Metallogenic Analysis of Tungsten, Molybdenum, and Tin Deposits in the Context of the Current Geodynamic Concepts

The paper discusses aspects of metallogenic classification of W, Sn, and Mo deposits and considers their affinities corresponding to different geodynamic settings. Most large W deposits correspond to the tungsten-polymetallic and tungsten-molybdenum metallogenic types and were formed in post-subduction (post-collisional and transform margin) settings. Tin-polymetallic deposits could be formed in post-subduction (post-collisional) and within-plate settings as well as in subduction settings, the latter, however, associated with steep-dipping subduction and asthenosphere mantle upwelling yet at the subduction stage. Consistently, this made the geodynamic regime similar to that in post-subduction (post-collisional) setting. Large W–Sn deposits more distinctly formed in post-subduction (post-collisional) settings. Rare metal-tin-tungsten, Sn-polymetallic, and W-Mo deposits formed also in the transitional (to within-plate) post-collisional and actual within-plate settings. Molybdenum deposits formed in subduction (Cu–Mo–Au deposits), post-collisional (Mo–W deposits), transitional, and within-plate (Mo, Mo–Au, and Mo–U deposits) settings. In the areas of polycyclic tectonic development, which included within-plate regime, polychronous W, Sn, and Mo deposits could be formed. Two evolutionary trends (“series”) of metallogenically-related W, Sn, and Mo deposits can be distinguished: (1) a “series” of molybdenum-free deposits (W-polymetallic, W–Sn, Sn-polymetallic and rare metal–Sn–W deposits), and (2) a “series” of deposits with significant Mo mineralization (Cu–Mo–Au, W–Mo–Cu–Au, Mo–W, Mo, and Mo–U deposits), with the respective differences of magmatic sources of productive intrusions. These evolutional trends of deposits are spatially separated in different metallogenic belts and segments, which correspond to belts/segments of ilmenite- and magnetite-series granitoids, respectively. In this regard, molybdenum-free deposits formed mostly in turbidite terranes of the accretion prism, whereas deposits with significant Mo mineralization formed in cratonic terranes with thick continental (cratonic granitic-gneissic) crust. W, Sn and Mo deposits are associated dominantly with magmatic complexes of mixed mantle-crust affinity including “hybrid” granitoid complexes, monzonitoid complexes of shoshonitic series, and anorogenic (A-type) granitic complexes. Melting of the Earth’s crust with various thickness and compositions could have been induced by deep-seated sources both in the oxidized metasomatized lithospheric mantle and in the reduced asthenospheric mantle, with their respective redox differences affecting the redox-potential of the final hybrid magmas.