黑龙江东部中-新生代盆地演化

黑龙江省东部中-新生代盆地基底由佳木斯地块和完达山地体复合而成.佳木斯地块以加里东期变质岩及花岗岩为主,东缘发育晚古生代和早中生代大陆边缘沉积.完达山地体在中-晚侏罗世就位在佳木斯地块东缘,并在早白垩世早期逆冲到佳木斯地块之上,形成具有前陆盆地性质的大三江盆地.大三江盆地在早白垩世晚期遭受逆冲、走滑构造改造.敦密断裂以北的诸多盆地均属大三江盆地改造后的残余盆地.这些残余盆地和完达山地体之下可能存在隐伏的晚古生代和早中生代大陆边缘沉积.三江盆地东部是古近纪断陷的主要发育区,可能存在一与佳依地堑平行的深断陷.隐伏的大陆边缘沉积和断陷是值得重视的油气勘探领域.

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.