地学前缘 ›› 2014, Vol. 21 ›› Issue (6): 346-355.DOI: 10.13745/j.esf.2014.06.033

• 论文 • 上一篇    下一篇

塔里木盆地苏盖特布拉克地区下寒武统风暴岩及其地质意义

宋金民，罗平，刘树根，杨迪，王鑫，李朋威   

  1. 1. 油气藏地质及开发工程国家重点实验室, 成都理工大学, 四川 成都 610059 2. 中国石油勘探开发研究院, 北京 100083 3. 中国石油 华北油田公司 地球物理勘探研究院, 河北 任丘 062552 4. 中国石油化工股份有限公司 石油勘探开发研究院, 北京 100083
  • 收稿日期:2013-05-13 修回日期:2013-09-10 出版日期:2014-11-15 发布日期:2014-11-15
  • 作者简介:宋金民（1983—），男，博士，讲师，主要从事碳酸盐岩沉积储层研究和教学工作。E-mail:songjinmin@sohu.com
  • 基金资助:

    国家自然科学基金青年科学基金项目（41302086）；国家重点基础研究发展计划“973”项目（2012CB214805）

Lower Cambrian tempestites and their geological significances in Sugaitblak area, Tarim Basin

  • Received:2013-05-13 Revised:2013-09-10 Online:2014-11-15 Published:2014-11-15

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摘要：

塔里木盆地苏盖特布拉克地区下寒武统肖尔布拉克组发育较为典型的风暴岩。风暴沉积标志主要有冲刷充填构造、风暴砾屑层和丘状交错层理等。在野外实测和室内薄片观察基础上，依据风暴沉积物、沉积位置和沉积标志组合的不同，划分出5种风暴沉积序列。序列Ⅰ为mm级或cm级的递变纹层，截切深水微生物礁，为风暴浪基面以下的深水陆棚远源风暴浊流沉积；序列Ⅱ发育异地型风暴砾屑、粒序段、平行纹层段和水平层理黑色钙质页岩，为风暴浪基面与晴天浪基面之间的缓斜坡下部沉积；序列Ⅲ为风暴成因的生屑、砾屑与平行纹层、丘状纹层的组合，多出现在风暴浪基面与晴天浪基面之间的缓斜坡上部；序列Ⅳ以渠模与复合丘状交错层理的组合为特征，为水体较浅的晴天浪基面附近的沉积；序列Ⅴ由风暴砂砾屑及沉积充填构造、平行纹层段组成，上部单元为正常天气沉积的蓝细菌礁滩垮塌体，为晴天浪基面以上的台地边缘礁滩前缘沉积。风暴层序自下而上的沉积环境演化为深水陆棚→浅水陆棚缓斜坡下部→缓斜坡上部→台地边缘前缘，形成向上变浅沉积特征。风暴岩的发现和研究，对于塔里木早寒武世古纬度与古板块演化、古地理及沉积学研究具有重要意义。

 

关键词: 苏盖特布拉克地区, 肖尔布拉克组, 风暴岩, 沉积模式, 地质意义

Abstract:

Lower Cambrian tempestites are found in Xiaoerbulak Formation in Sugaitblak area, Tarim Basin. The major storm sedimentary markers are scouring filling structures, storm flowgenerated gravelstones and hummocky cross stratifications (HCS). Based on outcrop observation in the field and thin section, a total of five types of storm deposits are recognized according to the synthesis of storm sediments, sedimentary position and depositional markers. Type Ⅰ is represented by the graded lamination in millimeter or centimeter scale downcutting the underlying microbial reef. They are formed by distal storm turbidity currents below stormwave base. Type Ⅱ is composed of allodapic storm gravelstone (of member A), graded member (B), parallel lamination member (C) and black calcareous shale with horizontal bedding (E2), which are deposited at the lower part of gentle slope between the storm and the fine weather wave bases. Type Ⅲ consists of storm bioclast, gravelstone, parallel lamination and HCS, depositing at the upper part of the slope. Type Ⅳ is characterized by gutter casts and composite HCS, which are formed in the vicinity of the fair weather wave base. Type Ⅴ develops storm intraclastic limestones and scouring filling structures (A) and parallel lamination (C), overlying cyanobacteria reefbank collapsing deposition in fair weather. They are formed in the front of platform margin above fair weather wavebase. The depositional evolution of tempestites is: the deep water shelf→the lower part of gentle slope→the upper part of gentle slope→the front of platform margin, which are characteristic of shallowing upward. The discovery and researches of tempesites in the studied area are of great significances for understanding the palaeolatitude and palaeoplate evolution as well as the palaeogeographic environments and sedimentary evolution in the Early Cambrian of Tarim plate.

 

Key words:  Sugaitblak area, Xiaoerblak Formation, tempestites, depositional model, geological significance

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