Recently, the destruction of the North China Craton has become a center of active discussion in earth sciences. While its mechanism remains unclear and debatable. Moreover, geothermal research on this subject is relatively few. The Ordos Basin, located in the west of the North China Craton, is a typical intraplate tectonic unit with stable sedimentation since Paleozoic. Jurassic to Cretaceous is an important period of the formation and evolution of this basin, which were affected by the Tethyan and circum-Pacific tectonic domains. In an attempt to understand the deep dynamics of lithospheric destruction of the North China Craton, the thermal structure of a two-dimensional profile (named AB) across the Ordos Basin from west to east has been studied to provide geothermic evidence to addressing this issue. Based on the two-dimensional steady-state heat conduction equation and using the finite element algorithm, thermal modeling along the profile (named AB) across the Ordos Basin has been carried out, resulting in the lithospheric thermal structure in the Ordos Basin west of the North China Craton. Furthermore, in the process of simulated calculation, we constantly adjust the heat flow at the bottom of the model to calculate surface heat flow (named calculated surface heat flow), which will be used to fit the measured heat flow on the surface of the earth. So the simulation results are convinced because they are constrained by both thermal physical parameters and the measured surface heat flow. The results are as follows: (1) The Moho temperature along the profile ranges from 610 degrees C to 700 degrees C. The temperature in the east is higher than that in the west. (2) Mantle heat flow values in different tectonic units in the Ordos Basin range from 21. 2 to 24. 5 mW . m(-2). In the eastern Ordos Basin mantle heat flow values are high while the values in the western region are relatively low. But mantle heat flow values are smooth and not high overall, showing a stable deep thermal background in the west of the North China Craton. (3)The 'heat flow ratios of crust to mantle(Q(c)/Q(m))along the profile are between 1. 51 and 1. 84, which indicates a 'thermal state of relatively hotter crust while colder mantle. (4) In the west of Ordos Basin, the thermal lithospheric thickness is about 160km, while in the east it is about 140km. They both indicate that the Ordos Basin has a thick thermal lithospheric root. By the lithospheric thermal structure study, we find that the Ordos Basin, located in the west of North China Craton, is in a relatively stable deep dynamic environment. Moreover, we focus on the disparity in thickness between the thermal and seismic lithosphere. The difference between seismic and thermal lithosphere thicknesses in the western Ordos Basin is about 140km, which decreases gradually from the Fenwei graben in the eastern Ordos Basin to the Bohai Bay Basin farther east. That is to say the differences between seismic and thermal lithosphere thicknesses decrease gradually from the west to the east of North China Craton. The simulation results imply that viscosity of the asthenosphere under the North China Craton decreases gradually from west to east, confirming that dehydration of the Pacific subduction plate likely has a great effect on the North China Craton. Combining previous results and this study, we suggest that convection erosion and peridotite melting in the big mantle wedge formed by the Pacific subduction under the eastern North China Craton are the dynamic mechanisms of the destruction of the North China Craton.
