地热区深部碳的地球化学研究综述  

Deep carbon cycling in geothermal areas: A review

作　　者：李长正 郑国东 郭清海 楠本成寿 王焰新 LI ChangZheng;ZHENG GuoDong;GUO QingHai;KUSUMOTO Shigekazu;WANG YanXin(MOE Key Laboratory of Groundwater Quality and Health,School of Environmental Studies,China University of Geosciences,Wuhan 430074,China;Geothermal Institute of Kyoto University,Beppu 874-090,Japan)

机构地区：[1]中国地质大学(武汉)环境学院,地下水质与健康教育部重点实验室,武汉4300742.京都大学理学研究科地球热学研究所,别府874-090

出　　处：《岩石学报》2024年第7期2255-2266,共12页Acta Petrologica Sinica

基　　金：国家自然科学基金国际(地区)合作与交流项目(42261134534)资助。

摘　　要：碳是地热流体中普遍存在而且非常活跃的生命元素。自地幔源区释放的深部碳运移至近地表的过程中,碳元素有可能记录了许多源区信息以及混合分馏过程的特征,尤其是在地热分布区。因此,与地热区深部碳释放相关的地球化学研究对联系岩浆热源型地热系统深部热源和浅部高温流体的物质交换和运移以及准确判断地热地质背景等都具有非常重要的意义。目前,国内外学者对加深地热流体挥发分来源的定量研究以及完善地热区同位素分馏理论等方面都做出了许多探索性的尝试,其中对来自深部的碳元素的研究是最重要的课题之一。对深部碳俯冲循环过程与地幔源区非均一性特征,地热区岩浆脱气、方解石沉淀、气体溶解脱气的分馏特点、围岩变质脱气与土壤碳的混合过程及其规律等的系统分析结果显示,深部碳的释放经历了复杂的地球化学过程。由于单一方法的研究难以全面揭示该过程,本文通过对该领域相关研究方法的梳理和融合,结合地热区深部碳释放的规模和方式的总结,以期为地热系统物质运移规律和地热流体碳来源的定量研究提供参考和支撑,促进对深部碳循环过程及其气候环境效应的把握和认识。Carbon is a ubiquitous volatile found in geothermal fluids.During the migration of carbon released from the mantle to the near surface,i.e.the carbonate precipitation or magma degassing,its isotopic signature allows to obtain precious information on the source of carbon(organic vs.inorganic),fluid mixings and mass fractionation processes.Therefore,geochemical characteristics of deep carbon release processes in geothermal areas are of great significance for understanding the migration of deep-sourced heat and high-temperature fluids in magma-heated geothermal systems.Numerous studies have been attempted to quantify the source of volatiles in geothermal fluids and disentangle isotope fractionation processes in geothermal areas using carbon isotopes.These processes are related to mantle source heterogeneities,magma degassing,calcite precipitation,gas dissolution or degassing,metamorphic processes,mixing of shallow soil/organic carbon sources,etc.These processes are too numerous and often overlapping to be easily discriminate.Therefore,it is urgent to summarize the methodologies used for disentangle these various processes to provide a reference or studies of carbon in geothermal systems.In order to promote further understanding of the deep carbon cycle process and its climatic and environmental effects,the characterization and scale of deep carbon emissions in geothermal areas are briefly reviewed in this paper.

关 键 词：深部碳 地热流体 碳同位素 定量研究 

分 类 号：P314[天文地球—固体地球物理学] P317[天文地球—地球物理学]