Marine and terrestrial climate changes at the northern Japan margin in the northwestern Pacific during the last 23,000 years

HR: 0800h
AN: PP11B-0515 [Abstracts]
TI: Marine and terrestrial climate changes at the northern Japan margin in the northwestern Pacific during the last 23,000 years
AU: Inagaki, M
EM: myama@ees.hokudai.ac.jp
AF: Faculty of Environmental Earth Science, Hokkaido University, Kita-10, Nishi-5, Kita-ku, Sapporo, 060-0810, Japan
AU: * Yamamoto, M
EM: myama@ees.hokudai.ac.jp
AF: Faculty of Environmental Earth Science, Hokkaido University, Kita-10, Nishi-5, Kita-ku, Sapporo, 060-0810, Japan
AU: Igarashi, Y
EM: VZQ06055@nifty.com
AF: Institute for Paleoenvironment of NOrthern Regions, Koyocho 3-7-5, Kitahiroshima, 061- 1134, Japan
AU: Ikehara, K
EM: k-ikehara@aist.go.jp
AF: Geological Survey of Japan, AIST, Higashi 1-1-1, Tsukuba, 305-8567, Japan
AB: We investigated marine and terrestrial environmental changes at the northern Japan margin in the northwestern Pacific by analyzing biomarkers in Core GH02-1030 to clarify the climate linkage between the ocean and land. The UK"37-derived temperature record was characterized by cooling events at ~19.6 ka, ~15.8 ka (Oldest Dryas), ~12.1 ka (Younger Dryas) and ~10.1 ka, and the temperature drops were attributable to the southward displacement of the subarctic boundary, which presumably resulted from both the depressed North Pacific High and the enhanced Okhotsk High. Short-chain C14-C18 n-fatty acids, derived mainly from marine organisms, showed higher concentrations during the last deglaciation, reflecting an enhanced marine production caused by the stronger Aleutian Low. Abundance ratio of long-chain n-alkanes and long-chain n-fatty acids to lignin, which are indices of herb contribution, showed maxima at ~16 ka and ~11.5 ka, indicating the expansion of grassland in a cold and dry climate. Abundant lignin indicated a higher contribution of terrigenous organic matter during the last deglaciation, reflecting an enhanced coastal erosion of terrestrial soils due to sea level rise and/or an efficient inflow of higher plant debris to river waters during this period.
DE: 1055 Organic and biogenic geochemistry
DE: 4954 Sea surface temperature
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting