ANALYSIS OF CENOZOIC TECTONIC EVOLUTION AND ITS DYNAMIC BACKGROUND OF THE JIYANG DEPRESSION

The balanced section method is adopted to calculate the directions of the first principal tensile stress during Cenozoic period in Jiyang depression. The result shows that the principal stress direction is NNE during Ek-Es₄, NNW during Es₃₊₂, NWW during Es₁-Ed, and N-S in Neogene and Quaternary. The first principal stress directions are closely correlated with the fault activity, tectonic interface changing and subsidence history of the basin. The Jiyang depression is a composite basin which is dominated by rift and superimposed with strike slip. The basin has experienced four stages, namely, rift plus strike slip, strike slip, rift, and depression.