The University of British Columbia

Tracing hydrothermal fluid flow in the crust requires a detailed understanding of the physical-chemical manifestations of the fluid system.  Detailed mapping of relative patterns of mineral alteration and geochemical metasomatism in high-temperature and magmatic hydrothermal systems has proven successful for defining both the evolution of the fluid and the far-field indicators of fluid flow.  In low temperature sediment-hosted hydrothermal systems, the physical-chemical expression of the fluid system may be subtle, especially at the distal margins of fluid circulation, owing to significant kinetic barriers to chemical alteration.  

The main objectives of my research are to:

1) Develop a combination of new and established analytical techniques better able to characterize the thermal, chemical and hydrological evolution of low temperature hydrothermal systems, particularly those hosted in sedimentary rock sequences.

2) Better constrain the distal manifestations of hydrothermal fluid flow and identify physio-chemical gradients that could provide exploration vectors toward ore in sediment-hosted hydrothermal systems.

Chemical disequilibrium between a fluid and wall rock will result in chemical reactions and the preferential partitioning of chemical components into the fluid or the rock.  Reaction fronts represent progressive stages of equilibration of the fluid with the rock.  In low temperature systems, these fronts may be manifested by geochemical fluxes, isotopic fractionation, textural re-equilibration, and thermal resetting of thermochronometers/thermometers.  

A classic example of low temperature hydrothermal systems are the Carlin-type Au deposits of northern Nevada, USA.   Carlin deposits are predominately sediment-hosted Au deposits formed by large hydrothermal systems, which typically exhibit subtle, spatially restricted patterns of alteration.  My research concentrates on the hydrothermal systems of the northern Carlin trend mineral district, which represents the largest known occurrence of Carlin-type Au deposits in the world.

My research combines the use of stable isotope and thermochronology studies  with more traditional approaches of detailed lithogeochemistry and mineral alteration studies in order to define both the distal signature of hydrothermal fluid circulation in low temperature systems and the temporal-spatial evolution of fluid.  Developing an understanding of the physical-chemical manifestations of fluid flow will not only develop new approaches for exploration vectoring in low temperature systems, but will also establish thermal-chemical-hydrological constraints on the genesis of Carlin-type Au deposits.  In a broader sense, it is anticipated that the research will refine models for the spatial-temporal evolution of low temperature hydrothermal systems. 

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