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Biomarker records from core GH02-1030 off Tokachi in the northwestern Pacific over the last 23,000 years: Environmental changes during the last deglaciation
Title: | Biomarker records from core GH02-1030 off Tokachi in the northwestern Pacific over the last 23,000 years: Environmental changes during the last deglaciation |
Authors: | Inagaki, Masaki Browse this author | Yamamoto, Masanobu Browse this author →KAKEN DB | Igarashi, Yaeko Browse this author | Ikehara, Ken Browse this author |
Keywords: | North Pacific | Japan | East Asia | biomarker | glacial | deglacial | paleoenvironment | paleotemperature |
Issue Date: | Dec-2009 |
Publisher: | Springer |
Journal Title: | Journal of Oceanography |
Volume: | 65 |
Issue: | 6 |
Start Page: | 847 |
End Page: | 858 |
Publisher DOI: | 10.1007/s10872-009-0070-4 |
Abstract: | We investigated marine and terrestrial environmental changes at the northern Japan margin in the northwestern Pacific during the last 23,000 years by analyzing biomarkers (alkenones, long-chain n-alkanes, long-chain n-fatty acids, and lignin-derived materials) in Core GH02-1030. The UK'37-derived temperature in the last glacial maximum (LGM) centered at 21 ka was ~10˚C, which was 2˚C lower than the core-top temperature (~12˚C). This small temperature drop does not agree with pollen evidence of a large air temperature drop (more than 4˚C) in the Tokachi area. This disagreement might be attributed to a bias of UK'37-derived temperature within 2.5˚C by a seasonal shift in alkenone production. The UK'37-derived temperature was significantly low during the last deglaciation. Because this cooling was significant in the Kuroshio-Oyashio transition zone, the temperature drops are attributable to the southward displacement of the Kuroshio-Oyashio boundary. Abundant lignin-derived materials, long-chain n-alkanes and long-chain n-fatty acids indicate a higher contribution of terrigenous organic matter from 17 to 12 ka. This phenomenon might have resulted from an enhanced coastal erosion of terrestrial soils due to marine transgression and/or an efficient inflow of higher plant debris to river waters from 17 to 12 ka. |
Type: | article (author version) |
URI: | http://hdl.handle.net/2115/51231 |
Appears in Collections: | 環境科学院・地球環境科学研究院 (Graduate School of Environmental Science / Faculty of Environmental Earth Science) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 山本 正伸
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