【摘要】 讨论了赣南横迳地区温泉逸出气体的化学组成及比率和氦、碳同位素组成及其特征.结果表明:横迳地区地热气体主要成分是CO2,占总体积的96.47%~99.84%,属CO2型温泉气,其1δ3C值变化于-5.50‰~-4.43‰,符合岩浆-幔源无机成因;CO2/3He比率为6.35×107~1.02×109,符合我国东部火山活动区幔源气体低CO2/3He比率特征,并预示可能存在不同的气床;CH4/3He比率为2.38×107~5.3×108,大于幔源CH4的表征值5×106,说明横迳地区温泉气体的CH4是非幔源成因;3He/4He比值分别变化于1.90×10-6~2.95×10-6,R/Ra为1.36~2.1 l,具有明显的幔源成因,且幔源氦占总氦比例为16%~26%,显示温泉氦气壳-幔源复合型成因.更多还原

【Abstract】 Based on the chemical composition,helium and carbon isotopes of geothermal gas in Hengjiang area,southern Jiangxi province,the characteristics of compositions and isotopes of geothermal gas are studied.The results show that the major gas from the hot springs is CO₂,amounting from 96.47% to 99.84% of the total gas volume.Accordingly,the type of geothermal gas is CO₂ type.The δ¹³C values of CO₂ range from-4.43‰ to-5.5‰. The source of CO₂ is considered to be from mantle.The CO₂/³He ratios of 6.35×10⁷ to 1.02×10⁹,are in accordance with the characteristic of mantle gas in East China.Moreover,there are possibly different temperature gas fields in depth.The CH₄/³He ratios vary from 2.38×10⁷ to 5.3×10⁸,considerably greater than 5×10⁶ for the mantle,indicating that CH₄ is not mantle origin.The ³He/⁴He and R/R_a ratios,changing from 1.90×10^-6 to 2.95×10^-6 and from 1.36 to 2.11,respectively,suggest that 16% to 26% helium can be derived from mantle.Therefore,the helium can originate from the mixing of crystal and mantle sources.更多还原