PALEOCLIMATE RECORD OF GEOTHERMAL WATER FOR LAST 0.03 Ma IN NORTH CHINA
Yao Zujin(Institute of hydrogeology and Engineering Geology, MGMR, Zhengding 050803)
Low-temperature geothermal water is in fact ancient precipitation which circulates deeply through underground and contains information about paleoclimate variation. In the northern part of the North China Plain,in general,the geothermal water is of 40-60℃ and of 500-1500m below the ground surface. Based on regime pattern of various aquatic chemistry,the author has documented that the interaction between rock and water within the reservoirs has little impact on oxygen isotopic composition of geothermal water. The author has also examined the reliability of it data of geothermal water with geological criteria. Based on 14C and oxygen isotopic data of 40 geothermal water from literature,a relation curve has been completed,showing the paleoclimatic dry-cold or wet-warm changes since last glacial period. That tendency and turning time of the paleoclimate change coincide with some paleoclimate records from loess, deep sea deposits and lacustrine deposits at Qinghai-Tibet Platheu.