Features Of Structure Deformation And Evolution Of Mesozoic-Cenozoic Basins In Eastern Heilongjiang

The nature of prototype of the Mesozoic-Cenozoic basins in eastern Heilongjiang and their tectonic eovlution have become some critical basal geological questions, which may in turn restrict further hydrocarbon exploration in this area. This paper is conducted the study on characteristic of filling and defromation, structural evolution of the basin groups in the eastern Heilongjiang based on the comprehensive analysis on geological data obtained from field geological survey, and exploration data including drilling, logging, seismic data collected from Daqing oil-field. Evolutinary stages of each basin have been divided and the evolutionary histories also have been restored. Finally, the nature of basin prototype and their geodynamic setting were discussed. Some conclutions can been drawn as follows:1, Four important regional unconformities can be identified from the Mesozoic-Cenozoic basins in the eastern Heilongjiang:Middle Jurassic/Pre Jurassic, Upper Cretaceous/Lower Cretaceous, and Paleogene/Cretaceous. Then four main tectonic layers can be divided according to these four unconformities:Middle-Upper Jurassic structural layer, Lover Cretaceous structural layer, Upper Cretaceous structural layer, Cenozoic structural layer.2, Mesozoic-Cenozoic basins of eastern Heilongjiang have experienced four major stages: Middle-Later Jurassic rift-depression, Early Cretaceous rift-depression, Later Cretaceous local depression, and Paleogene rift-Neogene depression. The basins have suffered three stages strong compression transformations during the end of Later Jurassic, Early Cretaceous, Later Cretaceous, and weak compression-extension during Cenozoic. compressional structure is the most common and the main structural style in Mesozoic-Cenozoic basins of northeastern Heilongjiang.3, During the deposition stage of the Didao Formation, the eastern Heilongjiang was characterized by rifting and formed some isolated faulted-depressions. A huge sag developed in this region during the sedimetation of the Chengzihe and Muling Formations. at the end of early Cretaceous (after deposition stage of Mulin Formation), bimodal volcanism occurred and the volcanics formed the major of the Dongshan Formation. 4,The compression transformation event during Later Cretaceous is mainly transformation event of basins in eastern Heilongjiang. The end of Early Cretaceous, all the basins were suffered the first compression deformation, uplifting and erosion during the early of Later Cretaceous, a little depressin developed along some small mountains, formed the Houshigou and Hailiang Formations, At the same time, the east of the Sanjiang basin was deposited by Qixinghe and Yanwo Formations. Finally, a strong compression phase resumed and all the basins were destroyed again and formed some isolated residue basins untill now.5, The tectonic evolution of Mesozoic-Cenozoic basins in the eastern Heilongjiang is the shallow response of lithosphere for the interaction between Western Pacific and the Eurasian continental plates. Local mantle convection and back-arc extension in eastern Heilongjiang during the Mesozoic-Cenozoic is the main dynamic model, which may result from the subduction of Pacific Plate along Eurasian continental margin.This study is helpful in understanding the basin-forming and transformation of basin in eastern Heilongjiang basin and the Mesozoic-Cenozoic regional geological evolution in Northeast Asia.