摘要
碳在地球表层和内部圈层之间的循环控制了地球的环境气候变化。海底热液蚀变以及变质作用会使得碳酸盐沉淀到玄武质洋壳中,之后它们在俯冲带经历高压榴辉岩相变质作用会形成碳酸盐化的榴辉岩。俯冲过程可以将这些碳酸盐化的玄武质洋壳榴辉岩带入深部地幔,从而导致地幔在地球化学和岩石学上存在显著的不均一性,并深刻影响着包括部分熔融在内的地幔深部动力学过程。早期对碳酸盐化榴辉岩的实验研究多集中在俯冲带地温梯度下碳酸盐化洋壳榴辉岩的命运,近年来的实验开始研究地幔温压条件下碳酸盐化榴辉岩部分熔融对板内碱性玄武质岩浆源区的潜在影响。本文简要梳理了碳酸盐化榴辉岩在上地幔温压条件下的部分熔融实验,并结合一些天然样品的研究实例,说明碳酸盐化榴辉岩熔体不仅可以作为潜在的地幔交代介质,还可能是板内碱性玄武岩源区的重要组分,它们与橄榄岩发生反应或者与橄榄岩熔体发生混合可以解释板内碱性玄武岩的成分变化。
Carbon cycle between the Earth s surface and interior controls Earth s climate change.Hydrothermal alteration and metamorphism in the ocean floor will sequester carbonate into the basaltic oceanic crust,and the carbonate-bearing altered oceanic crust will be metamorphosed and transformed into carbonated eclogite in the subduction zone.Carbonated eclogite may be subducted into the deeper mantle,resulting in geochemical and petrological heterogeneity of the mantle,and profoundly affecting deep mantle dynamics including partial melting.Early experimental studies on carbonated eclogites mostly focused on the fate of carbonated oceanic eclogites under the subduction zone geotherm.In recent years,partial melting experiments of carbonated eclogite under the upper mantle conditions reveals the potential contribution of carbonated eclogite component to the mantle source of intraplate alkaline basalts.In this paper,we briefly review the partial melting experiments of carbonated eclogites under the conditions of upper mantle temperature and pressure,and together with some case studies on natural samples,we show that partial melts of carbonated eclogite can not only potential mantle metasomatic agents,but also may be important components in the source of intraplate alkaline basalt,and their interaction with mantle peridotite or mixing with peridotite melt can explain the compositional variation of intraplate alkaline basalts.
作者
徐荣
刘勇胜
张艳飞
邹宗琪
张军波
XU Rong;LIU YongSheng;ZHANG YanFei;ZOU ZongQi;ZHANG JunBo(State Key Laboratory of Ore Deposit Geochemistry,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;State Key Laboratory of Geological Processes and Mineral Resources,School of Earth Sciences,China University of Geosciences,Wuhan 430074,China;State Key Laboratory of Isotope Geochemistry,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China)
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2022年第12期3771-3784,共14页
Acta Petrologica Sinica
基金
国家重点研发计划项目(2019YFA0708400)
国家自然科学基金项目(41903035)联合资助.
