The Sedimentary Systems Research group is quite busy this semester with various research, teaching, and other activities. Here’s what we’re up to:
Ph.D. candidate Neal Auchter is immersed in preparing the first manuscript to come out of his work the past few years. This first paper will highlight the occurrence and style of gravitational deformation features (i.e., faults/folds from down-slope movement) preserved in outcropping stratigraphy. What’s intriguing is the relationship of these deformational features with the stratigraphic architecture. Neal plans to submit this paper by December. Neal is also going to be presenting a poster at AGU in December about work he did during his internship this past summer with the Shell clastic sed/strat research team in Houston.
M.S. candidate Kristin Chilton is crazy-busy taking multiple courses and TAing the undergraduate Sed-Strat course. Even with all of this, she is making progress on her research investigating the response of North Atlantic deep-sea circulation to climate change at the Eocene-Oligocene Transition. Kristin will be presenting a poster at GSA in Baltimore in a few weeks sharing the preliminary results. Undergraduate researcher Shauna Flynn, also a co-author on this poster, is working in our lab this semester focused on characterizing the coarse fraction (>63 microns) of these dominantly muddy deposits.
M.S. candidate Sarah Jancuska is taking courses and working up the wealth of data she collected during the field season in Patagonia back in February-March of this year. Right now, Sarah is focused on compiling statistics from the measured stratigraphic sections (e.g., bed thickness, degree of bed amalgamation, etc.) to test ideas about the degree of large-scale confinement, or ponding, of these turbidite deposits.
Ph.D. candidate Cody Mason is TAing the course I’m teaching this semester, Seismic Stratigraphy, and working on the project he’s doing with Virginia Tech faculty Jim Spotila on the Late Cenozoic tectonic evolution of the Coachella Valley region of southern California. Cody, Jim, and their co-authors will be presenting at AGU in December highlighting some new helium thermochronology data.
Finally, my colleague here at Virginia Tech, Ken Eriksson, and I have a new Basin Research paper in press just this week that estimates sediment flux of a ~325 million-year-old river system sourced in the Alleghanian Orogeny mountain belt (the remnants of which are the Appalachian Mountains). We use a remarkable succession of prodeltaic tidal rhythmites as a high-resolution chronometer and make calculations of sediment load and yield. The figure below (Fig. 8 from the paper) compares our range of estimates with a database of modern rivers (Milliman and Farnsworth, 2011).
Uncertainties in these estimates arises from the true total duration of the stratigraphic interval of interest as well as inferences about the size of the paleo-catchment. However, even with conservative uncertainty ranges incorporated, the paleo-flux of this ancient river system is comparable to modern river systems such as the Fly, Po, and Eel. With the sediment yield estimates we then calculate denudation of the long-gone Alleghanian Mountains, which agrees with denudation estimates from independent methods. We suggest that such paleo-sed flux estimates can, in certain types of systems, provide additional insight into surface process response to tectonics in deep-time archives.