The Lowest Member of Lower Triassic Feixianguan Formation in Upper Yangtze Region: Sedimentary Records from Sluggish Water to Turbulent Ocean after the Mass Extinction
详细信息
- 责任者：Shi Zhiqiang (Institute of Sedimentary Geology ; Chengdu University of Technology ; Chengdu ; 610059 ; China) ; Yi Haisheng
- 刊名：Geological Review
- 出版年：2010
- 卷期：56(6)
- 关键词：飞仙关组 ; Feixianguan Formation ; 绝灭 ; extinction ; 海洋环境 ; marine environment ; 扬子地台 ; Yangtze Platform
- 页码：p.769-780
- 图表：5 illus., 60 refs.
- 分类号：1200
- issnNo：ISSN0371-5736
- isbnNo：CN11-1952/P
摘要
In upper Yangtze Region, laminated microcrystalline limestone, calcareous shale or ribbon limestone widely developed during the earliest stage of Early Triassic, just after the Permian-Triassic boundary (PTB) mass extinction, which represented the Sluggish oceanic circulation. As seen at the sections in Jiangyou, Guangyuan, Wangcang County, Sichuan Province and Chongqing Municipality, the storm-related sediments such as brecciform limestone, flat-pebble conglomerate calcirudyte, hummocky cross-bedding grain limestone, ripple bedding siltstone uplapped on the laminated or ribbon deposits. Erosion surfaces were usually seen between the low-energy deposits and the storm-related turbulent oceanic deposits, which indicated the unusual paleo-oceanographical and paleoclimate changes during the earliest stage of Early Triassic interval. As a main type of Early Triassic anachronistic facies which showed the turbulent oceanic conditions, brecciform limestone and flat-pebble conglomerate calcirudyte were widely seen in the northwestern part of upper Yangtze Region.