LATE MIDDLE PLEISTOCENE SEDIMENTARY SEQUENCES AND TIME EVIDENCE IN HONGSHUICHUAN REGION, EAST KUNLUN MOUNTAINS
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摘要: 中更新世晚期, 东昆仑布青山已开始大幅度崛起.布青山北坡查干额日格地区第四系厚达百余m, 整体上为具多元结构的洪冲积扇复合建造体, 其中较细粒沉积层中产丰富的孢粉化石.根据冲洪积层中植物孢粉组合分析, 确定其时代为中更新世, 孢粉组合所反映的当时植被类型为混交林-荒漠草原.冲洪积层中部的热释光年龄为(30 2± 2 2) ka, 古地磁测量确定出琵琶反向极性1和琵琶反向极性2两个亚时, 时代为中更新世晚期.Abstract: Buqingshan Mountains have already begun to rise abruptly on a large scale in the late Middle Pleistocene. The Quaternary deposit is more than 100 m thick in Chaganerige, northern slope of the Buqingshan Mountains, Kunlun Mountain Ranges. This deposit layer is defined as the multivariant complex formation of pluvial-alluvial fans, in the relatively fine sedimentary layers of which occur abundant sporomorphs. The analysis of plant sporopollen assemblage in the alluvial and pluvial formations is used to determine that the Quaternary pluvial-alluvial deposit occurred in the Middle Pleistocene. In addition, the plant type at that time reflected by the sporopollen assemblage is determined to be a mixedforestdesert steppe. The thermoluminescent dating of the pluvial-alluvial deposit is (302±22)?ka. The paleomagnetic measurement is used to identify two subtimes: Biwa reverse polarization No.1 and Biwa reverse polarization No.2, and also to identify the late Middle Pleistocene.
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图 1 研究区地质简图及交通位置
Fig. 1. Sketch map showing geology and traffic position in study area
图 2 青海省都兰县红水川查干额日格中更新统柱状剖面
Fig. 2. Columnar section of Middle Pleistocene in Chaganerige area of Hongshuichuan, Dulan County, Qinghai Province
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