EVOLUTION OF MESOZOIC-CENOZOIC BASINS IN THE EASTERN HEILONGJIANG PROVINCE, NORTHEAST CHINA

The basement of the Mesozoic-Cenozoic basins in Eastern Heilongjiang Province, Northeast China is composed of the Jiamusi massif and Wandashan allochthon (terrane). The former consists of the Caledonian metamorphic rocks and granites covered by unmetamorphosed Late Paleozoic and Early Mesozoic continental margin sediments in the east margin. The latter, as an allochthon, was situated on the east margin of the Jiamusi massif during Middle to Late Jurassic, and overthrusted westwards on the Jiamusi massif in initial Early Cretaceous. Therefore, an Early Cretaceous foreland basin (namely Pan-Sanjiang basin) was formed in the area. The Pan-Sanjiang basin was destroyed and reconstructed by the thrust and strike-slip faults in the later stage of Early Cretaceous. We suggest that all isolated basins to the north of the Dun-Mi Fault belong to the relict basins of the Pan-Sanjiang basin. According to the regional geological setting, it is possible that the Late Paleozoic and Early Mesozoic continental margin sediments would be preserved under these relict basins and the Wandanshan terrane. The east part of the Sanjiang basin is an important area, where Paleogene faulted basins are developed and a deep major faulted basin parallel to the Jiayi faulted basin exists probably. These covered continental margin sediments and faulted basins are worthy to be considered as the new field of oil and gas exploration.