Cenozoic tectonic inversion in the Northern Depression, South Yellow Sea Basin, East Asia: Structural styles and driving mechanism

Abstract

The Northern Depression of the South Yellow Sea Basin underwent two episodes of tectonic inversion from the latest Eocene to Oligocene and in the Pliocene, respectively. During the inversion, the structural depression controlled previously by extensional faults was subjected to compression and erosion. Structural interpretation on 2D marine seismic data suggests that the structural styles associated with inversion are predominantly reactivated NNW-trending faults, fault-related folds, newly-formed reverse faults and unconformities. Here we used structural restoration technique to illustrate the sequential development of these inversion structures and to estimate the amount of deformation. To explore the mechanism of the basin inversion, the finite element modeling was employed to reproduce the inversion deformation in the Northern Depression. The deformation features predicted by modeling are well consistent with our structural observations. Based on a combination of these results and regional tectonic history, we propose that the inversion deformation in the South Yellow Sea Basin was predominantly driven by the enhanced dextral strike-slip motion along the Tan-Lu Fault. The interactions between the Eurasian plate and the Pacific realm resulted in the varying dextral movement along the Tan-Lu Fault, and the Cenozoic tectonic inversion in the South Yellow Sea Basin was a tectonic response to these processes.