいと特性の解明
科学研究費助成事業
01 Apr. 2020 - 31 Mar. 2025
関 宰, 山本 正伸, 菅沼 悠介, 池原 実
南極氷床が温暖化に対して敏感であることが明らかになり、温暖化の進行による海面上昇に対する危機感が高まっている。最新のIPCC特別報告書では将来の海面上昇予測が大幅に上方修正され、最も温暖化が進行するシナリオによれば300年後に海面が数メートル上昇するという。この上方修正は南極氷床融解量の見積もりの変更によるものであり、現在「温暖化が進行した場合にどの段階でどのような速度で南極氷床融解が進行しうるのか？」が海面上昇予測における核心的な問いになっている。氷床の応答時間は長く、その特性の本質的な理解にはより温暖な気候状態における長期間の氷床変動を調べる必要があり、今後の予測に関しては不確かさが非常に大きい。本研究では、国際深海科学掘削計画（IODP）において西南極ロス海で昨年掘削された最新の海底堆積物コアを用い、現在より全球平均気温が+1℃から+5℃（海面が+5から+40mまで上昇）温暖であった時代における南極氷床の融解過程を100年スケールの解像度で復元し、+5℃まで温暖化が進行する過程における南極氷床融解の特性を明らかにする。
中期鮮新世温暖期（約330-300万年前）および中期中新世気候最適期（約1600万年前前後の数万年間）を対象とする。最新の地球化学的手法を駆使し、海水温や南極氷床の変動の復元および氷床の融解地域の特定を行い、氷床の大規模かつ不可逆的な融解イベントが起こっていたのかどうか、もし起こっていたとしたらどの地域でどのように進行するのか、またそれを導く要因の解明を行う。
日本学術振興会, 基盤研究(A), 北海道大学, 20H00626

過去600万年間にわたる大気中二酸化炭素濃度と気候の相互作用の解明　　　　　　　　　　　　　　　
科学研究費補助金基盤研究（S）
Jun. 2019 - Mar. 2024
山本 正伸
日本学術振興会, Principal investigator, Competitive research funding

東アジアの古代湖「琵琶湖」の固有種成立過程の解明のための総合的研究
科学研究費助成事業
01 Apr. 2018 - 31 Mar. 2023
高橋 啓一, 百原 新, 渡辺 勝敏, 田畑 諒一, 里口 保文, 山川 千代美, 山本 正伸, 三浦 収, 林 竜馬, 大槻 達郎, 仲谷 英夫
【古地理班】地質学的観点から琵琶湖の地史研究を行ったほか，琵琶湖南湖東岸で行われたボーリング試料の堆積年代の再検討を行い，その成果を報告した（里口編，2021）．
【植生史・古気候班】琵琶湖地域での水辺の古植生の特徴を捉えるため，同時代の他の地域での比較研究を進めた．10月および11月に八王子市北浅川河床の調査を行い，10点の樹幹化石を確認し，試料を採取した．また，この場所から以前産出した樹幹化石（国立科学博物館蔵）の同定を行い，メタセコイア属であることを明らかにした．
【陸上大型動物班】琵琶湖地域から発見されている脊椎動物化石の意義を検討するために，後期更新世の化石について再検討した．例えば，ナウマンゾウでは，300か所の地点を再検討し，初出の時期がMIS 10の時代（約36～34万年前）であったとするのが妥当であるという結論に達した．また、オオツノジカの産出時代については，確かな年代を示すものは，MIS 6の時代（約13万年前）以降であり，こうした時代に淡水性の生物も日本列島に渡来した可能性を指摘した．また，マイクロウェアの研究においては，ミエゾウの化石資料からレプリカを収集した．さらに，ナウマンゾウ化石を用いてマイクロウェアの定量的な解析を行う方法を検討し，報告した（山田，2021）．
【水棲生物班】琵琶湖及び周辺地域の魚類や貝類の進化史を描き出すために，引き続き様々な分子遺伝解析を行った．魚類においては，琵琶湖のカマツカの表現型多様性パターンに関する形態比較，食性解析，集団遺伝解析から，本種における食性に関係した集団内の適応的な機能形態的多様性の拡大を明らかにし，報告した（Endo and Watanabe, 2020）．貝類については，西日本のカワニナに見られるmtDNAが琵琶湖起源であることを明らかにし，報告した（Miura et al., 2020）.
日本学術振興会, 基盤研究(B), 滋賀県立琵琶湖博物館, 18H01330

Verification of abrupt climate change in hothouse climate state from lacustrine varve record
Grants-in-Aid for Scientific Research
01 Apr. 2019 - 31 Mar. 2022
Hasegawa Hitoshi
Understanding climate variability and stability under extremely warm ‘greenhouse’ conditions in the past is essential for future climate predictions. This study examined ultra-high-resolution (seasonal- to decadal-scale) climate variability from annually laminated lacustrine deposits formed during the mid-Cretaceous in southeastern Mongolia. Inter-annual changes in lake algal productivity and micro-scale stable isotope analysis reveal a pronounced solar influence on decadal- to centennial-scale climatic variations. Ca/Ti ratios (proxy for evaporation/precipitation changes) for a ~350-kyrs interval by using XRF core scanner further indicate millennial-scale extreme drought events in inner-continental areas of mid-latitude paleo-Asia. These findings point to a previously unidentified mode of millennial-scale abrupt climate oscillations occurring under warmer ‘greenhouse’ conditions, which were possibly linked to oscillations in the strength of deep-water formation.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Kochi University, 19H04256

地球気候の本質的理解に向けた温室地球時代の海水温季節変動動態の解析
科学研究費助成事業
01 Apr. 2019 - 31 Mar. 2022
守屋 和佳, 長谷川 卓, 山本 正伸, 石村 豊穂
本研究では，地球温暖化時代の極相期の一つである白亜紀中期セノマニアン期からチューロニアン期(CTB;約9千4百万年前)に生じた海洋無酸素事変を対象として，平均古水温の緯度勾配と，古水温の季節変動幅との時系列変動を明らかにする．平均古海水温の算出に加え，海水温の季節変動幅の算出から，炭素循環擾乱イベントに対する海水温の動的応答の解析を行うことで，温室時代の気候フィードバックがどのような順序で，どのような時間スケールで生じたのかを明らかにする．2020年度は，早稲田大学現有の連続フロー型安定同位体比質量分析計を用いて，堆積物中の有機炭素および全窒素安定同位体比分析を行った．堆積物全岩試料を乾燥させ，均質に粉末化した後に脱灰し，これらを安定同位体比分析に使用した．黒色頁岩が産出する層準では，堆積物中の有機炭素含有量が20wt%を超える層準が確認され，CTBに生じた海洋無酸素事変の層準を確認した．また，海洋無酸素事変が発生した層準よりも下位の層準でも有機炭素含有量の増加を検出した．この層準は大規模な海洋無酸素事変の前駆的現象である可能性があり，今後詳細な検討を行う．有機炭素同位体比は黒色頁岩が産出する層準よりも有意に下位の層準から増加し始め，黒色頁岩層準で最大に達した．また，炭素同位体比の変化に同調して，堆積物中の炭素／窒素含有量比も大きく変化することから，海洋無酸素事変に並行して堆積物に供給される炭素の給源組成に変化が起きていたことが推測される．
日本学術振興会, 基盤研究(B), 早稲田大学, 19H02016

Relationship between Tropical Pacific Ocean-Atmosphere Interaction and Northern Hemisphere Glaciation during the late Cenozoic
Grants-in-Aid for Scientific Research
01 Apr. 2018 - 31 Mar. 2022
Sagawa Takuya
To investigate the relationship between changes in vertical temperature structure in the western tropical Pacific and global climate change, I analyzed planktonic foraminiferal shell geochemistry for three species picked from sediment core drilled in the International Ocean Discovery Program. The thickness of surface mixed layer was estimated by reconstructing vertical temperature structure from surface to subsurface for the last 4 Myr. The results suggested that the vertical temperature structure change has been associated with the meridional temperature gradient from tropics to polar region.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Kanazawa University, 18H01279

Mechanism of significant Antarctic ice sheet collapse events during the Last Interglacial
Grants-in-Aid for Scientific Research
01 Apr. 2017 - 31 Mar. 2021
Seki Osamu
During the Last Interglacial, when global mean temperatures were +1 degree C higher than pre-industrial levels, sea levels were estimated to have been +6-9 m higher than the present level. A better understanding of the dynamics of the Antarctic ice sheet during the Last Interglacial provides important insights for predicting sea-level changes in future warming scenarios. In this study, we reconstructed the ice sheet dynamics of the Wilkes Subglacial Basin Ice Sheet (WBIS) during the Last Interglacial based don analyses of neodymium isotope and beryllium in a marine sediment core (GC1407) collected near East Antarctica to reconstruct the dynamics of WBIS during the Last Interglacial. We found, for the first time, that significant WBIS retreat occurred not only in the early part of the Last Interglacial but also in the late stage of the Last Interglacial.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 17H01166

西部赤道太平洋Exp.363古環境復元（掘削航海番号：Exp. 363 種別 [JR]）　　　　　　　　　　　　　　　
IODP乗船後研究委託業務
01 Apr. 2017 - 31 Mar. 2020
山本正伸
国立研究開発法人海洋研究開発機構, Principal investigator, Competitive research funding

Seasonal temperature variability and the timing of the initial Antarctic glaciation across the climate jump at the Eocene/Oligocene boundary
Grants-in-Aid for Scientific Research
01 Apr. 2016 - 31 Mar. 2020
Moriya Kazuyoshi
We described average sea water temperature, seasonal variability in sea water temperature, and timing of the onset of the Antarctic glaciation across the Eocene/Oligocene transition. We utilized sediments obtained by the Integrated Ocean Drilling Program, Expedition 342 at off Newfoundland, Canada. Carbon and Oxygen isotope ratios of selected planktic foraminifers recovered from the sediments of the late Eocene through early Oligocene in age were analyzed. In addition to these isotope analyses, organic molecules extracted from these sediments were also analyzed on high performance liquid chromatography to identify TEX86 temperature.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Waseda University, 16H04070

長鎖脂肪酸の同位体比を用いた完新世長江下流域の乾湿および植生変動の復元　　　　　　　　　　　　　　　
新学術領域研究（研究領域提案型）公募研究
Apr. 2018 - Mar. 2020
山本 正伸
文部科学省, Principal investigator, Competitive research funding

アジアモンスーンの長期的変動に関する共同研究　　　　　　　　　　　　　　　
頭脳循環を加速する戦略的国際研究ネットワーク推進プログラム
01 Oct. 2017 - 2020
山本正伸
日本学術振興会, Principal investigator, Competitive research funding

別府湾柱状堆積物の解析にもとづく過去8000年間の太平洋十年規模変動の復元　　　　　　　　　　　　　　　
科学研究費補助金基盤研究（A）
Apr. 2016 - Mar. 2019
山本正伸
日本学術振興会, Principal investigator, Competitive research funding

Turning point between green house and ice house earths: investigation of paleothermometry from Cretaceous at Canadian Pacific Coast
Grants-in-Aid for Scientific Research
01 Apr. 2015 - 31 Mar. 2018
Hasegawa Takashi, GOTO Akiko, Haggart James W., Crampton James
Upper Campanian sequence exposed on a tidal flat around Hornby Island nearby Vancouver Island, British Columbia, Canada, was geologically surveyed. Oxygen and carbon isotopes from the samples obtained from there were analyzed.
A carbonate concretion with 2 m in the major axis was found and identified as a cold methane seep carbonate based on internal structure and carbon isotope signatures. As it was formed just on the sea bottom, the oxygen isotope values were used for paleothermometry of bottom water at depsitional depth (~200 m). Surprizing low paleotemperature as low as 8 ℃ indicates domination of cool water mass that is complarable with deep water over upper bathyal depth of middle latitude North Eastern Pacific. This paleothermometry is important for paleoceanographic reconstruction of North Eastern Pacific during late Campanian.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Kanazawa University, 15H05213

ベンガル湾Exp.353古環境復元（掘削航海番号：Exp. 353 種別 [JR]）　　　　　　　　　　　　　　　
IODP乗船後研究委託業務
01 Apr. 2015 - 31 Mar. 2018
山本正伸
国立研究開発法人海洋研究開発機構, Principal investigator, Competitive research funding

ボルネオ島泥炭掘削：過去4000年間の熱帯大気対流活動の復元　　　　　　　　　　　　　　　
科学研究費補助金基盤研究（B）海外学術
01 Apr. 2015 - 31 Mar. 2018
山本正伸
日本学術振興会, Principal investigator, Competitive research funding

Early history of NADW: proposal and verification of Pacific inflow hypothesis
Grants-in-Aid for Scientific Research
27 Jun. 2014 - 31 Mar. 2018
Hasegawa Takashi, Goto Akiko, Toyama Kotaro
Pelagic barite and carbonate-associated sulfate were extracted and their sulfur isotope values are studied from deep sea cores from various 8 deep sea core sites of the world. Expected dramatic shift as short as 1 myr discussed for sea water sulfate across 50 Ma was not observed both in the barite and CAS media. Sulfur isotope value of sea water guradually increased through 51-41 Ma. The samples that yielded both barite and CAS indicated CAS had a potential for proxy of d34S of paleo-sea water. Global sea water was homogeneous in terms of d34S through 51-47 Ma, however, north-south gradient was apparent through 45-40 Ma. Arctic Outflow water is possible candidate to explain this gradient.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Kanazawa University, 26247086

Core-drilling survey of Cretaceous lacustrine deposits in Mongolia: land-ocean linkage during OAE period on tens of thousands year scale
Grants-in-Aid for Scientific Research
01 Apr. 2013 - 31 Mar. 2016
Ando Hisao, HASEGAWA HITOSHI, OHTA TORU, YAMAMOTO MASANOBU, HASEBE NORIKO, HASEGAWA TAKASHI
Detailed cyclic stratigraphy of the lacustrine Lower Cretaceous Shinekhudag Formation distributed in Gobi desert, southeast Mongolia, is established through outcrop and three drilled core sections. In terms of radiometric age measurements by FT and U/Pb methods for zircon grains from intercalated tuffaceous layers, the depositional age of the Shinekhudag Formation can be estimated to be during 123-119 Ma (early Aptian).
Several kinds of analyses for annual varve thickness and chemical proxy in mudstone sequences, show climatic and lake-level changes controlled, respectively by solar forcing (11, 88 and 400 yrs) and orbital cycles (20, 100 and 400 kyrs). Therefore, the Shinekhudag lacustrine deposits are interpreted to record the millennial- to orbital-scale paleoclimatic changes in mid-latitude Asia during the Aptian period.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Ibaraki University, 25302011

南大洋と北極海の完新世水温変動の高時間解像度復元　　　　　　　　　　　　　　　
科学研究費補助金基盤研究（B）
01 Apr. 2013 - 31 Mar. 2016
山本正伸
日本学術振興会, Principal investigator, Competitive research funding

Detection of archaeal components in marine dissolved organic matter
Grants-in-Aid for Scientific Research
01 Apr. 2013 - 31 Mar. 2015
YAMASHITA Youhei, YAMAMOTO Masanobu
Dissolved organic matter (DOM) in the ocean constitutes one of the largest reduced carbon pools in the global carbon cycle. Bio-refractory components of DOM (RDOM) are major fraction of DOM. Marine bacterial components were found in DOM and thought to be RDOM. Archaea has recently known to be widely distributed in the ocean. Thus, it can be hypothesized that archaeal components occur in the ocean as RDOM. However, there is no evidence about occurrence of archaeal components in DOM at present.
In this study, we tried to detect glycerol dialkyl glycerol tetraethers (GDGTs) that are components of archaeal lipids in marine DOM fraction. As a result, we detect the GDGTs from surface to deep DOM at the western North Pacific and the Arctic oceans. This finding implies that archaeal components occur ubiquitously in marine DOM.
Japan Society for the Promotion of Science, Grant-in-Aid for Challenging Exploratory Research, Hokkaido University, 25550001

堆積物中セルロース酸素同位体比分析による古気候復元　　　　　　　　　　　　　　　
科学研究費補助金萌芽研究
01 Apr. 2013 - 31 Mar. 2015
山本正伸
日本学術振興会, Principal investigator, Competitive research funding

Mechanism driving depleted anchovy and sardine abundance and their amplitude/periodicity changes on decadal timescales during the Medieval Warm Period
Grants-in-Aid for Scientific Research
01 Apr. 2010 - 31 Mar. 2014
KUWAE Michinobu, YAMAMOTO Masanobu, NAKAMURA Yugo, TAKEMURA Keiji, MORIYA Kazuyoshi, TANI Yukinori
To elucidate how decadal-scale variability of Japanese sardine stock will change in relation to global ocean warming, we examined changes in amplitude of sardine decadal variability and changes in peleotemperature and paleoploductivity around Medieval Climate Anomaly as an analogue for their response to climate change. Sardine abundance was reconstructed from coastal marine sediments of Beppu Bay, Japan. The record showed centennial-scale variability (250-300 years) and no clear response of sardine to climate changes corresponding to Medieval Climate Anomaly/Little Ice Age transitions in the western North Pacific. Rather, centennial variability of sardine abundance showed a similar pattern to basin-wide climate variability found in the reconstructed PDO index in the North America and the abnormal snow index in the East Asia. It is possible that one of driving factors of the centennial variations in sardine abundance is prey abundance in the western North Pacific.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Ehime University, 22340155

別府湾海底コアの解析にもとづく10年スケール気候変動・レジームシフトの歴史的変遷の解明　　　　　　　　　　　　　　　
研究助成
01 Apr. 2010 - 31 Mar. 2013
山本正伸
三井物産環境基金, Principal investigator, Competitive research funding

バイオマーカー水素同位体比を用いた過去１５万年間の熱帯太平洋大気対流活動の復元　　　　　　　　　　　　　　　
科学研究費補助金基盤研究（A）
01 Apr. 2007 - 31 Mar. 2012
山本正伸
日本学術振興会, Principal investigator, Competitive research funding

Terristrial humidity increase during mid-Cretaceous : Cretaceous research in Mongolia for understanding of greenhouse Earth system
Grants-in-Aid for Scientific Research
2009 - 2011
ANDO Hisao, HASEGAWA Takashi, OHTA Toru, YAMAMOTO Masanobu, HASEBE Noriko, TAKAHASHI Masamichi, HASEGAWA Hitoshi
The lacustrine deposits of the mid-Cretaceous Shinekhudag Formation and middle Jurassic Eedemt Formation in southeast Mongolia are investigated through the following two strategy : (1) Establishment of chronostratigraphy by carbon-isotopic stratigraphy, conchostracans biostratigraphy, and fission-track age dating of intercalated tuffaceous rocks, and (2) Reconstruction of terrestrial paleoclimatic changes by cyclicity of the rhythmically alternating shale-dolomite, paleoweathering changes based on mineral and major elemental ratios, and paleotemperature changes based on organic geochemical proxy (TEX_<86>). The results reveal that these lacustrine strata record orbital-controlled paleoclimatic (precipitation and temperature) changes in inland Asia during the OAE intervals.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), Ibaraki University, 21403008

氷河期の熱帯温度の研究　　　　　　　　　　　　　　　
共同研究事業
01 Apr. 2006 - 31 Mar. 2008
山本正伸
財団法人交流協会, Principal investigator, Competitive research funding

TEX86指標を用いた過去６００万年間の北半球水温緯度勾配の復元　　　　　　　　　　　　　　　
科学研究費補助金萌芽研究
01 Apr. 2006 - 31 Mar. 2008
山本正伸
日本学術振興会, Principal investigator, Competitive research funding

Research of characteristics of riverine suspended particles released by heavy rain and their effects on coastal ecosystem
Grants-in-Aid for Scientific Research
2006 - 2008
NAGAO Seiya, YAMAMOTO Masanobu, IRINO Tomohisa, HUJITAKE Nobuhide, ARAMAKI Takahumi
石狩川河川水の懸濁態有機物の放射性炭素のδΔ14C値は年間を通じて大きな変動を示し、雪融けと降雨時には古い有機物が移動していることが明らかとなった。その変動幅は下流域<中流域<河口域<上流域の順であり、河川に供給される懸濁態の有機物は、河川流域環境や水の供給経路等の特徴と関連して変動することが考えられる。これらの結果から、沿岸域への影響評価には、雪融けと降雨時の粒子の供給量と供給機構の重要性が示唆された。
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), 18310002

陸起源有機分子を用いた融氷期東アジア水循環の高時間解像度復元　　　　　　　　　　　　　　　
科学研究費補助金基盤研究（B）
01 Apr. 2004 - 31 Mar. 2007
山本正伸
日本学術振興会, Principal investigator, Competitive research funding

Study on Accumulation and Transportation of Refractory Organic Materials in Terrestrial Area
Grants-in-Aid for Scientific Research
2003 - 2005
NAGAO Seiya, YAMAMOTO Masanobu, FUJITAKE Nobuhide, IRINO Tomohisa, KODAMA Hiroki
An important part of global organic carbon cycle is the flux of terrestrial organic carbon from the continents to the oceans. The potential importance of coastal systems in global and regional organic budgets is still unclear because of the inherent complexity and variability of rivers, estuaries and coastal zones. Therefore, it is important to understand the organic matter cycling in estuaries and coastal systems, especially characteristics and dynamics of river DOM and POM. But the DOM and POM is not homogeneous in terms of size or chemical characteristics so that we can't evaluate the linkage of terrestrial and coastal environments. The objective of this study is to understand the transport behavior of dissolved and particulate organic matter from terrestrial region to ocean. This study used carbon isotopic ratios (Δ^<14>C and δ^<13>C values) as tracers of organic carbon because the simultaneous use of these values adds a second dimension to isotopic studies of carbon cycling in surface aquatic environments.
Refractory organic materials, humic substances, were isolated from the river waters in Scotland, Ukraine, Japan and Indonesia by the XAD extraction. The Δ^<14>C values of dissolved humic substances ranged from -316‰ to +209‰, indicating spatial and temporal distribution.
To understand transport of POM in river systems, we selected three river systems (Tokachi, Ishikari and Kuji River systems) with different watershed conditions and carried out the observation at a fixed point in each river. The Δ^<14>C values range from -111 to -286‰ for the Tokachi River in northeast Hokkaido, -103〜-364‰ for the Ishikari River in southeast Hokkaido and -18.7〜-94.4‰ for the Kuji River in Kanto area in Japan. The paired Δ^<14>C vs. δ^<13>C distributions vary with rivers and seasons. These results suggest that the difference in paired Δ^<14>C vs. δ^<13>C distributions may reflect the water discharge and watershed environments.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), HOKKAIDO UNIVERSITY, 15310002

ヒマラヤチベット隆起とアジア-北西太平洋域気候・海洋変動の連動性-国際深海掘削計画、国際陸上掘削計画、IMAGESを活用した国際共同研究の推進-
科学研究費助成事業
2004 - 2004
多田 隆治, 鬼頭 昭雄, 酒井 治孝, 福澤 仁之, 横山 祐典, 山本 正伸
本企画研究では、
1)6月25日-27日に上海,同斉大学で開催された第2回IGCP-476国際シンポジウム・ワークショップと、引き続き6月28日-7月1日に行なわれた揚子江上流巡検・現地討論会に、IGCP-476国内委員会の主要メンバー10名を含む12名を参加させ、IODP,ICDP,IMAGESを活用したヒマラヤ・チベットの隆起と東アジア-北西太平洋域における気候・海洋変動の連動性に関する研究発表および研究計画の提案を行った。更に中国内陸部共同調査や東シナ海共同調査等の実現へ向けての打ち合わせを行なった。また、各国からの提案を基に、更に計画相互の連携や国際共同研究の可能性を探った。
2)IGCP-476が目指す科学目標を広く世間に知らせるために、地質学会第111回年会(於:千葉大)において、9月20日にシンポジウム「ヒマラヤ-チベットの隆起とアジアモンスーンの進化、変動」を開催し、4件の講演を行なった。その結果は、地質学雑誌特集号に発表される予定である。
3)本企画研究の年度前半の活動を通じて、気候モデルコミュニティーと古気候コミュニティー、テクトニクス研究コミュニティーの間の相互理解を更に深める事が重要であるとの認識に至った。そこで、各コミュニティー間の相互理解を進め、次のステップの戦略を考える目的で、12月23日-24日に、九州大学国際研究交流プラザにおいてIGCP-476国内ワークショップ「アジア・モンスーンの進化、変動理解のための統合的研究戦略」を開催し、22名の講演者、41名の参加者を集めた。そして、そこで、IGCP-476の基に結集した研究者コミュニティーの輪を、今後どの様に広げ、どの様な研究テーマに向かって、どの様な戦略で、研究活動を推進して行くべきかについて、議論を行なった。
日本学術振興会, 基盤研究(C), 東京大学, 16634012

High-resolution reconstruction of the paleoceanographic changes in the Japan Sea in response to the rapid changes in Asian monsoon
Grants-in-Aid for Scientific Research
2003 - 2004
TADA Ryuji, YAMAMOTO Masanobu, YOKOYAMA Yusuke, ITAKI Takuya
This research project aims to 1)reconstruct paleoceanographic changes of the Japan Sea during the last glacial period to Holocene with high time resolution wing multiple cores obtained from the Japan Sea, 2)compare these changes with changes in paleo-monsoon intensity that is estimated from proxies extracted from the same sediment cares, and 3)clarify how the surface and deepwater environment of the Japan Sea responded to the changes in the pattern and intensity of East Asian monsoon.
As indicators of the surface water environment, we used oxygen isotope ratio of planktonic foraminifers, alkenone paleatemperature, ^<14>C age of planktonic foraminifera, diatom assemblage, and organic carbon content to reconstruct temperature, salinity, origin, and biological productivity of the surface water. Whereas as indicators of the deepwater environment, degree of lamina preservation, C/S ratio, carbonate content, oxygen isotope ratio of benthic raminifers are used to reconstruct oxygenation, ventilation and corrosiveness of the deepwater. In addition, eolian dust grain size, flux, ESR signal intensity and crystallinity of quartz in the eolian dust component, and mineral composition are used to reconstruct westerly jet intensity, provenance of the eolian dust, and degree of dryness in the source areas.
Based on these reconstructions, we examined phase relationships among changes in the surface water environment, deepwater environment, and variabilities of Asian monsoon. The results basically support the hypothesis by Tada et al. (1999) that increased intensity of Asian summer monsoon enhanced discharge of Yangtze and other Chinese rivers, consequent expansion of lower salinity and higher nutrient East China Sea Coastal Water to the entrance of the Tsushima Strait, and increased the influx of the East China Sea Coastal Water into the Japan Sea. This in turn enhanced surface productivity and density stratification within the Japan Sea. The results also demonstrated detailed changes of sea surface temperature, surface productivity, and deepwater ventilation in the Japan Sea in response to the intrusion of the East China Coastal Water into the Japan Sea. The results further suggest the possible occurrence of millennial-scale changes in Asian monsoon and consequent changes in paleoceanographic conditions in the Japan Sea during Holocene.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (B), The University of Tokyo, 15310008

Chemical pproxy parametarization for evaluating prehistoric human activities.
Grants-in-Aid for Scientific Research
2001 - 2003
MINAGAWA Masao, IRINO Tomohisa, NAGAO Seiya, YAMAMOTO Masanobu, MATSUI Akira, NISHIMOTO Tohohiro
The purpose of this project is to prepare analytical procedures to identify a chemical evidence of human activities and to develop a chemical method to discriminate human remains from natural substances found in archeological sites. We focused organic compounds and stable isotope compositions, as both parameters are expected to characterize human agricultural activity and domestication of wild animals.
Soil samples were collected from some archaeological sites, modern agricultural fields and natural fields. Some compounds in lipid fraction were extracted for identifying molecular composition by gas chromatography-mass spectrometer analysis. Stable carbon and nitrogen isotopes ratios were simultaneously studied to characterize biogeochemical perturbation of soil organic matter under taking agricultural activity. Bone collagen isotope analyses were also applied to discriminate domestication of Sus scrofa from wild boar populations.
Soil organic matter analysis in modern agricultural field revealed that δ^<13>C and δ^<15>N of soil organic matter can be a useful proxy indicating C4 plants cultivation and consequent human perturbation of the soil microbe. Based on this result, soil samples from Bibi excavation site, a middle-Jomon sites in Chitose city, Hokkaido, evidences that there should be some kind treatment by prehistoric human at least 4,000 years, ago. In addition to this evidence molecular evidence by deoxycholic acids, a component of human bile, for soild lipid fraction also suggested likely usage of human leftover as fertilizer or toilet.
Same analysis was applied to soil samples from burial site, Kamifukushima Nakamachi in Gunma prefecture, a lost village by a volcanic eruption in Edo era. Deoxycholic acid was detected closely in the soil from both a farm and manure sink in a farmer house, indicating that such molecules can be a promising proxy indicating manure treatment.
Carbon and nitrogen isotope ratios of bone collagen were used to identify a individual of pigs from wild boar. We revealed that early domestication of boar could produce pigs having unusual isotopic patterns due to artificial feeding by human being, then it ca be useful proxy to detect early evidence of pig feeding.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), HOKKAIDO UNIVERSITY, 13308008

High-resolution reconstruction of environmental change off the east coast of Japan since the last 50,000 years reconded in a marine sediment core.
Grants-in-Aid for Scientific Research
2001 - 2003
OBA Tadamichi, YAMAMOTO Masanobu, NAGAO Seiya, OKADA Hisatake, NARITA Hisashi, IRINO Tomohisa
The northwest Pacific, where the cold Oyashio and the warm Kuroshio Currents meet each other today, is the most sensitive region in the North Pacific for monitoring the migration of the western boundary corrects in response to the past climatic change. A long core (45.82 m length) was recovered from 2,224 m water depths off the central Japan during the IMAGES cruise in 2001. A multi-disciplinary study was carried out on the core by analyzing the following research items : color, grain size, mineral composition, paleomagnetism, δ^<18>O, δ^<13>C Opal, CaCO_3, species of diatoms, coccolithophorids, radiolaria, planktonic foraminifera and benthic foraminifera, CaCO_3 preservation, Uk37', TOC, C/N, δ^<13>C_, δ^<15>N_, biomakers and pollen. The following main results ware obtained. The δ^<18>O curve of G.bulloides is similar to the standard oxygen isotope curve, suggesting continuous deposition over the last 145 ka. All warm water indices yielded by the four microfossil assemblages (diatoms, coccolith, radiolaria, planktonic foraminifera) show temperature decreases during the MIS 2 and 6, and increases during the MIS 5, although their correlation coefficients with each other are not always high (between 0.5 and 0,6). The Alkenon-derived temperature (19℃) at the core top agrees with the mean annual SST at present time in this region. The SST at the end of the MIS 2 was 13℃, which is seen today about 4.5 degree latitude north than the core site. Similar migrations in SST are inferred from the coiling ratio of N.pachyderma. The C/N ratio, δ^<13>C_ and δ^<15>N_ indicate that the TOC is mainly of marine origin, although terrestrial origin slightly increases during the MIS 6. The curve of the warm pollen index is similar to the δ^<18>O curve of G.bulloides, except for the MIS 6 and 5e when the land temperature changes inferred from the pollen curve precede the δ^<18>O curve.
Japan Society for the Promotion of Science, Grant-in-Aid for Scientific Research (A), Hokkaido University, 13304040

IGCP-581 第二回シンポジウム「アジアの河川システムの発達：テクトニクスと気候」　　　　　　　　　　　　　　　
会員提案型活動経費
山本正伸
日本地球掘削科学コンソーシアム, Principal investigator, Competitive research funding