チベット高原南東部における、最終氷期最寒冷期後の気候・環境変化に関する有機地球化学的研究(第18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17(2005)年度報告)

DOI 機関リポジトリ HANDLE オープンアクセス

書誌事項

タイトル別名
  • Organic Geochemical Study of Climatic and Environmental Changes around the Southeastern Part of the Tibetan Plateau since the Last Glacial Maximum(Proceedings of the 18^<th> Symposium on Chronological Studies at the Nagoya University Center for Chronological Research in 2005)

この論文をさがす

抄録

Little has been known about the details as to how the Tibetan Plateau had responded to global climatic oscillations in the paleoenvironmental history. Using a sediment core (ca. 4m in length) from Lake Pumayum Co located in the southeastern part of the plateau, we have been attempting to elucidate when the deglaciation and the warm and wet conditions since the last glacial maximum (LGM) took place around the region. For the purpose, we investigated the historical change of organic sources to the lake sediments with alkanes, an useful biomarker which can provide information on biological sources of sedimentary organic matter. The following results have been obtained so far : 1) The alkane source parameters (CPI&ACL) indicated that around 350cm in depth of the core, the relative contribution of organic matter from aquatic plants to sediments rapidly and strikingly decreased, while that of soil organic matter increased. 2) The ^<14>C ages obtained sometimes reversed between 240cm and 340cm, and further went back to younger ages between 340cm and 390cm. Based on the basis of a good correlation between the vertical profiles of ACL and the ages, it was suggested that the variable ages might be due to the changes of major sedimentary organic sources from aquatic plants to soil. 3) Although among the four ^<14>C ages obtained between 310cm and 340cm, one age reversed, all data showed the ages of almost 19,000 cal yr B.P. From this, it was implied that the rapid and striking change of the organic sources found around 350cm in core depth was caused by deglaciation.

収録刊行物

詳細情報

問題の指摘

ページトップへ