Structural characteristics of the Western Branch of the Tanlu fault in Bohai Sea and its control on the formation of buried hills

Abstract

The Western Branch of the Tanlu fault in Bohai Sea refers to the Western Branch fault of Bohai segment of the Tanlu fault, the formation and evolution of which plays an important role in controlling the distribution of pre Cenozoic strata and the development of the structure of buried hills.Based on the data of 3D seismic, drilling and experimental data, the structural characteristics, genetic evolution model of the Western Branch of the Tanlu fault in Bohai Sea and its control on the formation of buried hills are analyzed.The results show that: ①the Western Branch of Tanlu fault in Bohai Sea is characterized by multi-stage superimposed activities in Indosinian, Yanshanian and Himalayan.The activation of late Himalayan is weak, and it is concealed under Cenozoic sediments.②The Western Branch of the Tanlu fault in Bohai Sea is divided into three segments: north, middle and south by nearly EW trending fault.There are some differences in the structural deformation patterns and strength of each segment in the key geological period.③The Western Branch of the Tanlu fault in Bohai Sea was originated from strike slip transition caused by uneven N-S compression in Indosinian.④Indosinian-Yanshanian strike slip thrust and associated folds in the Western Branch of the Tanlu fault in Bohai Sea are the key factors controlling the distribution of strata buried hills and the formation 19-6 buried hill structures of Bozhong.The research results can provide a basis for oil and gas exploration in Bohai Sea.

Keywords

• bohai sea
• tanlu strike slip fault zone
• indosinian
• yanshanian
• buried hill
• tectonic evolution