TY - JOUR
T1 - Changes of organic matter sources in sediment cores from a high-altitude lake (Pumoyum Co, southeastern Tibetan plateau) over the last 19,000 years
AU - Watanabe, Takahiro
AU - Matsunaka, Tetsuya
AU - Nakamura, Toshio
AU - Nishimura, Mitsugu
AU - Nara, Fumiko Watanabe
AU - Kakegawa, Takeshi
AU - Zhu, Liping
N1 - Funding Information:
The authors express their gratitude to the staff of the CCR, Nagoya University, for the 14 C dating. We thank the members of the China–Japan Scientific Research Expedition to Lake Pumoyum Co, for their help during the acquisition of the sediment cores. We also acknowledge the students and staff of Tohoku University for the sample preparation and δ 13 C measurements. We thank Dr. Yu. Vasil’chuk and anonymous reviewer for helpful comments. This research was partly supported by a Grant-in-Aid for JSPS Fellows to T.W. (No. 20-4967).
PY - 2010/4
Y1 - 2010/4
N2 - Lake Pumoyum Co is on the southeastern Tibetan plateau (altitude, ∼5030 m asl; lake surface area, 281 km2; maximum water depth, 65 m). We obtained 14C dates on total organic carbon (TOC) for three sediment cores from Lake Pumoyum Co, covering the period from the last glacial to the Holocene, and compared them with 14C ages on plant residue concentrates (PRC fraction, mainly terrestrial plant residues) and aquatic plant fragments in the cores. The calibrated ages of TOC were older than those of the PRC fraction in the sediment cores by ca. 0.6-11.3 kyr. The calculated dead carbon fraction (fdead carbon) values for TOC increased during 9.5-5.5 cal ka BP, and fluctuations of fdead carbon paralleled variations in Asian monsoon intensity [Y. Wang et al., Nature 451 (2008) 1090]. One possible explanation for these results is that large amounts of terrestrial organic materials containing old carbon were supplied to the lake ("old carbon effects" from lake terrace, paleosol and/or stratum with dead 14C) when the lake level rose rapidly and its catchment area expanded during the Holocene climate optimum (9.5-5.5 cal ka BP).
AB - Lake Pumoyum Co is on the southeastern Tibetan plateau (altitude, ∼5030 m asl; lake surface area, 281 km2; maximum water depth, 65 m). We obtained 14C dates on total organic carbon (TOC) for three sediment cores from Lake Pumoyum Co, covering the period from the last glacial to the Holocene, and compared them with 14C ages on plant residue concentrates (PRC fraction, mainly terrestrial plant residues) and aquatic plant fragments in the cores. The calibrated ages of TOC were older than those of the PRC fraction in the sediment cores by ca. 0.6-11.3 kyr. The calculated dead carbon fraction (fdead carbon) values for TOC increased during 9.5-5.5 cal ka BP, and fluctuations of fdead carbon paralleled variations in Asian monsoon intensity [Y. Wang et al., Nature 451 (2008) 1090]. One possible explanation for these results is that large amounts of terrestrial organic materials containing old carbon were supplied to the lake ("old carbon effects" from lake terrace, paleosol and/or stratum with dead 14C) when the lake level rose rapidly and its catchment area expanded during the Holocene climate optimum (9.5-5.5 cal ka BP).
KW - AMS
KW - Carbon cycles
KW - Climate change
KW - Environmental change
KW - Lake Pumoyum Co
KW - Lake sediment
KW - Organic matter sources
KW - Radiocarbon dating
KW - Tibetan plateau
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U2 - 10.1016/j.nimb.2009.10.100
DO - 10.1016/j.nimb.2009.10.100
M3 - Article
AN - SCOPUS:77949902623
VL - 268
SP - 1070
EP - 1072
JO - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
JF - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
SN - 0168-583X
IS - 7-8
ER -