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古地理学报 ›› 2008, Vol. 10 ›› Issue (5): 495-509. doi: 10.7605/gdlxb.2008.05.008

• 岩相古地理学及沉积学 • 上一篇    下一篇

天津蓟县中元古界雾迷山组微指状叠层石及其对1250 Ma±叠层石衰减事件的响应

梅冥相  高金汉  孟庆芬  刘智荣   

  1. 中国地质大学（北京）地球科学学院，北京 100083
  • 出版日期:2008-10-01 发布日期:2008-10-01
  • 作者简介:梅冥相，男，1965年1月出生于贵州省仁怀市，现为中国地质大学（北京）教授，博士生导师，主要从事沉积学和地层学研究。 E-mail：meimingxiang@263.net。

Microdigital stromatolites and their response to the stromatolite decline at ca. 1250 Ma for the Mesoproterozoic WumishanFormation at Jixian section in Tianjin

Mei Mingxiang  Gao Jinhan  Meng Qingfen  Liuzhirong   

  1. School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083
  • Online:2008-10-01 Published:2008-10-01
  • About author:Mei Mingxiang, born in 1965, was graduated and obtained his Ph.D. degree from China University of Geosciences(Beijing) in 1993. Now he is a professor at School of Earth Sciences and Resources, China University of Geosciences (Beijing), and is engaged in sedimentology and stratigraphy.

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摘要：

天津蓟县中元古界雾迷山组是一套厚度超过3 000 m的叠层石碳酸盐岩沉积序列，在该序列中潮下相叠层石生物层、凝块石生物丘与潮坪相泥晶白云岩、泻湖相白云质泥页岩一起构成若干个环潮坪型米级旋回——“雾迷山旋回层”。在雾迷山组下部发育微指状叠层石，并被古生物学家定义为“Pseudogymnosolen mopanyuensis-Scuphus-Yangzhuang columnaris”组合，即假裸枝叠层石科叠层石，沉积学家将其解释为元古代文石（灰华）海底沉淀物所构成的叠层石，代表从太古代海底结壳状文石沉淀物叠层石到新元古代碎屑结构相、富泥碳酸盐叠层石过渡时期的特殊产物。因此，雾迷山组巨厚的叠层石碳酸盐岩沉积序列，记录了元古代文石灰华海底沉淀物所构成的特殊的叠层石大规模消亡的层位，为研究前寒武纪以叠层石为代表的微生物碳酸盐岩所经历的漫长而复杂的地质历史演变提供了宝贵的材料。

Abstract:

Abstract  The Mesoproterozoic Wumishan Formation at the Jixian section in Tianjin is a set of more than 3000 m-thick stromatolitic carbonate succession. In this seccession, several lithofacies units, i.e. the subtidal stromatolitic biostrome, the thrombolitic bioherm, tidal-flat micritic dolomite and lagoon facies dolomitic mudstone and shale, make up many meter- scale cycles of the peritidal carbonate type that are nominated as the Wumishan cyclothem. The microdigital stromatolites developed in the lower part of the Wumishan Formation, is defined as the “ Pseudogymnosolen mopanyuensis-Scuphus-Yangzhuang columnaris” assemblage by palaeontologists. This category of stromatolites has still been interpreted as the aroganite (tufa) sea floor precipitates by sedimentologists, and has further been thought as the special products during the transitional period from the stromatolites made up of the sea-floor aroganite precipites of the Archean to the stromatolites made up of the clastic and muddy carbonates of the Neoproterozoic. Therefore, an important horizon for the ending of the microdigital stromatolites was recorded in the Mesoproterozoic Wumishan Formation, which provides useful information for understanding the geologic and historical evolution of microbial carbonate rocks of the Precambrian which is characterized the stromatolites.