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阿尔金断裂带年代学和阿尔金山隆升
  • ISSN号:0563-5020
  • 期刊名称:《地质科学》
  • 时间:0
  • 分类:P542[天文地球—构造地质学;天文地球—地质学] P597[天文地球—地球化学;天文地球—地质学]
  • 作者机构:[1]吉林大学地球科学学院,长春130061, [2]Institute of Geology and Paleontology, Salzburg University,Salzburg A-5020, Austria, [3]东方地球物理公司敦煌分院,甘肃敦煌736200
  • 相关基金:国家自然科学基金项目(批准号:40572135)和博士点基金项目(编号:20040183055)资助.
中文摘要:

对阿尔金山断裂带内变形的中生代剪切带中眼球状片麻岩、糜棱岩化花岗片麻岩和新生代剪切带中强变形绿片岩系列样品中同构造新生云母矿物的^40Ar-^39Ar法定年,获得了164.3—178.4Ma和26.3—36.4Ma两组年龄。结合阿尔金走滑断裂水平错距的研究,认为164.3—178.4Ma的年龄代表阿尔金走滑断裂带的起始活动时间(早侏罗世末—中侏罗世),尔后分别在距今100—85Ma,40—25Ma和10—8Ma发生多次脉冲式走滑活动。新生代沉积物研究表明上干柴沟组和下干柴沟组砂岩骨架矿物成份含量明显不同,随时间变化,石英含量减少,岩屑组份和不稳定矿物含量增加,分选性逐渐变差。这表明阿尔金山在渐新世(下干柴沟组时期)开始发生明显的隆升。地震和柴达木—塔里木盆地沉积速率资料显示在晚中新世山体也发生了一次强烈的隆升。七个泉组(上新世末—早更新世初)和下伏沉积物(上新世中期)之间的角度不整合反映了最后一次强烈隆升事件发生在晚上新世。多数隆升事件和阿尔金断裂带新生代脉冲式活动的同位素年龄完全一致,表明阿尔金山的隆升和断裂带的活动具有密切的成因联系。

英文摘要:

The ^40Ar-^39Ar dating of the syntectonic growing micas, separated from the deformed augen gneiss and mylonitized granitic gneiss in the Mesozoic shear zone and strongly mylonitized greenschist in the Cenozoic shear zone from the transect across the Altun fault zone, yielded two age groups of 164.3 - 178.4 Ma and 26.3 - 36.4 Ma. Combining with the offset studies of the strike-slipping of Altun fault, it suggested that the ages of 164. 3 - 178.4 Ma should represent the initial activity age (the latest Early Jurassic-Middle Jurassic) of the Ahun strike-slip fault. After that, the strike-slipping activities along the fault occurred 85 - 100 Ma, 25 - 40 Ma and 8 - 10 Ma ago, respectively. The studies on the Cenozoic sediments showed the different contents of the sandstone framework components between the Xiaganchaigou (E3 g) and Shangganchaigou (N1 g )Formations in the western Qaidam Basin. With the sedimentary process, the quartz component decreased, the elastic component increased with more unstable minerals and worse sorting degree, which suggested that the Ahun Mountains began to rise in Oligocene (sedimentary period of the Xiaganchaigou Formation). A strong uplifting happened in Late Miocene according to the evidence from the seismic section of the western Qaidam Basin and sedimentary velocity of the Qaidam and Tarim Basins. The last and strongest rising event occurred in the end of Early Pleistocene according to the unconformity between the Qigequan Formation (from the end of Pliocene to the 1 eginning of Early Pleistocene) and the overlying sediments (Middle Pleistocene). Most of uplifting events were consistent with the isotopic ages recorded in the fault belt, indicating that the mountain uplifting should be related to the activities of strike slipping of the Ahun fault zone.

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期刊信息
  • 《地质科学》
  • 北大核心期刊(2011版)
  • 主管单位:中国科学院
  • 主办单位:中国科学院地质与地球物理研究所
  • 主编:肖文交
  • 地址:北京9825信箱
  • 邮编:100029
  • 邮箱:dzkx@mail.igcas.ac.cn
  • 电话:010-82998115 82998109
  • 国际标准刊号:ISSN:0563-5020
  • 国内统一刊号:ISSN:11-1937/P
  • 邮发代号:2-392
  • 获奖情况:
  • 中国期刊方阵“双百期刊”,除SCI外被国外的主要期刊检索机构检索
  • 国内外数据库收录:
  • 美国化学文摘(网络版),荷兰地学数据库,荷兰文摘与引文数据库,美国剑桥科学文摘,英国动物学记录,中国中国科技核心期刊,中国北大核心期刊(2004版),中国北大核心期刊(2008版),中国北大核心期刊(2011版),中国北大核心期刊(2014版),中国北大核心期刊(2000版)
  • 被引量:14126