Terrane fertility and the formation and distribution of orogenic gold deposits
The project aims to assess the fertility of different rock types for producing gold rich fluids during processes such as metamorphism and hydrothermal alteration. The project involves 1) evaluation of the Au content of different rock types using ultra low detection limit methods, 2) evaluation of the extent of mobility during for example metamorphism through mass balance between metal contents in suites of variably metamorphosed rocks, and 3) constraining the mineral reactions that control metals mobility and the conditions at which they occur. Field areas being investigated include the Abitibi greenstone belt, Canada, the Central Lapland greenstone belt in Finland and various Phanerozoic-aged metasedimentary orogenic belts.
The role of metamorphism in the production of metal rich fluids for hydrothermal ore deposits
A theme of my on-going research is the investigation of the extent to which metamorphism produces metal rich fluids for hydrothermal ore deposits. The key deposit types to which this applies are orogenic gold deposits although the approach is also applied to VMS deposits for which hydrothermal alteration in the oceanic crust (“seafloor metamorphism”) produces some of the metal rich fluids. Research questions of interest to me include identifying the mineral reaction that liberate the metals into the hydrothermal fluids, constraining the relative timing of these different mineral reactions with hydrothermal fluid flow, and identifying the critical conditions required for mobility of different metals.
Carbonation of the Arabian Nubian Shield of Egypt: Implications for large-scale CO2 fluxes in the Neoproterozoic
Carbonation occurs when certain rock types interact with CO2-rich fluids causing alteration and precipitation of carbonate. The Arabian-Nubian Shield (ANS), a Neoproterozoic aged orogen in NE Africa, contains large volumes of carbonate-altered rock. The Neoproterozoic Era was a period of tremendous climatic variability. The carbonation in the ANS implies very large fluxes of CO2 to the Earth’s surface, but the sources, flux rates or timing of flow of the CO2-rich fluid is not known. The carbonate-altered rocks also show a spatial association with gold deposits in the ANS but the significance of this relationship is poorly understood. This project aims to identify the sources and flux rate of CO2, the timing of carbonate alteration in the ANS, and the relationship between carbonation and gold deposition. The project also aims to describe and classify the serpentinite and listvenite altered ultramafic rocks that have formed during the alteration. Constraint of the source, fluxes, and timing of CO2-rich fluid flow that caused carbonate alteration in the ANS will improve our understanding of climatic evolution during the Neoproterozoic. Better understanding of the link between carbonate alteration and gold deposition in the ANS will allow development of more successful exploration models for gold deposits in Egypt.