Mudstones comprise as much as 70% of the fill in sedimentary basins and, as such, form a valuable archive of sedimentological and geochemical data. Indeed, the geological information retained in mudstones can instruct us of processes operating in the hydrosphere, biosphere and lithosphere though geologic time. My overarching research interest therefore relates to mudstone geochemistry and how it can be used in paleoenvironmental reconstruction, mineralizing processes and basin evolution.
Sediment-hosted massive sulphide (SHMS) deposits are commonly hosted in mudstones, and form anomalous accumulations of base metal sulphides in sedimentary basins. The distribution of SHMS deposits in the geologic record is not uniform, but rather sporadic, an observation that has led to theories linking seawater chemistry to mineralization processes.
However, there is growing evidence that SHMS mineralization rarely occurs in the water column, and that sub-seafloor processes in partially lithified sediments are important. Developing a more comprehensive understanding of diagenetic environments, where unlithified sediments undergo post-depositional chemical and physical transformations, is an important factor in the evolution of these systems. In modern environments sediments are typically seawater saturated, enabling the direct sampling of pore fluids for geochemical analysis; however, cementation and compaction during lithification can severely inhibit this approach in the geologic record, therefore it is necessary to utilize a variety of geochemical proxies. Combining various analytical techniques (e.g. major-minor-REE geochemistry, isotope analyses by SIMS, LA-ICP-MS) to trace diagenetic reactions in mudstones, and evaluating what makes the host rocks unique during periods of SHMS formation, is a primary research interest.