A review and outlook on Archean greenstone belt-hosted chromite deposits

查看详情 浏览次数:1
单位[Wang Jiawei] China Univ Geosci, Sch Earth Sci & Resources, Beijing 100083, Peoples R China; [Wang Jiawei] CAGS, Inst Mineral Resources, MNR Key Lab Metallogeny & Mineral Assessment, Beijing 100037, Peoples R China; [Cai Pengjie; Lian Dongyang; Yang Jingsui] Nanjing Univ, Sch Earth Sci & Engn, State Key Lab Mineral Deposits Res, Nanjing 210023, Jiangsu, Peoples R China; [Szilas, Kristoffer] Univ Copenhagen, Dept Geosci & Nat Resource Management, DK-1350 Copenhagen, Denmark; [Yang Jingsui] Chinese Acad Geol Sci, Inst Geol, Ctr Adv Res Mantle CARMA, Key Lab Deep Earth Dynam,Minist Nat Resources, Beijing 100037, Peoples R China
来源ACTA PETROLOGICA SINICA
出版年2023
期号12
摘要
Archean greenstone belt-hosted chromite deposits are an important source of chromium and are also significant for understanding the characteristics and tectonic settings of the early Earth. Occurrences of chromitite have formed for a long time and have generally experienced metamorphism, deformation and fluid alteration. When compared with podiform chromitite and stratiform chromitite in more recent settings, there is a poor understanding and lack of systematic in-depth research for the Archean examples, especially the metallogenic and magmatic process. The main geological host rocks of typical Archean chromitites in Greenland, India, Australia, Canada, and Zimbabwe are described in this paper. Such chromitite deposits mainly formed in the Paleo- to Neoarchean (3.3 similar to 2.7Ga), and these ore bodies are either lentiform, stratiform or irregular and are generally hosted within serpentinized dunite. Therefore, it cannot be simply attributed to stratiform chromitite or podiform chromitite. The chrome-spinel of massive chromitite is characterized by having high Cr-# (>60) values and medium-high Mg-# value (21 similar to 93), which are negatively correlated. Such chrome-spinel contents are indicative of a parental magma of komatiitic affinity derived from high degrees of partial melting of a deep mantle reservoir, and subsequent modification by crustal contamination. Archean [JP2]chromite deposits were emplaced within open magma chambers, where the primary parental magma mixed with continuously replenished komatiitic magma. This mixture underwent gravitational differentiation and convective layering within the magma chamber, leading to the formation of cumulate chromitite ore bodies.
同主题文献

    @ 2023 版权所有 中国地质图书馆 (中国地质调查局地学文献中心)

    京ICP备 05064591号 京公网安备11010802017129号

    建议浏览器: 火狐、谷歌、微软 Edge、不支持 IE