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柴达木盆地的新生界碎屑白云母40Ar/39Ar年龄及其地质意义

发表时间:2009-05-15  浏览量:1318  下载量:440
全部作者: 刘永江,RIESER A B,GENSER J,NEUBAUER F,袁四化,葛肖虹
作者单位: 吉林大学地球科学学院;萨尔茨堡大学地理地质系;成都地质矿产研究所
摘 要: 对柴达木盆地新生代沉积物的碎屑白云母40Ar/39Ar年龄测试获得4组年龄峰值:1) 350~450 Ma; 2) 220~280 Ma; 3) 122~140 Ma; 4) ~500 Ma. 其中第一组年龄在测试的样品中出现的频率最高。由此推断柴西地区的碎屑云母主要源区为阿尔金山和祁曼塔格—东昆仑山。早古生代的年龄(ca. 500 Ma)只在阿尔金山北侧红柳沟—拉配泉一带有少量报道,表明南部阿尔金山可能隆起的时间比北部地区晚或非常缓慢。这组年龄在祁连山中有报道,由于阿尔金断裂的长距离左行走滑,造成柴西地区的物源迁移,更多的相同年龄的地质体可能已经被错移到更西部。220~280 Ma的年龄仅在柴达木盆地北缘的沉积物中大量出现,在西部地区出现频率很小,推断其可能是阿尔金山地区二叠纪—三叠纪沉积盖层的再剥蚀产物,或者是来自最初可能就位于祁连山中的二叠纪—三叠纪的花岗质岩体。
关 键 词: 大地构造学;40Ar/39Ar年代学;柴达木盆地;阿尔金山;青藏高原;隆升剥露
Title: 40Ar/39Ar ages of detrital white mica constraining the Cenozoic development of the Qaidam Basin, China, and its geological implications
Author: LIU Yongjiang, RIESER A B,GENSER J,NEUBAUER F,YUAN Sihua,, GE Xiaohong
Organization: College of Earth Sciences, Jilin University;Department of Geography and Geology, University of Salzburg;Chengdu Institute of Geology and Mineral Resources
Abstract: 40Ar/39Ar dating of detrital white mica from Cenozoic sediments from the Qaidam Basin in western China yielded several age groups, including: 1) 350~450 Ma, 2) 220~280 Ma, 3) 122~140 Ma, and 4) ~500 Ma. The first group was the most common and dominant in the analyzed samples. It could be concluded that the main source regions of the detrital mica in the western Qaidam Basin were Altyn Mountains and Qimantagh-Kunlun Mountains. The Early Paleozoic ages (ca. 500 Ma) were documented so far only in the Hongliugou-Lapeiquan at the north side of the Altyn Tagh fault. This suggested late or slow continuous uplift of the southern Altyn Range. Because of long distance sinistral slip along the Altyn Tagh fault, the source area was transferred, and more geologic bodies of the same age were mis-shifted further westward. The age group of 220~280 Ma was documented only in the sediments of the northern basin margin other than the western area. This age group indicated re-denudated products of Permian–Triassic sedimentary cover of the Altyn Mountains or Permian–Triassic granite bodies that possibly originated in the Qilian Mountains.
Key words: tectonics; 40Ar/39Ar geochronology; Qaidam Basin; Altyn Mountain; Qinghai-Xizang Plateau; denudation
发表期数: 2009年5月第9期
引用格式: 刘永江,RIESER A B,GENSER J,等. 柴达木盆地的新生界碎屑白云母40Ar/39Ar年龄及其地质意义[J]. 中国科技论文在线精品论文,2009,2(9):936-942.
 
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