Gravity-magnetic anomalies and tectonic activities in Luxi uplift

Luxi uplift has complex geological conditions and well-developed faults. By analyzing and calculating the gravity and magnetic data in this area, we studied the characteristic of gravity-magnetic anomalies, Moho discontinuity and Curie isothermal surface on the Yishu fault zone, Qihe-Guangrao fault zone, Liaocheng-Lankao fault zone, Fengpei fault zone and the uplift block, as well as the geological tectonic features and tectonic activity of this area. The results show that basement of Luxi uplift is widely exposed, and sediments are mainly distributed in the sags which are controlled by the down-thrown side of faults. Faults depth of this area can reach up to more than 20 km, and one of them is a regional upper mantle deep structure named Mengshan fault. Meng-shan fault controls output of the kimberlite-type diamond. The depth of Moho discontinuity in this area varies from 30 km to 35 km, and it features a dustpan shape which is open to the west. The central block is thick and the surrounding areas are gradually thinning except for the west part which is stepped thickening. The Curie isothermal surface depth ranges from 20 km to 33 km with an average of 26 km. The Curie depth of the central area is deeper than its surrounding areas, and it is a stable block. The fault zones correspond to the Curie surface gradient zones. The earthquake activities mainly focus on the areas where the fault zones meet with Moho discontinuity gradient zones, as well as the fault zone where Curie surface changes abruptly.