Cenozoic volcanism in Northeast China and its implications for geothermal systems
Lijuan He , Jinhui Wu, Chaoqiang Chen, Yibo Wang
Affiliations: State Key Laboratory of Lithospheric and Environmental Coevolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China
Presentation type: Poster
Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall
Poster Board Number: 4
Programme No: 5.1.10
Abstract
Since the Cenozoic, volcanism in Northeast China has been distributed along the periphery of the Songliao Basin, while there has been no volcanism within the Songliao Basin, which has attracted extensive attention from researchers. To explain such phenomenon, a 2D visco-elasto-plastic model is established to model the ascending process of intraplate magma through the lithosphere, and study the influences of the lithospheric thermal-rheological structure on magma movement. The numerical simulation results indicate that with the increase of the temperature of the Moho (Tm), magma migration presents four situations: 1) at low Tm, the cold rigid crust will hinder magma ascent; 2) As Tm increases, the crust weakens, and magma directly penetrates the crust and erupts from the surface; 3) At appropriate Tm, magma invades the upper crust, forming hidden magma chambers that heat the surrounding rocks until the magma has completely cooled down; 4) at high Tm, magma will only extend laterally at the bottom of the crust. Situation 3) is most conducive to the formation of magma-type high-temperature geothermal systems. Additionally, we calculated the lithospheric thermal structure based on heat flow data and showed that Tm in the Songliao Basin is very high, much higher than its surrounding areas, which maybe an important reason for the lack of Cenozoic volcanism within the basin. Nonetheless, the high heat flow and the hot crust are favorable for the formation of low-medium temperature geothermal system of conductive type in the basin.