俯冲带深部碳循环:问题与探讨

Some Problems of Deep Carbon Cycle in Subduction Zone

碳循环可以分为地球表层短周期的地表碳循环和地球内部长周期的深部碳循环。地球的碳90%以上是赋存在固体地球内部,因此深部碳循环研究对于探讨地表碳循环过程具有重要意义。本文较深入地探讨了俯冲带深部碳循环研究的现状和问题。目前俯冲带深部碳循环研究关键的科学问题包括:(1)俯冲带变质过程中含碳物质相的转变,(2)俯冲带脱碳机制,(3)俯冲带深部碳循环和地幔交代作用。俯冲带变质过程中含碳物质相的转变是深部碳循环研究的最基本问题,将是深部碳进一步研究的重点。俯冲带脱碳机制主要包括纯变质反应脱碳、流体溶解脱碳(流体渗透作用)、熔融作用脱碳和氧化还原反应脱碳4个方面,这是目前深部碳循环研究的前沿领域。俯冲带深部碳循环研究对于探讨地幔不均一性以及地幔交代过程都具有重要研究意义。

Generally, the carbon cycle in the Earth system can be divided into the short-term surface carbon cycle and the long-term deep carbon cycle. Because〉90% carbon content is stored in the deep Earth,the deep carbon cycle is a key to understand the origin and process of surface short-term carbon cycle. Three aspects problems such as the metamorphic transformation of carbon-bearing phase in subduction zone, the mechanism of decarbonization and mantle metasomatism have been discussed in details in this review paper. The basic problem of the metamorphic transformation of carbon-bearing phases is still needed to do the extensive research in the future. The decarbonization mechanism including decarbonizing metamorphic reaction,carbon dissolution or fluid infiltration, melt decarbonizing and carbon redox reaction should be the research frontiers＇ in deep carbon cycle. Meanwhile,the study of deep carbon cycle in subduction zone is very significance for understanding the geochemical mantle heterogeneity.