A Preliminary Research On The Geothermal Resource In The Xilinhot City And Its Surrounding Areas Of Inner Mongolia

Xilinhot City is a typical area of volcanic geothermal anomaly in northern China.Now, the degree of research in the area of geothermal resources is very low, basicallya blank area of geothermal research. With the development of society and economy,especially for the scale development of tourism, it is urgently needed to carry outresearch on the development conditions of geothermal resources exploration in urbanand surrounding areas. Therefore, the study has important academic significance andsocial value.The study consists of the following three steps. First of all, according to theregional geological data collection and field reconnaissance and other means, at thesame time combining the previous geophysical exploration and drilling data, weanalyzed the landform, stratum lithology, fracture structure, hydrologic geology,geological conditions in study area and basically grasped the geophysical survey.Then, by collecting water samples in the field, laboratory testing, water quality andgeothermal iconic components classifying and stable isotope analyzing, etc., weanalyzed the hydrogeochemical characteristics in the study area and preliminarilydelineated the geothermal anomaly area. Finally, combining with the geophysical andhydrogeochemical conditions, the geothermal geological conditions in the study areawere comprehensively analyzed from the “heat, cover, storage, connection” four basicelements and the preliminary evaluation on the geothermal resources was made.The research shows that: the region has the basic conditions of geothermalresources occurrence. The heat source mainly comes from the heat released from themantle and bedrock. The cover is the Quaternary, Tertiary, Cretaceous and partlyJurassic formations and the insulation layer is mainly the Cretaceous strata. Affectedby new cathaysian tectonic system, deep fractures which along the direction ofnorth-east, north-west and east-west are likely exist in this area and form theunderground hot water upwelling channels.In addition, the thermal storage situation is preliminarily evaluated in the study as follows: there may be two different heat storage in the north and south sides ofXilinhot, the pore type (K) and the tectonic fracture type (Pz).(1)The pore thermalstorage is distributed on the fault basin on the the northern side of urban areas. Thereare two heat reservoirs in this area:①Cretaceous sandstone and sandy conglomeratelayers, depth of less than1600m, porosity is between10%～20%, but the water yieldis not large, the salinity is relatively high, so the exploitation conditions are general.②The yield of fracture-karst water in Paleozoic carbonate rocks of buried hillunderlying the cretaceous strata is better, but the buried depth is larger (more than2000m) and the salinity ranges from3.5to13.5g/L. This water can be used formedical mineral water.(2) structural fissure heat reservoir is mainly distributed inbedrock fissure water area in the south of urban area. There are granite intrusionsShallow concealed at depth of400～500m. The thermal storage in the form offracture belt occurs in granite rock fractured zone which controlled byShangdewenduo thrust fault and limekiln normal fault. The quality and quantity ofwater is good. This water has good workability.