The sequence pattern and controlling factors in terrestrial rift-subsidence lacustrine basin——Taking the Shanhejie Formation of Lower Tertiary in Huimin Depression as example

Huimin Depression is a typical terrestrial rift-subsidence lacustrine basin.The study results indicate that the 2,3 and 4 sub-members of Shahejie Formation of Lower Tertiary can be divided into three types of stratigraphic sequences, i. e. the stratigraphic sequence in primary rifting stage, the stratigraphic sequence in violent rifting stage and the stratigraphic sequence in the later rifting stage.The sequence stratigraphy indicated that it is more suitable to divide a sequence into four system tracts. The red beds stratigraphic sequence is mainly controlled by the climate and has unique characteristics in sequence evolution. The three kinds of stratigraphic sequence in this region formed three kinds of condensed sections that located in different section of each sequence.The different condensed section will influence the abundance of source rock and resources,and every condensed section controls the distribution and thickness of the source rock.