Hydrogeochemical Characteristics And Its Origin Analysis Of Geothermal Water In The Qia Bu-Qia Area, Gong He Basin, Qing Hai Province

The paper took the geothermal water of Qia Bu-qia area, Gonghe basin, Qingh ai Province as the study object. On the basis of geothermal geological conditions, t he paper analyzed and studied hydrogeochemical characteristics, isotopic characteristi cs and its origin of geothermal water in the study area. And main knowledge and conclusions have been obtained as follows:(1)There are hot springs or geothermal water near the fault zone and the water temperature is 26-42℃, which indicates that these faults cut deeply and providesa good channel for the deep geothermal energy and underground water movement.(2)The chemical grouping of geothermal water is obvious and is different from the cold groundwater and river water. The cold groundwater and river water arem ostly compound water, named HCO3-Ca·Mg·Na and HCO3-Na·Ca·Mg. But the main hydrochemical types of the geothermal water is SO4-Na,Cl SO4-Na and Cl-Na.(3)The geothermal water in the southeastern and central study area has higher TDS, which shows that the TDS gradually become larger as the runoff path increas e. The result agrees to that water-rock reaction is fiercer as the temperature increas es. Part of the geothermal water temperature is relatively high, but the TDS is relat ivelylow, it may be because there are cold water mixed.(4)The geothermal water supply comes from the glacier snow melting water in the north of Qinghai mountain, and the replenishment elevation is 4135.56Km~4961.38 Km.(5)The reservoir temperature of the Quaternary geothermal water in the study a rea is probably 33.85~66.43℃ and the depth of circulation of geothermal water is 1-2.5Km; The reservoir temperature of the tertiary geothermal water in the study ar ea is probably 94.71~140.24℃ and the depth of circulation of geothermal water is 3~4.5Km.(6)The main source of the geothermal water in the study area comes from the Western aquifer and Northern Alpine snowmelt and the heat source mainly comes f rom the deep mantle heat conduction. In the South and the east part of the study a rea, because of the existence of the fault zone, the heat energy exists in the form of convection.