@article{oai:nagoya.repo.nii.ac.jp:00011836,
 author = {松中, 哲也 and Matsunaka, Tetsuya and 西村, 弥亜 and Nishimura, Mitsugu and 中村, 俊夫 and Nakamura, Toshio and 渡邊, 隆広 and Watanabe, Takahiro and 寺井, 久慈 and Terai, Hisayoshi and 中野, 志穂 and Nakano, Shiho and Zhu, Liping},
 journal = {名古屋大学加速器質量分析計業績報告書},
 month = {Mar},
 note = {Little has been known in details as to how the Tibetan Plateau had responded to global climatic oscillations in the paleoenvironmental history. In order to elucidate when and how the deglaciation and the subsequent warm and wet climate after the last glacial maximum (LGM) started on the plateau, and then were linked to the restoration of the southwest monsoon, we have been trying to organic-geochemically analyze the paleoenvironments recorded in a 4m-long sediment core (PY409PC) collected from Lake Pumayum Co in a southeast part of the plateau. However, it was found that the sediment ages strikingly reversed from 14,220yrB.P to 19,507yrB.P between the bottom and 40cm in depth toward the top, and the age reversal is hindering us from going on the paleoenvironmental analysis. It appeared that the reversal was caused by the contribution of "old carbon" from certain natural source to the lake, rather than a contamination during sampling and analyzing. We attempted to make clear the old carbon source and the factors controlling the contribution, and obtained the following results: 1) As the supply of organic matter to the lake decreased since ca.14,200yrB.P, the type of organic matter deposited probably changed from soil organic matter originated mainly from a kind of grasses grown on relatively wet lands to those from recent terrestrial plants on ordinary lands with age. This is seemed to have been caused by the environmental change that the wet lands surrounding the lake at that time were lost by a rapid expansion of the water basin, due to the activation of water circulation. 2) It is likely that organic matter with "old carbon" has continuously contributed to the lake sediments as a background at least since ca.14,200yrB.P. The results suggested that the age reversal found in our core sample was resulted from the increasing relative contribution of soil organic matter with "old carbon" to the sedimentary organic matter, coupled with the decrease in a supply of new organic matter from land with age., 第19回名古屋大学年代測定総合研究センターシンポジウム平成18(2006)年度報告<第2部> Proceedings of the 19th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research in 2006 日時:平成19 (2007)年1月15日(月)～17日(水) 会場:名古屋大学シンポジオン Date:January15th-17th, 2007 Venue:Nagoya Uhiversity Symposion Hall},
 pages = {162--171},
 title = {チベット・プマユムツォ湖の柱状堆積物に見られる年代逆転に関する一考察(第19回名古屋大学年代測定総合研究センターシンポジウム平成18(2006)年度報告,第2部)},
 volume = {18},
 year = {2007}
}