Doctor of Philosophy
Dr. Neil Banerjee
Dr. Ed Cloutis
Dr. Gordon Southam
The Dome Mine in the world-class Timmins camp has produced over 16 Moz of gold during its 108 year production history. This gold endowment is the result of multistage enrichment of which the first stage is a set of ankerite veins that extend over 5,400 m in strike and 1,500 m vertically. A deposit wide geochemical study of the Dome ankerite veins was undertaken to characterize their genesis, geochemistry, and role in the deposit mineralization history. Samples and mapping from new and historic mine workings, bulk rock geochemistry, and stable isotope geochemistry were used to constrain the depositional context of the ankerite veins as forming syntectonically from auriferous metamorphic fluids, and provide insights into geochemical controls on vein formation. The δ18O values for dolomite from the ankerite veins show a trend of increasing δ18OVSMOW values from 10.8 to 14.9‰ downdip of the ankerite veins and to the northwest away from the Dome Fault Deformation Zone (DFDZ), which is likely a long-lived fluid conduit. Gold is intimately related to pyrite mineralization with contributions from multiple sources. This was investigated by a suite of high-resolution geochemical techniques including synchrotron-radiation X-ray fluorescence (SR-XRF). Three stages of pyrite growth were identified, each with a distinct gold and trace element fingerprint. These stages of pyrite growth and gold endowment are related to deposit wide fluid events. The application of high-resolution synchrotron techniques to ore deposit studies was developed and evaluated on a number of different types of auriferous samples from across the Timmins gold camp. These applications address the present challenges of today’s global minerals industry by quickly and effectively answering key questions regarding deposit formation and informing exploration strategies and extractive geometallury. This body of work addresses several key questions in the field of orogenic gold regarding fluid sources and key components of multi-stage deposit formation. It reveals the integral role of early carbonate veining and alteration at the Dome mine and that the ore system was fertile for a period of over 20 Ma with variability in gold tenor, trace element contents and redox throughout the deposit history.
Stromberg, Jessica M., "Geochemistry of the Dome Mine Ankerite Veins: Insights into the Multi-Stage Enrichment of a World-Class Orogenic Gold Deposit" (2017). Electronic Thesis and Dissertation Repository. 5090.
Available for download on Saturday, December 01, 2018