Dan Gregory

My research focusses on in-situ analyses of various mineral phases in order to understand changes in fluid chemistry during mineral formation. The research outcomes have important applications to diverse fields that range from environmental chemistry, economic geology, to paleoceanography. Most of my work has focussed on laser ablation ICPMS analysis of the mineral pyrite with lesser emphasis on magnetite, hematite, chlorite, and titanite. My current research projects include:

• Investigating of how trace elements are held within minerals (lattice vs. nano-inclusions) using nano-techniques: atom probe tomography, nanoSIMS, transmission electron microscope, and synchrotron based X-ray absorption near edge structure analysis.
• Profiling the trace element content of pyrite formed in low temperature environments using LA-ICPMS. The goal of this study is twofold:
  • First is to understand the variations in ocean chemistry to track changes in paleo-oceans using pyrite proxy that can see through metamorphic overprint.
  • Second is to establish the range of “background” values that sedimentary pyrite can have. As pyrite chemistry becomes increasingly common in its use as a vector towards ore deposits, an established library of background pyrite compositions can be used to distinguish whether a geochemical anomaly is due to mineralization events or a change in depositional conditions.
• Examining the degree to which early pyrite trace element composition is retained through metamorphism. This is important because it has been proposed that pyrite trace element chemistry is preserved through to mid-greenschist metamorphism. Additional detail studies that can support this hypothesis would be a significant step in the development of the pyrite proxy tool and add to the great strength of this relatively new technique in paleo-ocean studies.
• Testing how trace element chemistry of pyrite varies within modern locations, but with drastically different water column redox conditions. This will involve LA-ICPMS analysis of pyrite and also traditional techniques including: sequential extractions; pore water trace element chemistry; Mossbauer spectroscopy; X-ray diffraction analysis; bulk sediment major, minor, and trace element analysis; and S-isotope analysis of AVS and CRS. This will provide important information on the controls of trace element content during pyrite formation and help interpret ancient pyrite chemistry record.
• Developing formation models and exploration strategies for low temperature Ni, Mo, PGE deposits, such as those found in the Yukon Territory and southern China.