大别-胶南造山带温泉中天然气地球化学特征

GEOCHEMICAL CHARACTERISTICS OF NATURAL GASES IN HOT SPRINGS IN DABIE-JIAONAN OROGENIC BELT

大别－胶南造山带温泉气中的CO2含量较低（多数在1．00％以下）．δ13C变化范因为－20．34‰至－3．0‰，主要为源于地壳浅层的有机成因气。整个造山带各温泉气体成分均以N2为主（90％左右），其来源除大气N2以外，可能为地壳岩石释放或地层中有机体演化形成。稀有气体同位素组成表明，Ar主要来源于大气，He为壳内岩石放射成因。本区温泉气体地球化学特征可能与现今中国东部的构造应力场有关，即大别－胶南造山带可能正处于紧密挤缩的构造环境，难以形成深部幔源气体脱排和运移的通道。本区温泉气的研究不仅有助于探讨天然气地质理论，而且有助于揭示造山带现今的构造运动、岩浆活动和水文地球化学特征。

The contents of CO2 in hot springs in the Dabie-Jiaonan orogenic belt are very low (mostly less than1. 00% ). The δ 13C of CO2 varies between - 20. 34‰ and - 3. 0‰, characteristic of organic gas fromshallow level of the Earth's crust. N2 is a major gas (90% or so) in hot springs in the whole orogenic belt,which is probably released by rocks in the Earth's crust or derived from organic evolution in strata in addition to the atmosphere. The isotopic composition of noble gas indicates that Ar stems from the atmosphere,and He is of radioactive genesis. The geochemical characteristics of gases in hot springs in the work areamay have some relationship with the tectonic stress field in eastern China, i. e., the Dabie-Jiaonan orogenicbelt possibly in firmly compressional tectonic setting which blocks up the discharge channel-ways of gasessteming from the mantle. Studies on gases from hot springs in this area contributes not only to the enrichment of geological theory of natural gases, but also to revealing the tectogenesis, magmatic activity and hydrogeochemical characteristics of the orogenic belt nowadays.