The distribution characteristics of CO2
and their carbonisotope in the hot water of the deep well in central Hebei area have been presented.Therefore,the sources of the inorganic carbon chemicals dissolved in the ground water has been analyzed by their δ13
C value.The results have shown that the dissolved inorganic carbon in the ground water in the base rock in central Hebei depression are mainly from metamorphic action of the carbonate secondly from imbibing of CO2
in the soil and the air following the ground water.Otherwise, No.20 well in Huanghua depression in Changxian rise and XU No.7 welJ have,except above sources,CO2
causing from bio-chemical action.The inorganic carbon chemicals from metamorphic action in central Hebei is possibly sensitive factor for earthquake precursor and priority to the selection in the geochemical surveilance.