A RELATIONSHIP BETWEEN THE TAN-LU FAULTED BELT AND THE PETROLEUM GEOLOGY OF THE HEFEI BASIN

According to isotopic dating, sinistral displacement of the Tan-Lu faulted zone took place in the Early Cretaceous. The movement offset sinstrally the Dabie-Jiaonan Orogenic Belt. The displacement of the faulted zone controlled the development of the strike-slip basin in the eastern part of the Hefei Basin in the Early Cretaceous. The strike-slip basin was filled with deposits of the Zhuxiang Formation. Dark mudstone with a total thickness of 600m was deposited in the environment of deep lakes in the Early Cretaceous strike-slip basin. During extensional movement of the Tan-Lu Fault from the Late Cretaceous to the Paleogene, a faulted half-graben basin was developed in the eastern part of the Hefei Basin. It was filled with the Xiangdaopu and Zhangqiao Formation of the Late Cretaceous and the Dingyuan Formation of the Paleogene. Dark mudstone was found in the Xiangdaopu and the Dingyuan Formation, and that from the Dingyuan Formation in the Shucheng Depression has better quality. With compression movement in East China and thrusting activities of the Tan-Lu faulted zone since the Neogen, the Hefei Basin terminated its development. In terms of hydrocarbon exploration, more attention should be paid to the Shucheng and the Daqiao Depression.