Copper/Cobalt strata-bound systems; A Basin Analysis approach to the tectonostratigraphic evolution of the Central African Katangan basin of Zambia and its strata-bound copper deposits.

Copper/Cobalt strata-bound systems; A Basin Analysis approach to the tectonostratigraphic evolution of the Central African Katangan basin of Zambia and its strata-bound copper deposits.

What are the geodynamic, tectonic and stratigraphic processes of Central African Neoproterozoic sedimentary basins responsible for continental (Gondwana) crustal growth? And how did they influence the mobilisation, transportation, concentration and precipitation of  copper and cobalt in the Central African Copper/Cobalt province?

The geodynamic and tectono-stratigraphic development of Western Gondwana, in both Africa and Brazil, involves the development and accretion of a series of terranes recorded in the stratigraphy and structure of Neoproterozoic basins. Key to understanding this process of Supercontinent growth is the subsidence and deformational history of these basins as indicators of the precollisional history and later accretionary processes that constructed Gondwana. These same basins record the Neoproterozoic glaciogenic periods and, in the case of the Katangan basin of Central Africa, became the depository of the world’s largest strata-bound copper/cobalt deposits.

This project will take a first principle and integrated approach to the analysis of the Neoproterozoic Katangan basin, with the intent of defining the processes of basin formation and subsequent deformation resulting in the growth of Gondwana. The genesis of major copper deposits is an integral part of this process, adding significant constraints on the thermal, fluid and geochemical evolution of the basin. Building on the well-known lithostratigraphic framework, a regional sequence stratigraphic model will be built, paleogeography mapped and structural restorations used to build an evolutionary model of the basin. Individual subsidence profiles will be created and back-stripped to establish a subsidence history. This will be back-stripped with the help of thermochronological data to understand the subsidence driving mechanism and quantify heat flow through time. Integrating this with the magmatic and metamorphic history of the basin will place constraints on the timing and mechanism of fluid flow. From this dynamic base a model of Neoproterozoic basin evolution and deformation and large scale copper mineralisation will be developed. Such a dynamic basin analysis will be new to the Katangan basin and the issue of Neoproterozoic basin formation and deformation in Central Africa generally. It will be challenging due to poor chronological control, but will undoubtedly provide new perspectives to the process of Neoproterozoic crustal growth, basin formation, tectonics and metallogenesis. The underpinning geoscience work will be largely core based stratigraphic analysis and mine and field section construction and restoration. In addition to these basic geological sources, funding will be required for zircon U/Pb provenance studies, zircon, apatite and fluid inclusion thermochronometry and palaeontology will be required to support the dynamic basin subsidence analysis.

The expected outcome being a regional basin analysis integrated with the fluid dynamics of copper mobilisation, concentration and deposition. A budget of approximately £35,000 spread over the four years will be required for the analytical work associated with this project, part of which will be carried out by the student and part by the British Geological Survey. This work will be augmented by the supporting mining company FQM.

Industrial partner motivation

The multi-decade energy transition to a low carbon world is increasing the demand for minerals key to electricity transmission and storage. This in turn is generating a renewed search for copper and cobalt. Historically copper and cobalt have been discovered through surface detection. To satisfy the growing demand, increasingly deep, ‘under cover’ exploration will be required that will draw on the predictive capability of mineral exploration. The industry is well aware of this context and is expanding its exploration activity, process and knowledge base. This CASE award will incorporate the principles and tools of petroleum system exploration and basin analysis and extend and modify it to include the search for copper and cobalt.

The student will be supported by First Quantum Minerals (FQM), Central Africa’s largest copper producer. He/she will have access to the Kalalushi core store that harbours over X,000 cores, some over 2 km in depth, from which to develop a regional data set. FQM has agreed to support three mine and field visits to Zambia during the four years of the project. These will include core logging, mine visits and selected field traverses with FQM support.

Aims of the Project

To define the dynamic stratigraphy, subsidence history, deformation and thermal evolution of the Katangan basin of Central Africa and develop a model for the genesis of its major copper deposits.

Methods to be used

Three different but complimentary methods will be integrated to define the development of the Katangan basin of Central Africa and its fugitive mineral carrying systems:

1) Dynamic stratigraphy, palaeontology, paleogeographic and subsidence analysis developed from the logging of a regional set of diamond drill (DD) cores from throughout the basin.

2) Tectonic analysis of the evolution of the basin largely based on core correlation, selected mine sections and selected field traverses.

3) Thermal history analysis including low grade metamorphism, fission track and potentially fluid inclusion thermochronometry to integrate fluid flow with the tectonic history and stratigraphic architecture.

Specialised skills required by the student

1) Sequence stratigraphic analysis and depositional system interpretation.

2) Structural restorations of deformed sections.

3) Subsidence history and back-stripping of Neoproterozoic stratigraphy with few time markers.

4) Analytical techniques of thermochrometry.

If interested, please contact Mike Daly mike.daly@earth.ox.ac.uk

 

 

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