Late Proterozoic and Early Paleozoic Metasediment-hosted Tungsten Mineralization in Central Namibia: Recent Advances in Exploration and Research (dc8cb2e8-3c7f-472c-b963-635a8420490b)
- Organization:
- Canadian Institute of Mining, Metallurgy and Petroleum
- Pages:
- 12
- File Size:
- 1105 KB
- Publication Date:
- Jan 1, 1994
Abstract
Mineral exploration and research has led to the identification of four types of tungsten mineralization in the NE-trending, Iargelyensialic, inland branch of the late Proterozoic/early Paleozoic Pan-African Damara Orogen. The mineralization (mainly scheelite) occurs in a terrane (the Central Zone) that is characterized by multiple deformation, greenschist/amphibolite-facies metamorphism and numerous peraluminous S-type granitic and pegrnatitic intrusions. The four major types of scheelite mineralization are (in ascending stratigraphic order of host rock): (1) thin (5 cm to 2 meter) quartz+plagioclase+diopside ± scapolite calc-silicate granofels with fmely disseminated scheelite (scheelite-bearing granofels; SBG) developed as discontinuous intercalations within the calc-silicate rocks of the Khan, Spes Bona, Oberwasser and Kuiseb Formations (Nosib and Swakop Groups); (2) gamet+pyroxene± vesuvianite+scheelite ± fluorite replacement skarns hosted by Okawayo, Karibib and lower Kuiseb Formation marbles in the aureoles of late tectonic, unrnineralized leucogranites; (3) metaturbidite-hosted scheelite- (and possibly wolframite-) bearing tourmalinites, both stratiform and crosscutting, in the Kuiseb Formation located in the 'cleavage fronts' of late tectonic granitoids; (4) scheelite-bearing vesuvianite+quartz+garnet skarnoid rocks (several hundred meters in length) in the calcareous metaturbidites of the upper Kuiseb Formation. These scheelite occurrences were discovered by the follow-up of a large number of tungsten anomalies located during a regional stream sediment sampling program. Detailed mapping, ultra-violet surveys and rock sampling proved to be the most effective surface exploration techniques for locating mineralization; soil sampling and geophysics were of almost no use. The largest, continuous scheelite-bearing skarn of economic interest, Otjua, has a drill-indicated reserve of 250 000 tonnes at 0.53 wt5 WO3 and 8 wt% CaF2•
Citation
APA: (1994) Late Proterozoic and Early Paleozoic Metasediment-hosted Tungsten Mineralization in Central Namibia: Recent Advances in Exploration and Research (dc8cb2e8-3c7f-472c-b963-635a8420490b)
MLA: Late Proterozoic and Early Paleozoic Metasediment-hosted Tungsten Mineralization in Central Namibia: Recent Advances in Exploration and Research (dc8cb2e8-3c7f-472c-b963-635a8420490b). Canadian Institute of Mining, Metallurgy and Petroleum, 1994.