Date of Award

Spring 1-1-2017

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

First Advisor

Alexis S. Templeton

Second Advisor

Brian Hynek

Third Advisor

Boswell Wing

Fourth Advisor

John Spear

Fifth Advisor

Stephen Grasby

Abstract

Sulfur is one of the most ubiquitous elements in the universe and one of those that is crucial for life, as we know it. This graduate dissertation presents the culmination of work conducted to better understand biological and geochemical processes related to sulfur cycling at a sulfur-dominated field site in the Canadian High Arctic. This site, situated in a valley called Borup Fiord Pass, provides a unique environment where sulfide-rich fluids emerge from a glacier and form large deposits of ice that become covered in elemental sulfur. The role of biology is compelling and yet challenging to define in each step of sulfur cycling at Borup Fiord pass, whether one considers the origin of the sulfide (presumed biological sulfate reduction in the subsurface) or one focuses on the processes driving sulfur oxidation and stabilization at the glacier’s surface. This dissertation presents results from a field expedition in 2014 as well as detailed mineralogical and spectroscopic analyses of sulfur-rich materials returned from the field. The importance of sulfur and carbonate minerals at this site is considered. Also, analyses of materials within pyrite alteration features in the valley are explored. These features appear to represent emplaced subsurface sulfide ores, which have been subsequently leached near the surface, forming gossanous structures. The geochemistry and mineralogy of these features is explored, as well as is their potential to serve as analogs for the exploration of Mars. The dissertation then concludes with some consideration of potential future work to be considered as well as a recapitulation of the current state of knowledge of processes at Borup Fiord Pass.

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