土耳其蛇绿岩地幔橄榄岩研究进展和展望
作者:
作者单位:

南京大学地球科学与工程学院

基金项目:

国家重点研发计划(编号 2023YFF0804402)、国家自然科学基金(编号 42330306,42272068,42302080)、江苏省卓越博士后计划(编号 2022ZB12)、中央高校基本业务费(编号 2024300422,2023300168)、地质过程与矿产资源国家重点实验室科技部专项经费资助(GPMR202435)


Research progress and prospect of the ophiolite peridotite in Turkey
Author:
Affiliation:

1.School of Earth Sciences and Engineering, Nanjing University;2.Nanjing University

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    摘要:

    土耳其蛇绿岩分布于多个构造单元,如北Anatolide带、Tauride蛇绿岩带和南部蛇绿岩带,其代表了特提斯洋岩石圈的残余,反映了复杂的板块构造演化历史。土耳其蛇绿岩中的地幔橄榄岩主要以方辉橄榄岩为主、局部发育有少量的纯橄岩和二辉橄榄岩,且普遍遭受了不同程度的蛇纹石化的改造。地幔橄榄岩的全岩以及矿物学特征保存了与其成因及形成构造背景相关的重要信息。土耳其蛇绿岩中的地幔橄榄岩具有显著的稀土元素和微量元素分布特征,反映了不同程度的部分熔融和后期岩浆作用的影响。二辉橄榄岩显示轻稀土亏损的左倾模式,而方辉橄榄岩和纯橄岩则呈现“U”型或“V”型稀土分布,表明其遭受了来源于俯冲带富轻稀土元素的熔/流体的改造作用。铬铁矿的研究是土耳其蛇绿岩中的重要领域,尤其是豆荚状铬铁矿的分布和成因特征,为我国铬铁矿的找矿工作提供了宝贵的指导。研究表明,铬铁矿的形成、是地幔源区部分熔融,熔体-岩石反应以及岩浆晚期分离结晶综合影响,同时有来自深部地幔物质的贡献。在超俯冲带背景下的壳幔过渡带以及上地幔顶部是铬铁矿的赋存关键区域。中等亏损的方辉橄榄岩和大规模的纯橄岩是重要的找矿标志。此外,含矿岩体的剥蚀程度直接影响铬铁矿体的保存和暴露情况,是找矿过程中需重点关注的因素。总结而言,土耳其蛇绿岩的研究不仅深化了对地幔动力学和板块构造过程的理解,也为铬铁矿的勘探提供了科学依据。通过结合地幔橄榄岩的岩石学和地球化学特征,聚焦有利构造环境、大规模纯橄岩发育区域以及适度剥蚀的含矿岩体,未来的铬铁矿找矿工作有望显著提升效率并取得更丰硕的成果。

    Abstract:

    Turkey ophiolites are distributed across several tectonic units, such as the Northern Anatolian Belt, the Tauride Ophiolite Belt, and the Southern Ophiolite Belt. These ophiolites represent remnants of the Tethyan oceanic lithosphere and reflect the complex tectonic evolution of the region. Studies show that the mantle peridotites within these ophiolites, including harzburgite, dunite, and lherzolite, are extensively serpentinized and exhibit mineralogical and geochemical affinities with peridotites formed in abyssal and forearc settings. The mineralogical characteristics of mantle peridotites, such as the chemical compositions of olivine, orthopyroxene, clinopyroxene, and the Cr# and Mg# values of chromite, provide crucial insights into their melting history and tectonic origin. Geochemical analyses further reveal that mantle peridotites in Turkish ophiolites exhibit significant variations in rare earth element (REE) and trace element distributions, indicating varying degrees of partial melting and subsequent melt-rock interactions. Lherzolites display a left-leaning REE pattern with light REE depletion, while harzburgites and dunites show “U”- or “V”-shaped REE patterns resulting from interaction with LREE-enriched melts/fluids in suprasubduction zone settings. Chromitite research is a key focus within Turkey ophiolites, especially the distribution and genesis of podiform chromitites, which provide valuable guidance for chromitite exploration. Studies indicate that chromitite formation is influenced by a combination of mantle partial melting, melt-rock interaction, and magmatic fractional crystallization, with contributions from deep mantle materials. The mantle-crust transition zone and the upper part of the mantle in supra-subduction zone settings are identified as critical areas for chromitite formation. Moderately depleted peridotites, especially harzburgites associated with dunites, are important exploration indicators, while large-scale dunites of boninitic affinities provide favorable spatial conditions for chromitite enrichment. Additionally, the preservation and exposure of ore-bearing bodies, closely tied to the degree of erosion, are crucial factors to consider during exploration. In conclusion, the study of Turkish ophiolites not only deepens the understanding of mantle dynamics and plate tectonics but also provides scientific guidance for chromitite exploration. By integrating the petrological and geochemical characteristics of mantle peridotites, focusing on favorable tectonic settings, large-scale dunite regions, and moderately eroded ore-bearing bodies, future chromitite exploration efforts are expected to achieve greater efficiency and yield more significant results.

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  • 收稿日期:2025-01-20
  • 最后修改日期:2025-03-29
  • 录用日期:2025-04-07