A Himalayan-Scale Orogen in the Central African Copperbelt and the Formation of a World-Class Metal Province.

Tobermory Mackay-Champion

The Central African Copperbelt (CACB) of Zambia and the Democratic Republic of the Congo is the world’s largest sediment-hosted copper-cobalt province. It comprises Tonian–Ediacaran sedimentary rocks of the Katangan Basin and Ediacaran–Cambrian metamorphic and intrusive rocks formed during the assembly of Gondwana. The age distribution of metal deposits within the CACB peaks during the orogeny, indicating a significant orogenic control on mineralization. This study synthesizes existing structural, petrological, geochronological, and geophysical data to propose a new geodynamic model that reinterprets the CACB as a Himalayan-scale, continental-collision orogenic system. Its tectonic evolution is characteristic of a typical Wilson Cycle: continental rifting and ocean basin formation (≤ 880--650 Ma); oceanic subduction and pre-collisional metamorphism (≤ 650 Ma); continent-continent collision (≤ 570 Ma), leading to significant crustal thickening with burial depths reaching up to 45 km (~530 Ma); and late-stage thrusting and magmatism (≤ 510 Ma). The new model indicates that the CACB benefitted from two principal metal sources: metals derived from basement erosion, and metals introduced by magmatism during and after continent–continent collision, which is newly identified in this study. The next generation of metal deposits in the CACB will be found by locating outcropping or shallow subsurface magmatic intrusions.