Sedimentary record of Late Neoproterozoic rifting in the NW Tarim Basin, China
Sedimentary record of Late Neoproterozoic rifting in the NW Tarim Basin, China
复制标题
DOI：
10.1016/j.precamres.2010.05.015
复制
发表时间：
2010-08
影响因子：
3.8
通讯作者：
S. Turner
中科院分区：
文献类型：
--
作者：
S. Turner
塔里木盆地西北部新元古代晚期的沉积物，包括一个600- 900米厚的非海相-海相同裂谷序列，揭示了早期的伸展作用。本研究提供了阿克苏和乌什附近两个实测和解释地层剖面的新资料。同裂谷序列不整合地覆盖在高级变质基底之上，由非海相的苏盖特布拉克组和海相的却格布拉克组组成。苏盖特布拉克组的特征是基底（冲积扇）砾岩向上进入河流和湖泊相砂岩和粉砂岩。基底不整合的地层位置和基底砾岩的厚度是局部可变的，这反映了在伸展开始期间，除了预先存在的地形之外，还形成了小的、孤立的沉积中心。苏盖特布拉克组还含有一系列整合的喷出玄武岩，它们记录了幕式火山作用，并与河流相和湖泊相一起指示了裂谷系统的发育和伸展断裂的生长、相互作用和联系。整合型的其格布拉克组以前滨-潮间相碳酸盐岩为特征，其中含有丰富的叠层石，代表了一次全盆海侵和裂谷顶极阶段。这个同生裂谷序列与澳大利亚西北部的类似序列相关，并对应于在新元古代至早古生代的最新时期，塔里木地块与东冈瓦纳大陆至少部分分离。
Upper Neoproterozoic sediments which have been exhumed in the NW Tarim Basin, China, comprise a 600–900m thick non-marine to marine synrift succession that reveals an early phase of extension. This study presents new data from two measured and interpreted stratigraphic sections near Aksu and Wushi. The synrift succession unconformably overlies high-grade metamorphic basement and consists of the non-marine Sugaitebulake Fm and the marine Qegebulake Fm. The Sugaitebulake Fm is characterised by a basal (alluvial fan) conglomerate that passes upwards into fluvial and lacustrine facies sandstones and siltstones. The stratigraphic position of the basal unconformity and the thickness of the basal conglomerate is locally variable, which reflects the formation of small, isolated depocentres during the onset of extension, in addition to a pre-existing topography. The Sugaitebulake Fm also contains a series of concordant, extrusive basalts which record episodic volcanism, and together with the fluvial and lacustrine facies indicate the development of the rift system and the growth, interaction and linkage of extensional faults. The conformable Qegebulake Fm is characterised by foreshore to intertidal facies dolomites that contain abundant stromatolites, representing a basin-wide marine transgression and the rift climax stage. This synrift sequence is shown to correlate with a similar succession in NW Australia, and corresponds to at least partial separation of the Tarim Block from East Gondwana during the latest Neoproterozoic to Early Palaeozoic.