Quite detailed division of the Proterozoic and Mesozoic as well as Cenozoic stratum at Hasuhai area in the Inner Mongolia is carried on with the comprehensive geophysical survey of seismic and Magnetotelluric sounding, and the geothermal cover distribution and the stratum shape are determined. The hidden fault is explained on the low resistivity, the weak reflection energy and the broken reflection event. Through generalized analysis of the geophysical investigation results obtained in this project and known geological information, geothermal borehole position has been determined over an expected hidden fault position where the buried depth of the Proterozoic marble is relatively shallow.
The geothermal is a giant and valuable resource in the earth interior. It attracts worldwide attention as one kind of green environmental protection, economical and highly effective new energy resource. The gravity, magnetic, electrical and seismic exploration, etc., have been applied the geothermal prospecting for different purposes. This paper discusses an example of comprehensive geophysical surveys for geothermial investigation at Hasuhai area in the Inner Mongolian.
The objects of the geothermal investigation at Hasuhai area in the Inner Mongolian are: to find out stratum structure, the fault position, the hot reservoir type, burying condition in the survey area, and determine a borehole position for drilling through the comprehensive geophysical surveys of the seismic exploration and the magnetotelluric sounding. The required detection depth is up to 4000m.
The survey area is located between Huhehaote and Baotou city in the Inner Mongolia, and apart from them 60km and 80km respectively.
The stratum division of the surveying area belongs to the North China stratum area, The Mesozoic and Cenozoic fault depression basin in the south belongs to the Eerduosi stratum district. The North Daqing Mountain is the ancient folded Mountain system in the Yin Mountain stratum district, which is mainly composed of the hypometamorphic rock series in Archaean and Proterozoic era and clastic rock in Jurassic Period, as well as the acid magmatic invasive rock. In the center and south is the region of no relief, which is mainly composed of the detritus deposits in Mesozoic and Cainozoic era. The marble in the Archaean era is the hot reservoir in the survey area.
The tectonic framework position in the survey area belongs to the first-order tectonic unit of the North China platform, and it strides two second-order tectonic units of Inner Mongolia platform uplift and the Eerduosi platform depression. The north belongs to the Yin Mountain fault uplift in the Inner Mongolia platform uplift centre (the third-order tectonic unit), the center and the south part belong to the Hetao fault depression of Eerduosi platform depression centre (the third-order tectonic unit). The North in the work area is the Daqing Mountain fault fold belt of the Yin Mountain fault uplift, and the center and the south part are for the Huhe depression basin. The main structure fault in the area is the piedmont fault of the Daqing Mountain (F1) (Fig.1).