Tectono-thermal modelling of sedimentary basins with episodic extension and inversion, a case history of the Jiyang Basin, North China
A two-dimensional kinematic model is presented for superimposed basins. It is based on a finite element algorithm in the Lagrangian system, which incorporates different stages of lithosphere stretching and shortening to simulate alternating extension and inversion. The Jiyang Basin, developed in the North China, is a superimposed basin comprising four proto-type basins separated by several unconformities. Four-phase extension and two-phase inversion have developed in this basin since the Late Mesozoic era. The thermal history of the basin is modelled based on a seismic cross- section across the basin. Tectonic subsidence (or uplift) histories from backstripping serve as the objective functions, and crustal thickness, as well as heat flow, provides additional constraints. Effects of different Mesozoic erosion on the thermal history are discussed. Modelling results show that the thermal history of the Jiyang Basin since the Late Mesozoic can be divided into six stages, including four phases of heating accompanied by following thermal attenuation, and two phases of cooling with following thermal recovery. The model also implies a variant pattern of thermal regime in the basin. In the deepest centres of the depressions, the maximum heat flow occurred during the Late Mesozoic, but in the slopes of the depressions, the maximum heat flow appeared in the Cenozoic era.