晚二叠世至中侏罗世鄂尔多斯盆地与海区关系的讨论

RELATIONSHIP BETWEEN THE ORDOS BASIN AND SEA AREA FROM LATE PERMIAN TO MID-JURASSIC

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”。

Abstract: 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.