Spring 2016 Update

Here’s what the Sedimentary Systems Research group is up to in the spring 2016 semester:

Ph.D. candidate Neal Auchter submitted his first paper as part of his dissertation research in January. This paper discusses intriguing deformation features in submarine slope strata of the Upper Cretaceous Tres Pasos Formation in southern Chile. We came upon this outcrop a couple of field seasons ago while mapping and were initially confused about the genesis of small-scale (up to ~meter of offset) extensional and compressional faults. The data Neal collected suggests a mechanism of deformation that occurred soon after deposition (shallow burial), with some component of gravitational influence, rather than a tectonic (e.g., uplift of the outcrop belt long after deposition/burial). Interestingly, the position and scale of deformation features are controlled, at least in part, by the depositional architecture. This manuscript is currently in review for Sedimentary Geology.


Photos of down-slope-influenced deformation (part of a figure for Auchter et al., in review)

M.S. candidate Kristin Chilton is right now analyzing the last set of samples that will make up her complete data set for her master’s project. Kristin is investigating paleo-circulation in the North Atlantic Ocean in response to global climate change at the Eocene-Oligocene transition (~34 Ma) via terrigenous grain-size analysis of deep-sea sediment cores. Preliminary results are intriguing and suggest a transient change in circulation at Oi-1 (Oligocene isotope stage 1), but more work is needed to test this. Kristin presented a poster about this work at GSA in fall 2015, which won best student poster. Congrats to Kristin!

M.S. candidate Sarah Jancuska finished the second of two field seasons down in southern Chile earlier this semester and is now poring over the data. Sarah is examining the sedimentology and stratigraphic architecture of deep-marine deposits at the transition from basin-plain/distal-levee to progradational slope systems. The photo below (taken by a drone) showcases part of the outcrop transect Sarah is working.

Drone photograph of the south face of Cerro Sol, Tres Pasos Formation, southern Chile.

Drone photograph of the south face of Cerro Sol, Tres Pasos Formation, southern Chile.

Ph.D. candidate Cody Mason is spending the bulk of his time this semester working on a manuscript related to a thermochronolgy and tectonics study in the Coachella Valley of southern California (see this abstract from AGU 2015 presentation). In addition, Cody is exploring various techniques to better understand his cosmogenic radionuclide results from Pleistocene alluvial deposits in Panamint Valley (e.g., methods in this Balco & Stone paper from 2005). Cody will be in Austin, Texas this summer doing another internship with the Statoil research group.

We also have Virginia Tech Geosciences undergraduate Taylor Sanchez doing research in our group this semester. Taylor is working with Kristin on the Eocene-Oligocene paleoceanography project and is focused on the coarse (sand, >63 µm) fraction of these dominantly muddy deposits. Taylor is acquiring images and then using the image-analysis method of Buscombe (2013) [i.e., we are using this MATLAB routine] to characterize grain size of the sand fraction. The photo below is one of hundreds of images that Taylor has generated so far this semester. Taylor will be continuing this work for part of the summer.

Stereoscope image of Oligocene sand from Newfoundland Ridge

Stereoscope image of Oligocene sand from Newfoundland Ridge

Three of the four graduate students in the group (Neal, Sarah, and Kristin) are all planning on defending in the fall, so things are quite busy around the lab!