The world-class Nanling metallogenic belt (Jiangxi, China): W and Sn deposition at 160 Ma followed by 30 m.y. of hydrothermal metal redistribution
Résumé
The W-Sn Maoping deposit and related W-Sn deposits from the world-class Nanling Range in Southeast Chinaformed at ca. 160 Ma and experienced several phases of metal addition and metal redistribution between 160and 130 Ma. Isotopic dating of ore mineral (wolframite) of Maoping demonstrates that W was deposited first,during a hydrothermal event at ca. 160 Ma. Successive fluid episodes, at ca. 156 Ma (Mo and Sn-rich fluid) and152 Ma (REE-rich fluid), resulted in the formation of REE- and Fe-Cu-Zn-sulfide minerals. A last fluid eventoccurring at ca. 130 Ma was responsible for the deposition of Zr-REE-Nb-Ta minerals that are attributed tomagmatic fluids derived from unexposed magmatic bodies. The three episodes of fluid circulation post-dating Wdeposition resulted in partial to complete resetting of the isotopic systems (mica, wolframite, xenotime), whichare conventionally used for dating such deposits. We show that W and Sn mineralization in the Nanling Rangeformed during a unique fluid event at ca. 160 Ma. Later fluid episodes redistributed the previously depositedmetals and sequentially introduced additional metals, including Mo-Sn, Fe-Cu-Zn, and Zr-REE-Nb-Ta. Directdating of paragenetically well-constrained minerals is therefore critical for determining the age and the durationof mineralizing processes and for characterizing the fluid evolution of magmatic-hydrothermal systems, as exemplifiedin the Nanling Range.
Domaines
GéochimieOrigine | Fichiers produits par l'(les) auteur(s) |
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