Field-based investigation of structural and geochemical variability of gold-bearing veins in the Klondike Gold District, Yukon, Canada

Late-orogenic hydrothermal activity results in the formation of quartz and carbonate vein systems in the upper crust. It is an enigma why only certain hydrothermal pulses are associated with economic gold mineralization but others are not. Even in the same vein system, early veins are commonly barren whereas later vein generations carry significant gold mineralization.

This project will investigate possible controls on gold mineralization through a field study in the Klondike Gold District in Yukon, using geochemical and structural geology approaches. The ultimate aim is to generate a better, more detailed understanding of the variations in the gold metallogeny in the Klondike area, leading to a development in our general understanding of late-orogenic, gold-bearing hydrothermal vein and fluid systems. The genesis of gold in orogenic belts is a hotly debated subject: the fluid sources, fluid pathways, gold source, timing of mineralization, and trap mechanisms are all active research topics worldwide. Regardless of the fluid or gold source, all “orogenic” gold deposits are strongly structurally controlled, but the linkage between the structures, the tectonic evolution, and the fluid and gold sources (i.e. geochemistry) are poorly understood.

You will construct structural models of two known gold deposits, investigate both gold-barren and gold-bearing veins and vein generations using microanalytical methods and fluid inclusions studies, and tie these together in order to understand the hydrothermal and mechanical evolution of the system. The specific methodologies include field work and analytical aspects. You will make extended visits (core sampling and field work, minimum 3 months in total) to the Klondike Gold District in Yukon. The laboratory analyses include e.g. cathodoluminesence (CL) for indentifying the different vein and fluid inclusion generations; scanning electron microscope (SEM); Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) to characterize detailed mineral geochemistries; and the electron microprobe (EMP) facilities for gold analysis. Age determination of the different vein generations will be attempted if suitable material is found. The structural models can be built using e.g. MOVE or Leapfrog, depending on the scale of the models.

The project will shed light on the potential causes for the characteristics of and similarities between the different vein systems and, as such, be an important contribution to the enigma of multi-phase vein and gold deposition. It will elucidate the formation of orogenic gold systems in general, and also increase our understanding of the overall hydrothermal evolution of late-orogenic crust. The results are, therefore, expected to be globally important and generate up to three scientific publications, at least one of which will be suitable for submission to a high impact journal.

You will work under the supervision of Dr Taija Torvela, Dr Rob Chapman, and Dr David Banks within the Ores and Mineralization Group (OMG: https://www.facebook.com/Ores-and-Mineralization-Research-Group-OMG-1155557114600278) of the Institute of Applied Geosciences. This project provides specialist scientific training in: (i) structural analysis; (ii) state-of-the-art microanalytical and geochemical techniques; and (iii) industry-standard software skills. You will benefit from the experience of the OMG research staff working in the Klondike Gold District and nearby areas. In addition, the project will be supported by the existing post-graduate research projects at OMG addressing the detailed aspects of gold deposit genesis in the Scottish and Irish Caledonides and in Newfoundland. We anticipate that you will attend both national conferences (e.g. MDSG) and international academic/ industry facing conferences (e.g. SEG, SGA, PDAC, Roundup) according to your career trajectory (academia or industry). You would also be expected to contribute to the activities of the Leeds Chapter of SEG, with all the associated networking benefits.

The successful candidate will have a high 2:1 or a 1st from a Geological Sciences or similar programme. A masters qualification is highly advantageous, as is experience of publication or other extra-curricular research activities. Strong structural geology skills, including field work, and the ability to clearly communicate results are essential. Previous experience of ore deposit geology, especially gold deposit geochemistry, in either an academic or industrial context is desirable; additional specific experience in GIS, statistical analysis, microanalytical techniques, fluid inclusions, numerical modelling, and/or experimental work is desirable but not essential.