This post is coming many months after it should, but better late the never! Congratulations to SSR graduate student Drew Parent on successfully defending his dissertation in December 2021 and officially graduating from the program and obtaining his Ph.D. in January 2022! Drew’s dissertation is titled Deep-marine depositional systems of the western North Atlantic: Insights into climate and passive-margin evolution, comprising three chapters that span a diverse range of approaches and topics, including experimental sedimentology, paleoceanography, and source-to-sink analysis, with applications focused on the North Atlantic Ocean and eastern margin of North America:

(1) Comparative analysis of flume experiments and natural systems: Implications
for application of sortable silt to deep-sea bottom-current reconstruction

This work summarizes Drew’s contributions to a collaboration we had with Kyle Strom and his Fluid & Sediment Dynamics group in Civil and Environmental Engineering here at Virginia Tech. This project aimed to test aspects of the widely used physical paleoceanographic proxy known as ‘sortable silt’ in an experimental flume. Our first paper, which summarizes the experimental design and basic results, was published in Sedimentology in 2021. Drew’s chapter about this research focuses on the implications to the usage of sortable silt for paleoceanography, including quantitative comparison with published data from the literature. We plan to submit this manuscript later this year.

(2) Eocene-Oligocene intensification of the Deep Western Boundary
Current in the North Atlantic Ocean

This chapter applies the sortable silt proxy (mentioned above) to a ~9 million-year-long succession of deep-sea contourite drift deposits on the Newfoundland ridges that includes the Eocene-Oligocene Transition (EOT; ~34 Ma). The EOT is the most significant climate transition of the past ~60 million years of Earth history and is characterized by significant global cooling and rapid expansion of land ice on Antarctica. Drew’s research built on data collected by former SSR student Kristin Chilton (M.S., 2016) and investigates the long-standing hypothesis that North Atlantic deep circulation intensified during the EOT. Drew’s work suggests that deep ocean circulation did indeed intensify over this time, but gradually over million-year timescales. This manuscript will be submitted this summer (once our co-authors give it a thorough review!).

(3) Sediment routing system connectivity of the mid-Atlantic U.S. margin
during the Early Cretaceous: Insights from detrital zircon geochronology

This final chapter is focused on the western part of the North Atlantic Ocean and continental margin of eastern North America. While this work also highlights deep-marine sediments and processes, it’s distinct from chapters 1 and 2 in that it ventures further back in time and applies different methods. Drew generated new detrital zircon geochronology data in a proximal-distal transect for the Early Cretaceous as a way to examine the linkage of onshore (fluvial) depositional systems to offshore (turbidite fan) systems, which has implications for broader landscape reconstructions and evolution.

Graduate students finishing is such a bittersweet event — when they succeed that means they leave! I am so happy to have worked with Drew on these projects and look forward to getting this science out to the community and working on new collaborations in the future. Drew also TA’d several times during his time here becoming a talented educator and mentor in addition to researcher. Drew is now working as a geoscientist at Shell in Houston, Texas. Congratulations Drew!!