Geochronology, Petrogeochemical Characteristics, Tectonic Setting of the Leucogranites (～1.0 Ga) in Central Africa and Its Relationship with Mineralization

A large number of mineral resources related to granite−pegmatite system that are found in the traditional Mesoproterozoic Kibaran belt in Central Africa, especially characterized by the distinctive mineralization of rare metals (Nb−Ta−Li), tungsten, tin and gold. The metallogenic events can be associated with the process of Rodinia amalgamation. Most of these mineral occurrences are linked to the early Neoproterozoic G4 leucogranitic intrusions, also termed “tin (−bearing) granites”. G4 granites have been extensively scrutinised because they are considered as the parental rocks to the ore mineralization in the region. The field identification criteria, timing, geochemical characteristics for G4 granites in different parts of Kibaran belt, however, have been shown to vary in previous studies. As a result, the type of rock, the petrogenesis of these parental granites and the geodynamic context is still a matter of debate. Combined with the disparate nature of datasets in the literature (e.g. field outcrops, petrography, geochronology, geochemistry and isotopes), the results show that the derivation of G4 granite is consistent with a meta−pelitic source, and these leucocratic granites could be considered more like anatectic migmatites rather than actual highly fractionated granites formed by fractionation out of large magma chambers. It has been largely established via the research of diagenetic and metallogenic processes that the protracted differentiation of G4 granites is the primary driver of diverse mineralization in the Kibaran belt. It’s hypothesized that the G4 granite was probably emplaced in the syncollisional to post−collisional stage of Kibaran orogeny when considering the regional tectonic background.