New paper out in GSA Bulletin about submarine channel stratigraphy

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My collaborators and I have a new paper out in the journal GSA Bulletin about sediment transfer across deep-marine slopes as recorded in the stratigraphy of submarine channel deposits. (It’s worth mentioning that this paper is also open access!)

Deep-sea channels, as we can map them on the modern Earth surface, extend for 1000s of km into ocean basins and rival the planet’s biggest rivers as conveyors of sediment and other material. Much progress has been made in recent years in tools and technology for mapping and studying the ocean floor. Additionally, numerical modeling of the physics of sediment transport in the submarine realm is advancing our understanding of turbidity currents. However, ancient sedimentary deposits that are now exposed in outcrop provide the opportunity to examine the relationships of individual turbidity current event beds to the larger-scale stratigraphy that they construct. Examining the stratigraphic architecture allows for reconstruction of longer-term evolution of the depositional system.

With examples from exceptionally exposed strata from the Magallanes Basin in southern Chile, we emphasize the importance of the fine-grained and thin-bedded deposits that are preserved at the margins of sedimentary bodies we interpret as channels. Although the thick-bedded and coarse-grained deposits make up most of the volume of the composite features, it’s the margin deposits that contain the history of sediment transfer through the channel.

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VT Sedimentary Systems Research at AAPG 2014

The annual American Association of Petroleum Geologists (AAPG) conference and exhibition is next week (April 6-9) in Houston, Texas, and the Virginia Tech Sedimentary Systems Research group will be there in full force.

M.S. candidate Patrick Boyle is giving a talk on his thesis research on Tuesday afternoon at 2:20pm in the ‘Turbidites and Contourites’ session. Pat is nearly ready to defend his thesis (less than a month from now!), and this talk will be his chance to show off the work he’s done to the AAPG community.

  • Presentation Title: Investigating Slope-Parallel Processes in Mud-Dominated Depositional Systems Through Seismic Stratigraphic Mapping of Contourite Drifts: Newfoundland Ridge, Offshore Canada
  • Day / Time / Location: Tuesday, April 8, 2:20pm — Room 360

Ph.D. candidate Cody Mason is also presenting a poster and, like Neal, has some brand new data to share from recent field work in California. This poster is a chance for Cody to present preliminary ideas about the depositional evolution of the stratigraphic succession he’s been investigating.

  • Presentation Title: Architecture, Lithofacies, and Depositional Model for the Ballarat Sequence: A Mid-Pleistocene Fan-Delta Complex, Panamint Valley, California
  • Day / Time / Location: Monday, April 7, all day — Exhibition Hall, Booth 16B

Ph.D. candidate Neal Auchter is presenting a poster on his research on the Upper Cretaceous slope deposits of the Tres Pasos Formation in southern Chile. Neal recently returned from six weeks of field work down there and has much to share.

  • Presentation Title: Slope Evolution Revealed by Analysis of Sandstone Body Architecture, Tres Pasos Formation at Cerro Mirador, Chile
  • Day / Time / Location: Tuesday, April 8, all day — Exhibition Hall

Finally, I will be giving a brief, and hopefully provocative, talk at the SEPM evening research session on Monday evening. If you’ve never attended the SEPM evening sessions, they tend to be more lively and informal than the ‘normal’ technical sessions during the day. In the past these have been quite fun. This year the organizers invited me, Mike Blum (Univ of Kansas), Kyle Straub (Tulane), and Ashley Harris (Chevron) to discuss allogenic and autogenic controls on deep-water stratigraphy.

  • Day / Time / Location: Monday, April 7, 7-10pm — Hyatt Regency Houston, Arboretum 4-5 (2nd Floor)

Hope to see you there!

Tales From the Field

Much of the research the VT Sedimentary Systems Research group is currently conducting requires going to where the rocks/sediments are. What this mean is: travel, travel, and more travel.

Ph.D. student Neal Auchter and I spent several weeks in southern Chile doing field work on the Cretaceous Tres Pasos Formation. The photo below is from Neal’s primary field locale and highlights the stunning exposures of these submarine slope deposits. We spend so much time down there because (1) it’s very far away, so we only go once a year and (2) we need to build in days for the inevitable poor weather and the occasional logistical hurdle (e.g., vehicle trouble).

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Neal had a very productive field season and is coming home with tons of data, samples, and lots of ideas about these strata.

The other field-based project going on currently is related to a component of Cody Mason’s Ph.D. research. This work is out in desert of southeastern California and is focused on mid-Pleistocene alluvial and lacustrine deposits now cropping out on at the base of the west flank of the Panamint Range. The primary goal of this trip was to collect samples for cosmogenic radionuclide analysis, which involved power tools and a lot of sieving of sand in the field.

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I flew from South America to California to join Cody and his field assistant for the final couple days in the field. All went well and Cody will be moving on to the next phase of this project this spring and summer.

Winter 2014 Update

A quick update on happenings with the VT Sedimentary Systems Research group for winter 2014.

Ph.D. candidate Neal Auchter has been working hard the past couple weeks to prepare for the upcoming field season in Chilean Patagonia, which will be his second field season down there. Lots and lots of logistical tasks to do to prep for these international field expeditions. Neal will be down there for ~6 weeks this year.

Ph.D. candidate Cody Mason is also in field-prep mode, although he doesn’t head out to Panamint Valley, California until mid-March. He’s using this time to work up sedimentological data from the past two field seasons. The main goal of the upcoming field work is a sampling campaign, which is informed by the sed-strat information. Cody is also continuing to work up bedrock thermochronologic data for a tectonics project he’s working on with VT professor Jim Spotila.

M.S. candidate Patrick Boyle is in the final stretch of his master’s degree. After a very successful poster presentation at the AGU Fall Meeting in December, Pat now has all his data in good order and is busy writing up the results. He’s planning on defending in April. Pat will be the first graduate of this relatively new research group!

Undergraduate researcher Sarah Ault has moved on from Virginia Tech but is still working up some of the data she generated in my lab last summer and through the fall. Current undergrad researcher Chris Matthews is now helping with the final steps in the analysis of this data set, which the three of us will write up in a paper. Rachel Corrigan is a new undergrad researcher starting this semester and will be looking at the grain-size record of deep-sea sediments across the Oligocene-Miocene boundary.

Developing and refining the workflow for the particle size analysis research has taken a bit longer than anticipated, but I think we are getting really close to being able to generate a bunch of great data over the next couple of months. I’m really excited to see it all come together after all this hard work by me and these talented undergraduates.

Earlier this month I participated as a panelist on the International Ocean Discovery Program (the new IODP program) Science Evaluation Panel. This was my first experience reading/reviewing new ocean drilling proposals. I learned a ton, it was a really good experience. I will soon be heading down to Patagonia for nearly a month of field work with Neal (and some of my own) and to interact with the sponsor’s of that research as well. From Chile I will be flying straight to California to meet up with Cody in the desert for a couple of days of field work before heading home. The rest of the spring will be busy with co-teaching a grad seminar that will culminate in a six-day field trip, continuing the lab work, and guiding Pat through the end of his master’s.

VT Sed Systems at AGU Fall Meeting 2013

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A few of us from Virginia Tech Sedimentary Systems Research group will be attending and presenting at the 2013 American Geophysical Union meeting in San Francisco in a few weeks. Here’s a run-down of our activities:

Monday (morning):

  • Ph.D. student Cody Mason will be presenting a poster on a project he’s working on with VT faculty Jim Spotila. The session  (T11D) is titled The Pacific-North America plate boundary through time: Translation, rotation, erosion, and 4-D strain and Cody’s poster is: Kinematic history of the southern Santa Rosa Mountains using U-Th/He thermochronometry of apatite: An uplifted and tilted block in a dominantly transpressional tectonic regime.

Thursday (afternoon):

  • M.S. student Patrick Boyle is presenting his poster Cenozoic variations in the Deep Western Boundary Current as recorded in the seismic stratigraphy of contourite drifts: IODP Expedition 342, Newfoundland Ridge, offshore Canada in Session PP43A
  • I will be presenting a poster in Session EP43D titled Building a bridge to deep time: Sedimentary systems across timescales, which is a preview of sorts of a review paper in the works with several collaborators.

Friday (morning):

  • I’m co-chairing (along with Joris Eggenhuisen and Gary Parker) oral session OS52A titled Sediment transport by turbidity currents: Simulation and observations. This session starts at 10:20am in Moscone West 3009.

Friday (afternoon):

  • The morning oral session on turbidity currents I’m chairing has a companion poster session (OS53B) in the afternoon.

Looking forward to interacting with our friends and colleagues during the meeting. See you in San Francisco!

Fall 2013 Update

The fall semester is in full swing and the Sedimentary Systems Research group is busy with research and teaching. Refer to the Research page for general descriptions of the ongoing projects that are discussed below.

M.S. candidate Patrick Boyle is starting the second year of his master’s after a valuable industry internship experience in Houston this summer. Pat’s thesis research is focused on reconstructing the Cenozoic history of deep-sea sedimentation on the Newfoundland Ridge with an emphasis on the response of the abyssal Deep Western Boundary Current to past climate change. Pat is mapping the distribution of contourite ‘drift’ deposits using seismic-reflection data tied to chronological and lithological information from IODP Exp 342 cores. Pat will be presenting a poster about this work at the American Geophysical Union (AGU) meeting in San Francisco in December.

Ph.D. candidate Neal Auchter had a productive summer working on various components of his research. Neal’s work encompasses multiple scales. At the finer scale, Neal is interested in the stratigraphic record of submarine channel systems, especially the architecture that is produced as a result of channel migration. He is also investigating larger-scale, longer-term basin-filling patterns and history. Neal spent a lot of time this summer characterizing and interpreting outcrop data that was collected in February-March in Patagonia. He also completed a small pilot study to test the utility of strontium isotope stratigraphy with the limited carbonate material in the Magallanes Basin, which informs the design of a sampling campaign for the upcoming field season.

Ph.D. candidate Cody Mason is very busy processing and analyzing samples for a thermochronologic study he is doing with Virginia Tech faculty Jim Spotila (active tectonics, geomorphology). Cody will present some preliminary results of this work at AGU in December. Cody is also planning for a second field work excursion to Panamint Valley in California in October. This project aims to examine the role sediment flux (calculated from cosmogenic radionuclide-derived paleodenudation rates) has on stratigraphic architecture. This next field season will focus on creating a detailed stratigraphic framework with a combination of measured sections, facies analysis, and high-resolution mapping of the stratigraphic architecture. This framework will then be used to design the cosmogenic nuclide sampling plan. Neal will be heading out there with Cody to assist.

Undergraduate researcher Sarah Ault spent a good deal of the summer helping me test and establish sample preparation procedures for grain-size analysis of terrigenous deep-sea sediment. There was a lot of trial and error and a series of minor issues with laboratory equipment, but we now have a robust set of procedures and are now at full throughput. Data is being generated! Sarah is examining the controls on distinct cycles in these sediments that alternate from clay-rich to carbonate-rich beds at the 10s of cm scale. She will be using terrigenous grain-size analysis to test the hypothesis that the carbonate production was ‘diluted’ by varying influx of terrigenous material.

A new undergraduate researcher, Chris Matthews, started working in the lab last month. In addition to helping me analyze samples for longer-term research goals, he will be testing a widely used contourite facies model with quantitative grain-size data.

I’m very busy teaching this fall. I’m teaching the undergraduate Sed-Strat course for our geoscience majors (Pat and Neal are TAing this course), running the Seismic Stratigraphy course for the second time, and leading a grad seminar on sedimentary basins. Busy! And, as always, I’m working on a few manuscripts and proposals in between all of the teaching and mentoring.

Finally, we didn’t have any new graduate students join the group this fall, but I will be bringing in at least one, possibly two, grad students to start in August 2014. The deadline for applying is in January and I’ve already been corresponding with several prospective students. Please contact me if you’re interested in learning more.

Looking for a Graduate Student to Start Fall 2014

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I am looking for a new graduate student to join the Sedimentary Systems Research group at Virginia Tech. This student would start in August 2014 (applications due January 2014).

The research project will investigate the flow history of the Deep Western Boundary Current in the North Atlantic Ocean in response to significant past global climate change (specifically, at the Eocene-Oligocene and Oligocene-Miocene transitions). Flow history of this long-lived and globally important oceanic current will be reconstructed primarily from quantitative grain-size analysis of sediment cores from deep-sea ‘drift’ deposits of the Newfoundland Ridge. These data will be generated in laboratory facilities at Virginia Tech.

This project is associated with the broader scientific goals of Integrated Ocean Drilling Program (IODP) Expedition 342, which I sailed on as a participating scientist in summer 2012. More information about Expedition 342 here: http://publications.iodp.org/preliminary_report/342/342pr_5.htm

The scope of the research could be designed for either M.S. or Ph.D. level. For those students seeking a Ph.D. I’d like to hear ideas from the prospective student regarding the design of the project.

General information about the graduate program in the Dept. of Geosciences at Virginia Tech: http://www.geos.vt.edu/prospectivestudents/graduate.php

Learn more about VT Sedimentary Systems Research group: http://vtsedsystems.wordpress.com/

Please contact me if you’d like to learn more about this opportunity.

Dr. Brian Romans
Assistant Professor
Virginia Tech Geosciences
romans@vt.edu