深海橄榄岩蛇纹石化温度条件的氧同位素约束  

Oxygen isotope constraint on the temperature condition of serpentinization in abyssal peridotites

作　　者：许绪成 余星 胡航[1,2] 何虎 余娅娜[1] XU Xucheng;YU Xing;HU Hang;HE Hu;YU Ya na(Key Laboratory of Submarine Geosciences,Second Institute of Oceanography,MNR,Hangzhou 310012,China;Ocean College,Zhejiang University,Zhoushan 316021,China)

机构地区：[1]自然资源部海底科学重点实验室,自然资源部第二海洋研究所,浙江杭州310012 [2]浙江大学海洋学院,浙江舟山316021

出　　处：《海洋学研究》2024年第2期104-112,共9页Journal of Marine Sciences

基　　金：国家重点研发计划项目(2021YFF0501301);国家自然科学基金项目(42172231,41872242);中央级公益性科研院所基本科研业务费专项资金资助项目(QNRC2202)。

摘　　要：深海橄榄岩在海底洋中脊、俯冲带和大陆边缘等构造环境中广泛分布,并普遍经历后期蚀变,其中蛇纹石化作用是最主要的蚀变类型。蛇纹石化是指橄榄岩中富镁铁矿物,如橄榄石和辉石,被蛇纹石、磁铁矿、水镁石等一系列次生矿物所取代的化学过程。蛇纹石化反应条件与热液循环、成矿物质迁移等具有密切的联系,对指示热液成矿作用具有重要意义。传统的岩石矿物学、地球化学方法在反映蛇纹石化条件时具有多解性和不确定性,不同矿物或不同化学指标可能指示不同的结果。氧同位素在自然界普遍存在,氧同位素示踪法具有适用范围广、容易比对、支持原位微区分析等优点,可以清晰地反映矿物或岩石-流体体系的反应条件和过程。该文主要综述了氧同位素测温法的原理、深海橄榄岩蛇纹石化过程、氧同位素测温法在深海橄榄岩蛇纹石化过程中的应用案例、蛇纹石氧同位素组成变化的影响因素以及氧同位素测温法的优势和局限性等问题,为后续更深入地了解深海橄榄岩蛇纹石化过程提供参考。Abyssal peridotite is widely distributed in tectonic environments such as mid-ocean ridges,subduction zones,and continental margins,and typically undergoes subsequent alterations,among which serpentinization is the most significant type.Serpentinization refers to the chemical process wherein ferromagnesium-rich minerals in peridotite,such as olivine and pyroxene,are replaced by a series of secondary minerals like serpentine,magnetite,and brucite.The conditions of serpentinization are closely linked with hydrothermal circulation and the migration of mineral-forming substances,bearing significant implications for indicating hydrothermal mineralization.Traditional methods of petrology and geochemistry exhibit polysemic interpretations and uncertainties when reflecting serpentinization conditions,with different minerals or chemical indicators possibly suggesting different outcomes.Oxygen isotopes are ubiquitous in nature and the oxygen isotope tracing method,due to its wide applicability,ease of comparison,and support for in-situ micro-zone analysis,can clearly reflect the reaction conditions and processes of the mineral or rock-fluid system.This study primarily provides an overview of the principles of oxygen isotope thermometry,the process of abyssal peridotite serpentinization,application cases of oxygen isotope thermometry in the serpentinization of abyssal peridotite,factors influencing the oxygen isotope compositions of serpentinites,as well as the advantages and limitations of oxygen isotope thermometry.It aims to offer a reference for a more profound understanding of the serpentinization process of abyssal peridotite.

关 键 词：深海橄榄岩 蛇纹石化 水岩反应 氧同位素 温度 

分 类 号：P597[天文地球—地球化学] P588.12[天文地球—地质学]