早二叠世亚洲中轴大陆区的中朝地块及北亚大陆区的西伯利亚地块之间,有一条近东西向分布的地带称北亚陆间区,其东部属内蒙古海槽,横贯我国北方各省,东西绵亘3000余公里、地层分区属天山—兴安区(图1)。 由于北部西伯利亚古陆和南部中朝古陆的隔绝,西部又被准噶尔和塔里木隆起所阻塞。因此,推测本区海盆只能由东和东北部与外界沟通。整个早二叠世时,以北极海水为主,自东北进入,漫布区内,呈一西端尖缩、东端开阔的楔形海域,其中发育了海相及局 North-Central Asia block in the Early Permian and the Siberian block in the North Asian continent, a nearly east-west distribution belt called the North Asian continental zone, the eastern part of which belongs to the Inner Mongolia Trough, runs through our country Northern provinces, things spanning 3000 kilometers, strata sub-Tianshan - Xing’an District (Figure 1). Due to the isolation of the ancient Siberian land in the north and the ancient Sino-North Korean land in the south, the west was blocked by the Junggar and the Tarim uplifts. Therefore, it is speculated that the basin in this area can only communicate with the outside world from the east and northeast. The entire Early Permian, the Arctic seawater mainly from the northeast into the diffuse area, was a western end of the constriction, the eastern end of the open wedge-shaped waters, in which the development of marine and Bureau