THE BASEMENT STRUCTURE OF SICHUAN BASIN AND ITS RELATIONSHIP TO THE OVERLYING SEQUENCES

In accordance with the parameters selected systematically from the drilling wells and the data from regional geological surveys on the border areas of Sichuan Basin, the integrated geological and geophysical interpretations for a new completed seismic profile in the basin are carried out. Thereafter, the location of the basement structure and the relationship to its overlying and underlying strata are described on the basis of the profile across the basin from Anxian to Wenshui. It concludes that the basement of the basin consists of a central ancient rigid massif and two foldbelts located at both sides of the massif with three different geological times. Based on Chinese tectonic framework, this paper completely describes the formation of the basement and the controlling factors of the basement on the deposition and tectonic development of its overlying sedimentary sequences.