Mineralogical and geochemical approaches to tectonic problems

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The proposed work uses the mineral composition of rocks to better understand aspects of the Earth’s tectonic history. The first part of the work is carried out in the Scotian Basin, offshore Nova Scotia, where both oil and gas have been produced from deeply buried sandstones that are 100 to 150 million years old. I analyse minerals from the sandstones, to determine the original source of the sands that were deposited in large deltas. The rivers supplying sand to the deltas were likely controlled by the effects on the landscape of progressive opening of the North Atlantic Ocean and Labrador Sea. The type of sands transported by rivers influences the quality of the sandstones as reservoir rocks for oil and gas. The migration of fluids within the basin also influences reservoir quality. I will use evidence from mineral cements and their fluid inclusions to understand how movement of buried salt affected fluid migration and reservoir quality. A second part of the work uses minerals in igneous rocks such as granites to better understand where the parent magmas were derived from, where the rocks crystallised, and how they were altered by later ore-depositing fluids. This component of the work is directed at understanding better the tectonic history of continental areas behind active subduction zones. Undergraduate and graduate students will be educated in methods of geological problem solving using minerals that contribute to broader questions of tectonics.