Several tungsten deposits, from which ca. 1,800 metric tons (t) of concentrate at 65.3 percent W03 was produced, occur in the Okiep copper district, South Africa, which is part of a high-temperature, low-pressure granulite terrane (M 2 ; 750 degrees -850 degrees , 5-7 kbars). The 1.2 to 1.0 Ga high-grade metamorphism of Proterozoic supracrustal and older intrusive rocks is polymetamorphic and was accompanied by crustal melting resulting in formation of several early to postorogenic granitoid suites. The W-Mo deposits are spatially and genetically associated with the 1.1 Ga Concordia granite, a silica-rich (70-76 wt %), peraluminous leucogranite with subalkaline monzonitic magma characteristics. More fractionated cogenetic intrusions are interpreted as separated residual granitic liquids. They are enriched in large ion lithophile (K 2 O, Rb) and some high field strength (W, Nb, etc.) elements. Mineralized pegmatites, replacement orebodies (strongly silicified granitic rocks), and exo- and endogranitic veins are distinguished. Ferberite and minor scheelite are associated with Mo, Cu, and Bi sulfides and U-Th, Nb, REE silicates, oxides, and phosphates. Metapelites (Wolfram schist) hosting S 2 subparallel exogranitic veins are characterized by M 2 upper amphibolite-lower granulite facies assemblages (biotite-sillimanite + or - garnet, + or - cordierite plus quartz, alkali feldspar, and plagioclase). Schistose host rocks were derived from normal clastic sedimentary material, slightly peraluminous lithologies probably from more pelitic kaolinite-rich precursors. The facts that late to postorogenic granites and the W-Mo deposits are deformed, metamorphic ore textures (e.g., garnet coronas around ore minerals) are preserved, and ore deposit, specific hydrothermal low- temperature alteration is absent, suggest that the second M 3 late-Kibaran metamorphic overprint postdated mineralization. Oxygen isotope temperatures of ca. 600 degrees to 660 degrees C for coexisting garnet and quartz from mineralized veins and host rocks indicate that high-grade conditions were again reached during this late Kibaran overprint. Retrograde greenschist facies metamorphism is of Pan-African age (ca. 560-590 Ma) and is unrelated to mineralizing processes. The W-Mo deposits are interpreted as metamorphosed, deep-seated granitic ore deposits occurring in a polymetamorphic high-grade terrane. Two high-grade events of Kibaran age (M 2 and M 3 ) and a low-grade event of Pan-African age (M 4 ) are distinguished.

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