I am looking to admit a new graduate student to the Sedimentary Systems Research group to start in August 2017. This could be either a master’s or a Ph.D.
The project(s) for this incoming student would contribute to our growing research program in Paleogene North Atlantic paleoceanography. Specifically, we are generating terrigenous grain-size records from IODP Exp 342 sediment cores that span the Eocene-Oligocene Transition and early Oligocene (~36-25 Ma). These cores are from deep-sea contourite drifts on the Newfoundland ridges and record the history of ocean-basin-scale bottom current activity.
The Eocene-Oligocene Transition represent the most significant global climate shift of the past ~60 Myr, but the response of deep ocean circulation in the North Atlantic is still poorly understood. This research involves collaborations with geoscientists at Univ of Southampton (UK), Univ of Utah, and Univ of South Carolina who are generating different, but complementary, paleoceanographic records from the same cores. Thus, this work will likely involve working with other graduate students from these institutions.
See below for a recent conference abstract from our group with more details. Note that a future project may not look exactly like this, but this abstract will give you a sense of the type of work and the questions we are interested in.
For prospective students seeking a Ph.D., I’m open to your ideas for additional projects. It’s common for Ph.D. students to have multiple, concurrent projects that end up as separate stand-alone, published papers.
Below is an abstract at the AGU Fall Meeting 2016 about this work. A future project may not look exactly like this one in terms of the specifics, but it will be in the general area of North Atlantic paleoceanography:
Terrigenous grain-size record of the Newfoundland Ridge contourite drift, IODP Site U1411: The first physical proxy record of North Atlantic abyssal current intensity during the Eocene-Oligocene Transition
Atlantic Meridional Ocean Circulation (AMOC) is a vital process that helps to regulate global climate and support marine ecosystems. The timing and nature of the shift to modern AMOC, and especially to deep-water formation in the North Atlantic, has been a topic of ongoing study, with the Eocene-Oligocene Transition (EOT, ~34 Ma) being a potential focal point of this shift. However, the role played by abrupt EOT cooling in North Atlantic circulation remains unclear. Improved constraints on Paleogene circulation will provide insight into the sensitivity of AMOC to perturbations in global climate.
We obtained grain-size data from the terrigenous fraction of the mud-rich sediments of the Southeast Newfoundland Ridge contourite drift complex at IODP Site U1411, which is interpreted to have formed under the influence of the Deep Western Boundary Current. We analyzed 195 samples that span 150 m of stratigraphy from 36-26 Ma. The main objective was to use the ‘sortable silt’ fraction (10-63 µm) to generate a record of relative change in bottom-current velocity. These data are complemented with a record of the abundance and size of lithogenic sand (>63 µm).
Here we present U1411 sortable silt data as the first physical proxy record of abyssal current intensity in the North Atlantic, from late Eocene to mid Oligocene. Invigoration of North Atlantic deep circulation occurred gradually (over Myr timescales). We infer that deep circulation in the North Atlantic was not sensitive to the abrupt global cooling and Antarctic glaciation associated with the EOT. Rather, our data suggest that changes in North Atlantic circulation were likely governed by longer-term processes related to the opening of key tectonic gateways (i.e., the Greenland-Scotland-Faeroes Ridge, and the Drake and Tasman Passages). Lithogenic sand is nearly absent in the Eocene and then systematically increases in abundance from the earliest Oligocene through the mid Oligocene, which could represent bottom-current transport of an additional supply of terrigenous sediment during the Oligocene. Our findings have important implications for debate over the mechanisms responsible for carbon cycle perturbation associated with the Cenozoic initiation of sustained Antarctic glaciation.