摘要
志留系兰多维列统埃隆阶石牛栏组顶部灰岩的沉积特征在黔北桐梓地区存在明显的差异:水坝塘羊石山剖面的泥裂显示海底曾经完全暴露于海面之上,而狮溪剖面石牛栏组与上覆韩家店组为整合接触,且石牛栏组顶部泥状灰岩中的鸟眼构造为典型的潮间带沉积,不完全暴露于海面。由此推测黔中古陆在桐梓上升时期的海岸线向北推移至水坝塘和狮溪之间约10km范围内。
Limestones of the Shihniulan Formation （late Aeronian, Silurian） consist of widespread shelly facies across northern Guizhou in the Upper Yangtze Platform, and are described here from the area in Tongzi County. The paleoenvironment of these beds in Tongzi generally maintained a near-shore setting and the sequence demonstrates a consistent paleogeographic pattern with open sea to the north. The formation exhibits an overall shallowing-up sequence （regression） caused by expansion of the Qianzhong Oldland during the Tongzi Uplift. The limestones near the top of the formation display diverse sedimentary characteristics which demonstrate northward migration of the shoreline. Mudcracks in the rocks at the Yangshishan Section, Shuibatang, indicate a subaerial setting in that location. However, birdseye struc- tures in the Shixi Section, 10 km north of Shuibatang, typically show an intertidal belt without complete e mergenee. Therefore, we interpret the shoreline of Qianzhong Oldland during the Tongzi Uplift may have shifted between Shuibatang and Shixi over a distance about 10 km. This work emphasizes the need for high-resolution logging of sequences to determine fine detail of facies changes in time and space.
出处
《地层学杂志》
CSCD
北大核心
2012年第4期718-722,共5页
Journal of Stratigraphy
基金
国家自然科学基金(No.41072002)
中国科学院创新工程方向性项目(KZCX2-YW-Q05-01)
国家基金委创新研究群体项目(41221001)资助
IGCP591项目"早
中古生代重大事件"的阶段成果
关键词
古地理
海岸线
黔中古陆
石牛栏组
埃隆期
志留纪
桐梓
贵州
shore line, Qianzhong Oldland, Shihniulan Formation, Aeronian, Silurian, Tongzi, Guizhou
