柴达木盆地新生代地层年代框架与沉积-构造演化  

Cenozoic stratigraphic chronology and sedimentary-tectonic evolution of the Qaidam Basin

作　　者：王伟涛 张培震 段磊 张博譞 刘康 黄荣 刘彩彩[3] 张竹琪[3] 郑德文[3,4] 郑文俊 张会平 Weitao;Wang;Peizhen Zhang;Lei Duan;Boxuan Zhang;Kang Liu;Rong Huang;Caicai Liu;Zhuqi Zhang;Dewen Zheng;Wenjun Zheng;Huiping Zhang(School of Earh Sciences and Engineering,Sun Ya-sen Universing Zhuhai 519082.China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519082.China;Slote Key Laboralory of Eanthqwake Dynamics,Iostitute of Geologo,China Earrhquake Administration,Beijing 100029,China;State Key Laboralory 0f Isorope Geochemistry,Guangzhou Irstiute of Geochenistry,Chinese Academy of Sciences,Giwangzhou 510040,China)

机构地区：[1]中山大学地球科学与工程学院,珠海519082 [2]南方海洋科学与工程广东省实验室(珠海),珠海519082 [3]中国地震局地质研究所,地震动力学国家重点实验室,北京100029 [4]中国科学院广州地球化学研究所,同位素地球化学国家重点实验室,广州510640

出　　处：《科学通报》2022年第28期3452-3475,共24页Chinese Science Bulletin

基　　金：国家自然科学基金(41888101,41872204,42030301);第二次青藏高原综合科学考察研究项目(2019QZKK0901);珠江创新团队项目(2016ZT06N331)资助

摘　　要：柴达木盆地的新生代地层非常发育,保存了从新生代早期至第四纪之间连续、完整的沉积记录.更为重要的是,柴达木盆地中发育丰富的新生代动、植物化石,为利用磁性地层学与古生物地层学方法建立盆地尺度的新生代地层年代框架,揭示盆地沉积演化、构造变形,以及青藏高原隆升、扩展的过程和动力学机制提供了重要的年代学制约.然而,目前关于柴达木盆地新生代地层层序和地层时代的认识还存在诸多矛盾之处。本文在野外观测、测量的基础上,总结、分析了柴达木盆地近年发表的相对连续、完整(厚度≥4500m)的磁性地层剖面,厘定了柴达木盆地新生代各岩石地层单元的地质年代.在此基础上,我们发现柴达木盆地西缘可能自始新世开始沉积,中部自渐新世(约31Ma)开始沉积,晚渐新世-早中新世沉积范围扩大至盆地东部柴达木盆地大部分地区自渐新世(31~26Ma)开始沉降,接受沉积的现象表明,青藏高原东北缘受印度板块与欧亚板块碰撞的影响开始发生构造变形.中中新世(约15Ma)以来,柴达木盆地沉积速率显著增加,盆地周缘山脉强烈隆升,揭示印度板块与欧亚板块持续汇聚作用导致的地壳缩短开始主宰高原东北部的构造变形,使柴达木盆地及其周缘造山带成为青藏高原向东北方向扩展过程中最新的组成部分.The Qaidam Basin hosts thick Cenozoic strata with an uninterrupted depositional time frame from early Cenozoic to the Quaternary, where remarkable number of mammalian fossils were discovered. These properties of the Cenozoic strata provide a unique chance to establish the basin-wide chronological framework by using palaeomagnetistratigraphy and biostratigraphy. Armed with the chronological framework, the sedimentary evolution and structural deformation of the Qaidam Basin and its adjacent region can be reconstructed to reveal the deformational processes and dynamic mechanism of the Tibetan Plateau expansion during the Cenozoic. According to the previous studies, the Cenozoic strata preserved in the Qaidam Basin, have been subdivided into seven primary progressively younger stratigraphic units: The Lulehe, Xia Ganchaigou, Shang Ganchaigou, Xia Youshashan, Shang Youshashan, Shizigou, and Qigequan formations. Despite the long study history of the Qaidam Basin, they are still controversial questions of basin-wide Cenozoic stratigraphic unit correlations and the time of formation of the Qaidam Basin. On the basis of the field observations, this paper summarizes relatively long magnetostratigraphic sections(thickness ≥ 4500 m), such as the Huatugou, Lulehe, Honggou, Dahonggou,and Huaitoutala magnetostratigraphies in the Qaidam Basin from the west to east. The magnetostratigraphies/refined magnetostratigraphies dated the Lulehe Fm. to span from 31 to 23.7 Ma, Xia Ganchaigou Fm. from 23.7 to 17 Ma, Shang Ganchaigou Fm. from ca. 17 to ca. 12 Ma, Xia Youshashan Fm. from ca. 12 to ca. 10 Ma, Shang Youshashan Fm. from ca.10 to ca. 7 Ma, and Shizigou Fm. is younger than ca. 7 Ma.Our interpretations suggest that the westernmost portion of the Qaidam Basin is probably formed in the Eocene, and the middle part of the basin began to accumulate sediments since the Oligocene(ca. 31–26 Ma). In the eastern part of the Qaidam Basin, Cenozoic subsidence was likely to initiate during the early to middle Miocene(ca. 16 Ma). Although

关 键 词：柴达木盆地 新生代地层 磁性地层学 沉积-构造演化 

分 类 号：P534.6[天文地球—古生物学与地层学] P542[天文地球—地质学]