Structural control on the Sn-Ta-Nb mineralisation and geochemistry of the pegmatites of Gitarama and Gatumba areas (Rwanda), Karagwe–Ankole Belt

Autor: Ivan Ludovic Raoelison, G. O. Adeyemi, Anthony T. Bolarinwa, Claude Nambaje, Jean de Dieu Ndikumana, Parfait Mutiyamuogo Mupenge
Rok vydání: 2021
Předmět:
Zdroj: Arabian Journal of Geosciences. 14
ISSN: 1866-7538
1866-7511
DOI: 10.1007/s12517-021-09033-8
Popis: This study used integrated geochemical and structural approaches to investigate the Nb–Ta-Sn mineralisation from Gitarama and Gatumba areas in the south-western Rwanda, Karagwe–Ankole Belt (KAB). Pegmatite and quartz veins were targeted in the present study. The pegmatite veins were observed to trend roughly to the north, whilst the quartz veins orient to the north-east and north-west. The crenulation lineation (L2) on the host graphite rich-schist, and structural measurements coupled with the geochemical analysis of pegmatites showed that the pegmatites are tectonically emplaced, syn to post-collisional, with metaluminous to peraluminous characteristics. The analysed pegmatites showed the enrichment of Nb (3.9–517 ppm), Ta (1.3–268 ppm), Cs (2.6–24.7 ppm), Sn (24–1505 ppm) and Rb (181–605 ppm), with indices of profitable mineralisation. The pegmatites are zoned from Gitarama to Gatumba area, where biotite, biotite-muscovite, muscovite and Nb–Ta-Sn mineralised pegmatites were encountered respectively. This zoning is mostly due to the fractionated crystallisation of melt during the upward migration from its source region. Combined evidence from structural features and geochemical results indicates that potential Nb–Ta-Sn mineralisation is structurally controlled.
Databáze: OpenAIRE
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