Abstract:

Based on the seismic survey, logging data and core, this paper analysizes the development characteristics of the Shicun fault and its controlling effect on the evolution of the Bodong buried hill, and studies systematically the sedimentary facies types of the Shahejie Formation for the first time. The research shows that the evolution of the Bodong buried hill is controlled by the Shicun Fault. The rapid uplifting of the Bodong buried hill affects the sedimentary geomorphology on both two sides in the Es₄ and the lower Es₃. However it has a weak effect on the upper Es₂ and the layers above. During the sedimentary period when the upper part of the fourth Member of Shahejie Formation deposited and when the lower part of the third Member of Shahejie Formation deposited, here mainly developed delta front subfacies, prodelta subfacies, beach bar and organic bank deposition of lakeshore-shallow lake subfacies, semi-deep lake deposition and deep lake deposition. During the sedimentary period between the middle part of the third Member of Shahejie Formation deposited and the first Member of Shahejie Formation deposited, here mainly developed delta front subfacies, prodelta subfacies and organic bank deposition of lakeshore-shallow lake subfacies and so on. Under the influence of the Shicun fault and the Bodong buried hill, facies differentiation of the North and South wings can be seen in the early stage (the Es₄ and the upper Es₃) while the same in the late stages (the lower Es₂ and the Es₁).

Key words: Bodong buried hill, Shicun fault, tectonic evolution, Shahejie Formation, depositional system