Study On Genetic Mechanism of Geothermal System In Mishan Area Based On Electrical Structure

Dunhua-Mishan Fracture Zone is a large-scale lithospheric fault with long development history and many active periods in Northeast China. It is a good prospective area of geothermal resources.In order to scientifically evaluate the geothermal resources in the study area and study the genetic mechanism of the regional geothermal system, this paper uses AMT(audio-magnetotelluric sounding) to carry out the pre-feasibility exploration of geothermal resources in Mishan City, and obtains the 2-D electrical structure shallower than 4000m beneath Mishan city.The comprehensive geological interpretation combined with regional geology and hydrogeology shows that the development prospect of hydrothermal geothermal resources in Mishan area is good:(1)A high resistivity body in the Cretaceous strata of Mishan city is speculated to be a strongly weathered intrusive rock with high radioactivity and strong heat conduction capacity, providing a good heat source in the geothermal system.(2)The sedimentary stratum broken due to intrusion action is an suitable water storage layer, with a thickness of about 1500m and a large amount of energy reserves.(3)The Tertiary mudstone and glutenite strata in multi-layer integrated contact have good water and heat insulation performance, and the thickness is more than 200m, making it a very ideal caprock.