A review of the geological settings,ages and economic potentials of carbonatites in the Democratic Republic of Congo

Abstract

Carbonatite occurrences are reported in Lueshe, Kirumba, Bingo and Mombadio in the Democratic Republic of Congo (DRC), within the western branch of the East African Rift System (EARS). These rocks intrude Precambrian rocks, which are mainly quartzites and mica schists. Lateritic profiles from Lueshe and Bingo are ore-bearing minerals enriched in Nb₂O₅ and phosphate minerals. The Lueshe and Bingo exploitable quantities are estimated to be 30 Mt at a grade of 1.34% Nb₂O₅ and 7 Mt at a grade of 2.86% Nb₂O₅, respectively. These carbonatites were explored and exploited by some mining companies in the 1970s and 2000s. They show geological and geochemical similarities to other exploitable carbonatites in the EARS, including Mrima Hill in Kenya, Panda Hill in Tanzania and the world-class Araxá and Catalão carbonatites in Brazil. The Lueshe and Kirumba alkaline massifs dates, determined using the whole-rock Rb–Sr method, are respectively 822 ± 120 and 803 ± 22 Ma and are intimately linked to the Rodinia Supercontinent breakup. These dates are analogous to other regional carbonatite dates like the Matongo carbonatite in Burundi. However, further geological, petrological and geochemical studies on carbonatite complexes are essential in DRC. Most importantly, the economic potentials of Kirumba and Mombadio should be evaluated. Simultaneously, the dates of the Bingo and Mombadio carbonatites are crucial for the elucidation of their geodynamic settings.