Project title: Hydrothermal and metamorphic mineral growth in the Central African Copperbelt
Researcher: Dr Anna Bidgood
Kyanite-bearing mineral assemblages and veins are observed throughout the Central African Copperbelt (CACB). Pressure and temperature estimates from the Congolese Copperbelt, in the region surrounding the kyanite-bearing rocks, indicate that this region was only buried to depths that would result in low pressure and temperature conditions (<400 °C, < 10 km depth), conflicting with the traditionally high pressure and temperature hypothesis for the formation of kyanite. Kyanite also occurs in veins and in metamorphic mineral assemblages, associated with intensely altered regions adjacent to basement domes in the Zambian Copperbelt, a region of high metamorphic grade. The unusual occurrence and distribution of kyanite in the Central African Copperbelt and the potential association with metal sulphides and saline fluids, raises questions as to the genesis of kyanite-bearing deposits and has implications for the tectonic history of the CACB as well as traditional mineral thermodynamics. Saline fluids are instrumental in forming mineral deposits in the Earth’s crust, such as those in the Central African Copperbelt (CACB) of the Democratic Republic of Congo and Zambia which represent the world’s primary source of cobalt, critical for the batteries needed for helping to decarbonize our societies.
Hypothesis: Kyanite-bearing lithologies are spatially and temporally linked to mineralisation in the CACB and are influenced by the presence of saline fluids which influence the conditions of formation.
- To understand the petrogenesis of kyanite-bearing lithologies and their associated fluid chemistry in the Central African Copperbelt
- To study the association of kyanite-bearing lithologies with metal sulphides and understand the implications for metal transport in saline fluids.
- To undertake mineralogical, geochemical and isotopic analysis of a range of accessory minerals (principally kyanite) from locations across the Central African Copperbelt
- Carefully assess links between fluid and alteration chemistry and kyanite mineral formation
- Carry out targeted and detailed geochemical analysis of kyanite and create geochemical and mineral stability models that can be used to inform ore depositional processes
This project will focus on the mineral associations, geochemistry and fluid inclusion assemblage of kyanite in lithologies across the CACB. The principal focus of this study is the Menda prospect in the Congolese Copperbelt. Samples from Kansanshi in the Zambian Copperbelt will also be studied, with potential for samples from Lumwana, Sentinel, Enterprise and Nkana deposits.