Depositional systems and geochemistry of the kavirondian sedimentary rocks in the late archaeannzega greenstone belt, Tanzania

This study deals with unraveling the depositional and tectonic evolution of the Kavirondian sedimentary rocks of the Nzega Greenstone Belt (NGB), Tanzania. This study uses a number of research methods, which includes; i) Detailed geological mapping ii) Petrographical and geochemical investigations of the collected rock samples and iii) Inspections of diamond drill-cores against gold assay results to understand gold mineralization processes in Kavirondian sedimentary rocks. The Kavirondian sedimentary rocks in the NGB define a fault controlled basin with intrabasinal topography probably associated with intrabasinal faulting, unconformablyoverlie Nyanzian rocks. Based on lithofacies association, stratigraphy and palaeocurrent data, five end-member depositional systems have been identified, namely; the Chomachankola System, the Usenge conglomerate System, the Hop Hill sandstone System, the Shoga sandstone System, and the Mapagale sandstone- dominated System. The Chomachankola System is interpreted as a canyon-filled high energy proximal System. Petrography and geochemical studies reveals a proximal heterogeneous source rocks for the conglomerate rocks, ranging from mafic to felsic rocks and chemical sedimentary rocks (BIF/chert), and a granitic source rocks for the sandstones, and deposition on a passive continental margin. Furthermore, the study indicates a structural-controlled epigenetic gold mineralization within strongly chlorite- sericite and haematite-altered sandstone and conglomerate sequences at Resolute’sKavsav Gold Project. The study recommends further drilling in the area to determine the size of the deposit