Postgraduate Profiles

Katarina Bjorkman

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Thesis: Linking the crust-mantle evolution to mineral system distribution using U-Pb-Hf-O isotopes in zircons from the Marmion Terrane (3.0-2.7 Ga), Western Superior Craton, Canada

The flux of mass and energy from the mantle to crust is focused along deep lithospheric structures. Mineralisation typically involves the transfer of fluids into the crust. Therefore, mineral system distribution may be controlled by the lithospheric architecture. This study is aimed at linking the crust-mantle evolution to mineralisation through time and space across the Meso- to Neoarchaean.

We are using in-situ U-Pb, Lu-Hf and O isotopic studies in zircons to map major lithospheric discontinuities through time for their potential to focus large mineral systems. The geologically well-characterized Marmion Terrane (3.0 – 2.7 Ga), in the Western Superior Province of Canada contains a variety of mineralization which appear to cluster along terrane margins, providing a natural laboratory to better understand the controls lithospheric architecture has on mineral system distribution.

Why my research is important

This work will provide insight into fundamental Earth processes during the Archean and provide a tool to aid in mineral exploration targeting which can be applied globally.

The mechanisms and rates of growth and preservation of apparent episodic continental crust generation continue to be highly debated and remain enigmatic. Combined U-Pb-Hf-O systematics in zircons provides constraint on this fundamental debate by indicating the age of crystallization, age of source, and reworking history. Additional to temporal insights, by mapping out the lithospheric architecture spatially, we will be able to better understand relationships to mineral system distribution. When combined with whole rock geochemistry, petrography and stratigraphic and structural observations, this can also help to constrain the geodynamics which shaped the rates and preservation of both crust-mantle evolution and mineralisation.

Funding

Feb 2013

Feb 2017

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