摘要
在不少论著里都认为鄂尔多斯盆地二叠纪及以后的沉积为纯陆相,有人以石盒子群的沉积作为该区“内陆盆地”或盆地阶段开始的标志。但近年来积累的某些新资料使研究者认识到:至少到早三叠世鄂尔多斯与海还有相当密切的连系,常受海泛波及;甚至到中侏罗世,鄂尔多斯也不宜称为“内陆盆地”。一、石盒子群和孙家沟组的海相层 1.上石盒子组的海相层近年来,在鄂尔多斯西缘(如贺兰山沙巴台、桌子山南端的公勿素等)上石盒子组内发现某些特殊的岩层——在野外定名的“硅质岩或硅质泥岩”中发现了生物碎屑岩。
The marine sediments of the Upper Shihezi and Sunjiagou Formations have been found in these years on the eastern, southern and western margins and in the northwestern part of the Ordos Basin. It is inferred, from the relations between the salinity and palaeoclimate as well as the fossils of cartilaginous fishes,that the sediments from the Yanchang Group, even the Yan'an Group were once subjected to transgression, and that the Ordos Basin was either a nearshore plain influenced by transgression at times, or a lake associated with seas rather than a so-called 'interior' from Late Permian to Mid-Jurassic.
出处
《沉积与特提斯地质》
CAS
CSCD
1990年第5期8-12,共5页
Sedimentary Geology and Tethyan Geology
