下扬子盆地早、中三叠世古地理及其演化

<正> 下扬子盆地在早、中三叠世,古地理位置处于华北古陆与江南海隆之间,为一温暖清洁的陆表海,沉积了以碳酸盐岩为主的海相沉积物。主要岩石类型包括灰泥灰岩、粒泥灰岩、颗粒灰岩、准同生白云岩以及泥、页岩等。 据殷鸿福(1986)资料,华北地台及扬子地台在晚二叠世的古纬度分别为9.8°N及1.7°N。晚二叠世至早、中三叠世,它们先后拼合于西伯利亚及华北,有一定的向北位移,仍在热带圈内。早、中三叠世动植物群分析表明:华夏特提斯区(包括扬子省)早三叠世早期

The Early and Middle Triassic palaeogeography of lower Yangtze Basin and its evolution

The Lower and Middle Triassic rocks in the lower Yangtze basin between the North China Oldland and the Jiangnan Oldland is dealt with in this paper. Here the Lower Triassic may be divided into the Yingking, Helongshan and Biandanshan Formations, and the Middle Triassic consists of the Dongmaanshan Formation. The commonest rock type is mu-dstone, wackestone, packstone and grainstone. The palaeolatitude, palaeosalinity, palaeo-temperature, palaeodepth, palaeoslope, palaeobasin-coastline, and oldlands are dealt with in this paper also. According to the data mentioned above, the evolution of the basin from the Early to Middle Triassic is discussed herein.