Geochemical Characteristics of Gases from Typical High-temperature Geothermal Systems in China

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• 作者：Jiao Tian^a ; ^b ; ^{liyiman@mail.iggcas.ac.cn} ; Zhonghe Pang^a ; ^b
• 关键词：high-temperature geothermal system ; geothermal gas ; geochemical characteristics
• 刊名：Procedia Earth and Planetary Science
• 出版年：2017
• 出版时间：2017
• 年：2017
• 卷：17
• 期：Complete
• 页码：500-503
• 全文大小：204 K
• 卷排序：17

文摘

Gaseous components are very effective indicators of deep processes in high-temperature geothermal systems. We have chosen the Kangding, Rehai, Tatun, and Yangbajing geothermal systems, from the Chinese segments of the Mediterranean-Himalayas and Circum-Pacific global geothermal belts, to analyze and compare the geochemical characteristics of gases. Results confirm that the two geothermal belts are very different as regards deep processes. Gases of the Tatun are mantle derived, which is in agreement with its island-arc tectonic setting, while the others are located in the continental collision boundary exhibiting crustal and mantle origins to a varying extent. The geothermal gases from Yangbajing show an apparently crustal origin. The isotopic composition of CO2 and He in the Tengchong geothermal region helped to identify their mantle origins. The CO2 of the Kangding geothermal system is largely derived from limestone metamorphism with only a small fraction of He coming from deep sources, likely due to active faulting in the area.