About the Project
This project is one of a number that are in competition for funding from the NERC GW4+ DTP. The GW4+ DTP consists of the Great Western Four alliance of the University of Bath, University of Bristol, Cardiff University and the University of Exeter plus six Research Organisation partners. The partnership aims to provide a broad training in earth and environmental sciences, designed to train tomorrow’s leaders in earth and environmental science. For further details about the programme, please see http://nercgw4plus.ac.uk/
Background
Orogenic gold deposits have strong structural controls on their location and geometry at all scales. However, it is unclear how structures link across different scales to control mineralization, what time scales are involved, or whether multiple deformation/mineralization events are necessary to create a large deposit. This project aims to improve our understanding of structural controls on gold deposits in four dimensions, using the Mako Volcanic Belt in Senegal as a natural laboratory. The Paleoproterozoic of West Africa is a world-class Au province, with resources of c. 9896 tons. The Mako Belt is located in the Kédougou-Kéniéba inlier in eastern Senegal, and comprises a package of volcanic and volcaniclastic rocks intruded by 2.2 to 2.0 Ga plutonic complexes. Two significant subparallel lineaments, the Main Transcurrent Shear Zone and the Sabadola-Sofia Structure host > 5Moz of economic gold mineralisation, including the Massawa Au deposit and Sofia satellite deposit (Fig. 1 and 2).
Project Aims and Methods
The aim, to use the Mako Belt to improve our understanding of structural controls on gold deposits in four dimensions, will be addressed through the following research questions (RQs):
1. How do key structural geometries in orogenic deposits vary and link across scales?
2. Is a change in stress regime associated with mineralization?
3. If so, what is the spatial and temporal scale of this change?
4. Can the above be used to predict the location and quality of future resources?
RQs1 and 2 will be addressed through detailed structural, lithological and alteration mapping of exposure and drill core at the m to 100 m scale. This will be extended to the μm-scale using petrography, SEM-EDS, EBSD, XRF and LA-ICP-MS analyses, and to the km-scale with geophysical interpretation. The spatial aspect of RQ3 will be addressed by integrating results from RQs1 and 2 with published work from the wider region, while the temporal aspect will be addressed by attempting to date mineralisation and deformation. Lastly, RQ4 will be addressed through a prospectivity analysis of the belt, incorporating novel fractal methods of assessing the structural controls on spacing and distribution of mineralization.
Funding Notes
NERC GW4+ DTP funding is for 3.5 years and is open to UK and EU applicants who meet the residency eligibility criteria.
A studentship will provide UK/EU tuition fees, a stipend in line with the RCUK rate (£14,553 per annum for 2017/18) and a generous budget for research expenses and training.
For further information including additional details on eligibility criteria, funding and how to apply, please http://www.cardiff.ac.uk/study/postgraduate/funding/view/nerc-gw4-doctoral-training-partnership-phd-projects-in-the-school-of-earth-and-ocean-sciences
References
• Goldfarb, R.J., and Groves, D.I., 2015. Orogenic gold: Common or evolving fluid and metal sources through time: Lithos, v. 233, p. 2–26, doi: 10.1016/j.lithos.2015.07.011.
• Lambert-Smith, J. S., Lawrence, D. M., Vargas, C. A., Boyce, A. J., Treloar, P. J., & Herbert, S. 2016. The Gounkoto Au deposit, West Africa: Constraints on ore genesis and volatile sources from petrological, fluid inclusion and stable isotope data. Ore Geology Reviews, 78, 606-622. doi: 10.1016/j.oregeorev.2015.10.025.
• Phillips, G.N., and Powell, R., 2015, A practical classification of gold deposits, with a theoretical basis: Ore Geology Reviews, v. 65, p. 568–573, doi: 10.1016/j.oregeorev.2014.04.006.
• Treloar, P.J., Lawrence, D.M., Senghor, D., Boyce, A., and Harbidge, P., 2014. The Massawa gold deposit, Eastern Senegal, West Africa: an orogenic gold deposit sourced from magmatically derived fluids: Geological Society London, Special Publications, 393, 135-160.
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