The discovery of annually laminated sediments (varves) from shallow Sugan Lake in inland arid China and their paleoclimatic significance  

作　　者：ZHOU AiFeng CHEN FaHu QIANG MingRui YANG MeiLin ZHANG JiaWu 

机构地区：[1]CAEP,Key Laboratory of West China’s Environmental System(Ministry of Education),Lanzhou University,Lanzhou 730000,China

出　　处：《Science China Earth Sciences》2007年第8期1218-1224,共7页中国科学（地球科学英文版）

基　　金：the NSFC (National Natural Science Foundation of China);National Innovation Research Team Project (Grant No. 40421101);the NSFC Research Projects (Grant Nos. 40301050 and 40301051)

摘　　要：Detailed examination of sedimentary cores retrieved from Sugan Lake in the northern Qaidam Basin of northwest China’s Tibetan Plateau reveal that fine laminated beddings form in the sediments where water depth exceeds 3 m. Seasonal surface sediments trapped at the bottom of the lake suggest that sediments deposited during summer and autumn are mainly light colored monohydrocalcites, while those deposited in winter are dark organic matter, indicating that varve layers form under modern limnological conditions. Continuous varve sediments comprising four types have accumulated in the upper 5.5 m of Core SG03I from the center of the lake. All types exhibit clear seasonality indicative of annual deposition. Varve counts correspondence with 210Pb dates on recent sediments in the upper core suggest the continuous varves of the upper 5.5 m of the core formed in the late Holocene (2670 a BP). The Sugan Lake varve sequence is the first demonstration of annually laminated sediments re-ported in arid western China.Detailed examination of sedimentary cores retrieved from Sugan Lake in the northern Qaidam Basin of northwest China’s Tibetan Plateau reveal that fine laminated beddings form in the sediments where water depth exceeds 3 m. Seasonal surface sediments trapped at the bottom of the lake suggest that sediments deposited during summer and autumn are mainly light colored monohydrocalcites, while those deposited in winter are dark organic matter, indicating that varve layers form under modern limnological conditions. Continuous varve sediments comprising four types have accumulated in the upper 5.5 m of Core SG03I from the center of the lake. All types exhibit clear seasonality indicative of annual deposition. Varve counts correspondence with 210Pb dates on recent sediments in the upper core suggest the continuous varves of the upper 5.5 m of the core formed in the late Holocene (2670 a BP). The Sugan Lake varve sequence is the first demonstration of annually laminated sediments reported in arid western China.

关 键 词：Sugan LAKE VARVE TIBETAN Plateau ARID China 

分 类 号：P532[天文地球—古生物学与地层学]