郯庐断裂带温泉气体地球化学

Gas Geochemistry of Warm Springs in Tan-Lu Fault Belt

断裂构造带温泉气体成分及同位素组成特征直接指示断裂带的构造活动及水化学特征。郯庐断裂带温泉气体成分以N2 为主 (多数大于 90 % ) ,CO2 含量较低 (多数小于 1% )。δ13CCO2 在南北不同地段存在着明显差异 ,北段为 - 5.8‰～ - 7.8‰ ,CO2 主要为岩石化学成因。而中段和南段δ13CCO2 均小于 - 10‰ ,CO2 为有机成因。4 0 Ar/36Ar为 2 95～ 363,其中较低者 ( 30 0左右 )主要来源于大气 ,较高者来自地壳岩石中4 0 K的衰变。本文研究成果不仅有助于探讨断裂带不同地段温泉气体的组成及其来源 ,而且有助于揭示郯庐断裂带构造 -岩浆活动及水文地球化学特征。

The gas compositions and isotope compositions of warm springs in fault structure zones directly indicate structure activity and hydrogeochemical characteristics in the fault zones. N 2 is the major gas component (90% or so) of warm springs in Tan Lu fault belt. There is an obvious difference in δ 13 C CO 2 for different sections of the fault zone. The δ 13 C CO 2 values in northern section are -4.3‰～-7.8‰, and the CO 2 is inorganic in origin, produced by petrochemical evolution of the rocks. The δ 13 C CO 2 values in central and southern sections are lower than -10‰, and the CO 2 is organogenic. 40 Ar/ 36 Ar vary from 295 to 363, in which the lower ratios stem from atmosphere, and the higher ratios from the decay of 40 K in the rocks of the earth crust. This paper not only studies the gas compositions of warm springs in different sections of Tan Lu fault belt and their origin, but also is important in revealing the tectono magmatic activity and hydrogeochemical characteristics of the fault belt.