Characteristics Of Boundary And Evolution Of Cretaceous Basins In Eastern Heilongjiang Province

This paper selects the Cretaceous basins in eastern Heilongjiang Province as a target, based on region data and geophysical data collected from field, to discuss the boundary and the basic law of basin evolution. It may be important for theory and have practice value for deepening fundamental geology and geophysics in Northeast of China, studying basin geology and oil & gas perspective evaluation surrounding Daqing.The basins refered in this paper include Sanjiang basin, Boli basin, Jixi basin, Hulin basin. In order to obtain the first hand data, several field section were setted and done. And it's necessary to check the dependability of the data because of many influence factors, so some works were done:1. Using the confirmed material of Hulin basin which include Bouguer gravity anomaly, faults distributing, tectonic structure and property of base, to make a compare with the inversion result of gravity. And they are consistent clearly.2. Using the depth of base in seismic section to check the result of gravity inversion. There are three cross points in Hulin basin and two in Tangyuan fault-depression, and the difference are between 60m and 20m, which is in the permissibility range. 3. Using the match of tectonic structure which are form seismic section and gravity inversion and telluric electromagnetic sounding to identify. Two concaves and one convex are found in superposition of Line 96-M.0 and Line DB5.Boundaries of those basins are concluded, which is based on synthesizing materials of geology and geophysics, and base shape, rupture characters from inversion of gravity and tectonic structure form inversion of telluric electromagnetic sounding. Dunmi Fault is the southeast boundary of Jixi basin and the fault in south of Nadanhada Upheaval is the south boundary. The west one is denudation. In Boli basin, there are Boli Fault in the southeast, River-Qitai Fault in the north, and Boxi Fault in the east. The two above basins are divided by the Nadanhada Upheaval. The south boundary of Hulin basin enters into the Lake Xingkai and the north is Dunmi Fault. Yilan-Yitong Fault is the west boundary of Sanjiang basin, and Dahezhen Fault which divides the Qianjin Depression and Mountain Wanda Upheaval is the east one.According to the map of tectonic development and forward materials, it is a fault stage in Didao Formation, and it is a sag stage in Chengzihe Formation and Muleng Formation; it is a part fault stage in Dongshan Formation and an extrusion atrophy stage in Houshigou Formation and Hailang Formation. Tectonic inversion happened under the influence of EW thrust fault in late Cretaceous to Tertiary. Nowadays there are a relic basins in the eastern area of Heilongjiang Province.