Contrasting granites associated with W, Sn, and Be mineralization in the Xuebaoding and Pingwu areas, Sichuan Province, SW China

• Published in: Ore geology reviews Vol. 166; p. 105933
• Main Authors: Zhu, Xinxiang, Raschke, Markus B., Liu, Yan
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2024
• Subjects: Highly fractionated granite; S-type granite; W–Sn–Be mineralization; Highly fractionated granite; S-type granite; W–Sn–Be mineralization
• ISSN: 0169-1368; 1872-7360
• DOI: 10.1016/j.oregeorev.2024.105933

The granites from Pingwu area are found to be S-type, aged 211.4 ± 0.65 to 229.8 ± 0.58 Ma, with high A/CNK values (>1.07). From comparison with the Xuebaoding albite granites, this suggests a cogenetic magmatic origin, yet different magmatic evolution with a lower degree of internal fractionation of the Pingwu system. The tungsten, tin, and beryllium segregations in Xuebaoding and Pingwu area likely further controlled by protolith, melting mechanism and ore-controlling structures. [Display omitted] •Granites from Pingwu are S-type, of 211.4 ± 0.65 to 229.8 ± 0.58 Ma age.•The granites from Xuebaoding and Pingwu area are suggested of a cogenetic magmatic origin.•Factors as protolith, melting mechanism, fractionation, etc control the W-Sn-Be segregations. Rare metals (e.g., tungsten, tin, or beryllium) are critical strategic elements mainly hosted by magmatic-hydrothermal ore deposits associated with granitic intrusions. The simultaneous occurrence of W, Sn, and Be is unusual, and the underlying processes leading to the formation of corresponding ore deposits is not yet understood. In that regard, the Xuebaoding W-Sn-Be deposit in the Songpan-Garzê Orogenic Belt of western China stands out with its exceptionally high Be content with only weak alteration. While the Xuebaoding deposit has been the subject of much previous petrographic, geochronological, mineralogical, and ore-forming fluid investigations, few studies have yet addressed the regional granitoid rocks around the deposit and their potential association with the Xuebaoding system. Here, a contrasting lithologic, geochemical, chronological, and Sr–Nd–Pb isotope analyses of granites from neighboring intrusions with only W mineralization near Pingwu is performed. The Pingwu granites are found to be S-type, of 211.4 ± 0.7 to 229.8 ± 0.6 Ma age, with high A/CNK values (>1.07), and Sr–Nd–Pb isotope values of 87Sr/86Sr(i) = 0.70589–0.71486, εNd(t) = −3.49 to −9.51, 206Pb/204Pb = 17.9378–18.3996, 207Pb/204Pb = 15.5693–15.6836, and 208Pb/204Pb = 38.1382–38.7390. In addition, these granites are low in W (0.06–4.1 ppm), Sn (1.0–7.3 ppm) and Be (1.6–8.6 ppm). A comparison with the Xuebaoding granites suggests a cogenetic origin, but a lower degree of fractionation in the Pingwu system. The different petrogenesis of the W occurrences near Pingwu with respect to the W–Sn–Be deposit are likely due to a combination of protolith, melting mechanism, and ore-controlling structures. The work highlights the unusual conditions necessary for the spatial or temporal coexistence of W, Sn, and Be mineralization within the same deposit as represented by only few deposits worldwide.