湘西北王村地区寒武系花桥组是“钙屑浊积岩”吗?
DOI:
作者:
作者单位:

作者简介:

通讯作者:

中图分类号:

基金项目:

国家科技重大专项《大型油气田及煤层气开发》《全国油气基础地质研究与编图》课题(2011ZX05043-005)


"Calciturbidites" in Cambrian Huaqiao Formation, Wangcun, Northwestern Hunan: Is it real?
Author:
Affiliation:

Fund Project:

  • 摘要
  • |
  • 图/表
  • |
  • 访问统计
  • |
  • 参考文献
  • |
  • 相似文献
  • |
  • 引证文献
  • |
  • 资源附件
  • |
  • 文章评论
    摘要:

    扬子陆块东南缘的寒武系以各种类型的“碳酸盐重力流沉积物”发育为显著特征,前人据此认为存在一个连续的“台缘斜坡相带”。“古丈阶”国际层型剖面和点位(GSSP)——湘西北王村剖面的寒武系“花桥组”曾被认为由大量“钙屑浊积岩”组成。详细的沉积岩石学研究表明,王村剖面花桥组并非典型的“钙屑浊积岩”,而是以浪基面之下沉积的低能碳酸盐岩为主。其“浊积序列A段”中的所谓砾屑和底冲刷构造等,其实是由成岩期压切作用形成的大量灰岩透镜体和条带组成;“B段”中的所谓“波状层理”实际为压实变形的水平层理和类似风暴成因的丘-洼状交错层理,加之本次新发现的两层鲕粒灰岩,指示出受间歇性动荡水流影响的深水缓坡环境。结合区域沉积记录,对湘西北地区相应时期古地理格局提出新认识,认为存在未形成典型“台缘斜坡”的碳酸盐缓坡。

    Abstract:

    Cambrian sequences in Southeast margin of Yangtze Platform are represented by various types of \"carbonate gravity flow deposits\". Such cases have been viewed as the proxies of \"platform margin slope facies\". Sedimentary characteristics from the \"Huaqiao Formation\" at Wangcun section, Northwestern Hunan where is the \"GSSP\" of the \"Guzhangian Stage\" were considered to be \"Calciturbidites\" lithologically. The present study illustrates that they are not typical \"Calciturbidites\", but normal carbonate sediments from the low-energy depositional environments with depth below the wave base. Section A of the \"tipical turbidite sequence\",which were considered to develop in the Huaqiao Formation, is actually composed of numerous limestone lens and lumps formed in diagenesis compaction. Meanwhile, neither grading sequence grain stone nor burthen structures could be observed in the outcrop. \"Undulate bedding\" developed in section B of the \"turbidite sequence\" is actually deformed Horizontal bedding and hummocky cross bedding, which is probably storm-generated. The observations, combined with the discover of two beds of oolitic limestone from the lower member of the \"Huaqiao Formation\", indicate a deep-water environment that is intermittently effected by oscillatory currents. By comparison with sedimentary records in adjacent regions, the findings suggest a new understanding to palaeogeography in corresponding period: a carbonate shelf (ramp) without typical platform-edge slope developed in northwestern Hunan.

    参考文献
    相似文献
    引证文献
引用本文

周恳恳,牟传龙,梁薇,葛祥英.2012.湘西北王村地区寒武系花桥组是“钙屑浊积岩”吗?[J].地质学报,86(7):1143-1149.
ZHOU Kenken, MU Chuanlong, LIANG Wei, GE Xiangying.2012."Calciturbidites" in Cambrian Huaqiao Formation, Wangcun, Northwestern Hunan: Is it real?[J]. Acta Geologica Sinica,86(7):1143-1149.

复制
分享
文章指标
  • 点击次数:
  • 下载次数:
  • HTML阅读次数:
  • 引用次数:
历史
  • 收稿日期:2011-12-19
  • 最后修改日期:2012-02-23
  • 录用日期:2012-02-23
  • 在线发布日期: 2012-07-10
  • 出版日期: