末次冰消期以来古猪野泽湖相地层沉积学及湖面波动历史

本文选取古猪野泽地区的青土湖剖面、西渠剖面、沙坑井剖面、九坨墚剖面作为研究对象,通过广泛野外地貌考察、剖面地层对比,作者认为古猪野泽最高湖面的海拔高度为1313~1315m,气候变化自末次冰期以来共经历了2个成湖期(13000~9500 yr BP、6700~1100 yr BP)。9500~6700 yr BP期间,本区域基本都沉积了风成砂,湖泊岸堤的14C测年均未发现早全新世高湖面的证据。通过地球物理化学指标分析及可靠14C测年,重建了区域末次冰消期以来的气候干湿变化历史:15800~13000 yr BP,为冷干的气候环境;13000~9500 yrBP,为凉湿的气候环境;9500~6700 yr BP,为暖干的气候环境;6700~4300 yr BP,为暖湿的气候环境,其中6700~5650 yr BP为气候最适宜期;4300~2700 yr BP,为干旱/湿润的过渡时期;2700~0 yr BP,为干旱的气候环境。

Lacustrine Strata Sedimentology and Lake- level History in Ancient Zhuyeze Lake Since the Last Deglaciation

The ancient Zhuyeze Lake lies in east Hexi corridor of the Northwest China.The research on paleoclimate of the lake-ancient Zhuyeze lake will help to understand the processes and mechanism of climate change in northwest China since the Last Deglaciation.Related researches of this area were done from 1960s,and researches on environment changes have become the "hotspots" during the last 10 years.This research focused on four sections(Qingtuhu section,Xiqu section,Sakengjing section,Jiutuoliang section) in ancient Zhuyeze Lake.Much work was done in spot investigation,section strata contrast,geophysical analyses,geochemical analyses and dependable14C dating in order to retrieve the dry-wet history of climate changes in ancient Zhuyeze Lake since the Last Deglaciation.The main conclusions were as follows: 1.The highest terminal lake level was 1313～1315m.In Holocene,the highest lake level was 1308～1309m occurring between 6700～5800 yr BP.2.After geophysical and geochemical analyses,high-resolution records of the climate change since the Last Deglaciation were revealed as follows: cold and dry during 15800-13000 yr BP,cool and wet during 13000-9500 yr BP,cold and dry during 9500-6700 yr BP,warm and wet during 9500-7200 yr BP,warm and dry during 4300-2700 yr BP,and at last dry during 2700-0 yr BP.