Fault & shear zone processes
Superior craton
My post-doctoral research focused on the westward extension of the Porcupine Destor Fault Zone across the Kapuskasing uplift in the Archean Superior craton, Canada. The goal of the project is to determine the expression and the extent of major gold-rich trans-crustal deformation zones across different rock types and crustal levels, and to identify processes controlling the distribution of orogenic gold systems. |
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Rae craton
The metamorphic and tectonic evolution of the south Rae craton in NWT involves substantial reworking during the Paleoproterozoic. Numerous crustal-scale shear zones preserve a record of deformation in the upper- and lower-crust, which helps unravel the complex history of mountain building in this craton. The characterization of these shear zones involves detailed mapping and structural analysis followed by in situ zircon, monazite and titanite U-Pb dating, Ar-Ar hornblende and biotite thermochronology, garnet Lu-Hf dating and various thermobarometric techniques including the use of isochemical phase diagrams and quartz-in-garnet barometry. The images to the left highlight some low- and high-temperature shear zones and also the use of field relationships and microstructural analysis in dating deformation. |
Resolving poly-deformation & metamorphism
Archean craton's have been affected by multiple mountain building events over their ~3 billion year history. Understanding distinct characteristics of these events is considerably difficult due to overprinting deformation and resetting of mineral ages. My work combines multiple techniques to see through these layers of metamorphic overprinting. For example, detrital zircon dating, which places age constraints on the deposition of sedimentary packages, is used to identify rock units of differing age that are used to inform subsequent tectonic events. Subsequent chemical analyses and dating of metamorphic minerals within these metasedimentary rocks, helps inform the formation and breakdown of petrogenetic indicator minerals during orogenesis.
In some cases, metamorphic mineral assemblage growth does not correspond with the U-Pb accessory mineral dates; In these circumstances I utilize garnet dating using the Lu-Hf system. By linking garnet geochronology and pseudosection analyses we are discovering evidence of poorly preserved metamorphic events and filling in critical gaps in the tectonic history of the poly-metamorphic south Rae craton.
In some cases, metamorphic mineral assemblage growth does not correspond with the U-Pb accessory mineral dates; In these circumstances I utilize garnet dating using the Lu-Hf system. By linking garnet geochronology and pseudosection analyses we are discovering evidence of poorly preserved metamorphic events and filling in critical gaps in the tectonic history of the poly-metamorphic south Rae craton.
Ore deposit geochemical evolution
This project (MSc work) documented the fluid evolution of a gold-bearing carbonate-replacement mineral deposit in central Yukon. Detailed petrography established a relative timing of mineralizing events (paragenesis) that laid the foundation for geochemical analyses. Fluid inclusion studies coupled with stable isotopic (C, O, S) and radiogenic (Sr) tracers were utilized to identify the gold-mineralizing fluid as originating from an intrusive unit distal to the deposit.
This conclusion was verified through U-Pb dating of monazite (59 Ma) associated with the mineralizing system and zircon (63 Ma) from the nearby intrusion.
Intriguingly, Paleocene gold deposits are rare in central Yukon, yet they occur in a restricted belt thought to be parallel to the western margin of ancestral North America. The metallogeny of this region is poorly understood and warrants further research.