中国地理科学(英文版) ›› 2002, Vol. 12 ›› Issue (3): 249-253.

• 论文 • 上一篇    下一篇

RELATIVE BRIGHTNESS INDEX AND IT'S CLIMATIC SIGNIFICANCE FROM LACUSTRINE SEDIM ENT OF NAPAHAI LAKE,NORTHWESTERN YUNNAN PLATEAU,CHINA

YIN Yong1, FANG Nian-qiao2, HU Chao-yong3, NIE Hao-gang2, QING Zun-li2   

  1. 1. The Key Laboratory of Coast & Island Development, Nanjing University, Nanjing 210093, P. R. China;
    2. China University of Geosciences, Beijing 100083, P. R. China;
    3. China University of Geosciences, Wuhan 430074, P. R. China
  • 收稿日期:2002-04-29 出版日期:2002-09-20 发布日期:2011-12-15
  • 作者简介:YIN Yong(1964- ),male,a native of Wuxi,Jiangsu Province, senior engineer, post-doctor research fellow of the Key Laboratory of Coast & Island Development, Nanjing University. His research interests include climate change and monsoon. E-mail: yinyong@nju.edu.cn.
  • 基金资助:

    Under the auspices of the National Natural Science Foundation of China(No.49672135)and National Key Project for Basic Research (No.G1998040800).

RELATIVE BRIGHTNESS INDEX AND IT'S CLIMATIC SIGNIFICANCE FROM LACUSTRINE SEDIM ENT OF NAPAHAI LAKE,NORTHWESTERN YUNNAN PLATEAU,CHINA

YIN Yong1, FANG Nian-qiao2, HU Chao-yong3, NIE Hao-gang2, QING Zun-li2   

  1. 1. The Key Laboratory of Coast & Island Development, Nanjing University, Nanjing 210093, P. R. China;
    2. China University of Geosciences, Beijing 100083, P. R. China;
    3. China University of Geosciences, Wuhan 430074, P. R. China
  • Received:2002-04-29 Online:2002-09-20 Published:2011-12-15

摘要:

Information on the palaeocnvironment from Late Pleistocene to Holocene in northwestern Yannan Plateau has been deduced from a study of a 28.81m-long core taken from Napahai Lake. The results from Relative Brightness Index (RBI) as well as those from the lithological analyses of bulk sediments, total organic carbon and granulometric analyses have been used to reconstruct the environmental and climatic evolution of the area. The ages were provided by three 14C datings. The record suggested a climate fluctuation between warm-dry and cool-wet from ca. 7 to 32ka B. P., which led a shallowing and swamping of the lake. The water level again increased quickly at ca. 32ka B. P., reached it's peak during LGM (Last Glacial Maximum, ca. 18-20ka B. P.) and remained relative high until ca. 1ka B. P. The high water level at LGM is attributed to cold-wet conditions. The area experienced an abrupt and unstable climatic changes during the transition period from 1 to 10ka B. P. with a dominated littoral environment. A warm-dry climate led to the contraction of the lake during the Holocene and reed-swamps became dominant. After a minor wet-cool pulse during the Late Holocene, the modem climate became to be established.

关键词: Relative Brightress Index, total organic carbon, particle size, palaeoclimate, Napahai Lake

Abstract:

Information on the palaeocnvironment from Late Pleistocene to Holocene in northwestern Yannan Plateau has been deduced from a study of a 28.81m-long core taken from Napahai Lake. The results from Relative Brightness Index (RBI) as well as those from the lithological analyses of bulk sediments, total organic carbon and granulometric analyses have been used to reconstruct the environmental and climatic evolution of the area. The ages were provided by three 14C datings. The record suggested a climate fluctuation between warm-dry and cool-wet from ca. 7 to 32ka B. P., which led a shallowing and swamping of the lake. The water level again increased quickly at ca. 32ka B. P., reached it's peak during LGM (Last Glacial Maximum, ca. 18-20ka B. P.) and remained relative high until ca. 1ka B. P. The high water level at LGM is attributed to cold-wet conditions. The area experienced an abrupt and unstable climatic changes during the transition period from 1 to 10ka B. P. with a dominated littoral environment. A warm-dry climate led to the contraction of the lake during the Holocene and reed-swamps became dominant. After a minor wet-cool pulse during the Late Holocene, the modem climate became to be established.

Key words: Relative Brightress Index, total organic carbon, particle size, palaeoclimate, Napahai Lake

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