Virginia Tech sedimentary geoscience trip to Outer Banks, NC

The broader Virginia Tech sedimentary geoscience group (faculty and graduate students of VT Sedimentary Geochemistry and VT Sedimentary Systems and related disciplines) just returned from a six-day field trip visiting locations in the Outer Banks barrier island system of North Carolina. The trip was the culmination of a grad-student seminar this spring semester on coastal sedimentary environments. The students researched topics of interest, identified appropriate locations, designed field activities, and then led that day of the trip. The nine graduate student participants collaborated to design, write, and produce a field guidebook as well.

Topics of interest included: sediment transport dynamics, facies distribution and stratigraphy, biology/ecology of coastal environments, and anthropogenic effects/activities (e.g., beach nourishment). Field activities included: grain-size analysis (using sieves), beach profiling, trenching, push coring, and lots of primary observation.

Most of us in this group study sedimentary rocks so just getting to watch sediment transport happen before our eyes and make the connection to deposits that (might) get preserved into the rock record was an overarching objective.

In addition to the field locales, we had great visits to the UNC Coastal Studies Institute and the Army Corps of Engineers Field Research Facility. Huge thanks to our hosts, these visits added a lot to our trip.

The photos below summarize just some of the trip.


Day 1: unnourished beach at Duck; “outcrop” of eolian cross-stratification; beach profiling at Nags Head; eolian ripples/dunes at Jockey’s Ridge State Park

Day 2: Coring the foreshore; Examining coarse layers in foreshore; Coring the back-barrier; Well-developed microbial mat in estuarine deposits

Day 2: Coring the foreshore; Examining coarse layers in foreshore; Coring the back-barrier; Well-developed microbial mat in estuarine deposits

Day 2: Watching sand move on the south side of Oregon Inlet

Day 2: Watching sand move on the south side of Oregon Inlet


Day 3: Discussing beach-to-overwash-fan transition; Exploring overwash fan; Push coring estuarine sediments; View of barrier island facies tracts from Cape Hatteras lighthouse


Day 4: Exploring the wetlands and swamps of the coastal plain at Alligator River National Wildlife Refuge.


Day 5: Exploring Currituck Sound (large estuary behind barrier island) by pontoon boat; Taking salinity and pH measurements; Examining estuarine mud via push cores.


Day 6: Visit to the Army Corps of Engineers Field Research Facility; Back to Jockey’s Ridge State Park to to examine grain-size trends in eolian landforms.

Here’s the group (minus one grad student) on the final afternoon at Jockey’s Ridge State Park.




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!

Drone video of Patagonian outcrops

We tested out using drone-based photography this field season for the Chile Slope Systems project. There’s a lot of potential with this technology for the high-resolution stratigraphy work we do. Simple, but fundamental, visualization is the most obvious value. Getting a view of impossible-to-get-to outcrop faces is a game-changer.

Here’s a ‘fly by’ video taken of the Rio Zamora outcrops that Ph.D. candidate Neal Auchter is working on. The 2-minute video starts lower in the section highlighting the outcrops in the river canyon and then the drone turns up a side creek to show the overlying strata.

IODP Expedition 342 — Episode #8 of documentary film series

The 8th (and final) installment of the documentary film series on IODP Expedition 342 is now out. The expedition to drill and recover sediments from the Newfoundland Ridge that contain climate archives going back >50 million years was over three years ago (summer 2012) and much work has been done since.

This episode summarizes the post-cruise science meeting we just had in September 2015 where all the participating scientists get together to share the latest on their research and to re-kindle collaborations.

Ultimately, all this work is strengthened through multi-disciplinary collaborations — this meeting was critical to keeping the momentum going. I’m definitely excited about all the science that will come out of this effort.

To view all the past episodes and the 20-minute documentary, go to this page.

Fall 2015 Update

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.

Review paper on signal propagation in sedimentary systems by Romans et al.

I’m pleased to announce the publication* of a comprehensive review paper of signal propagation concepts in sedimentary system analysis in the journal Earth-Science Reviews. My co-authors and I initiated the idea for this review way back in the spring of 2013. The notion that tectonic and climatic changes can be recorded in erosional landscapes and the depositional record as ‘signals’ for geologists to extract and examine has been around for decades, if not centuries. However, more recent ideas concerned with how such signals move through the landscape — and with that movement, how the signal of interest may lag, be dampened/amplified, or even destroyed — deserved a synthesis in our opinion.

The illustration below is the first figure of the paper and an attempt to summarize the idea of signals and signal propagation conceptually and schematically. We focus on sediment supply as the main ‘carrier’ of signals from source to sink.

We don’t set out to solve all the problems and answer all the questions related to signal propagation in this review. Rather, our aim is to present the ‘state of the art’ and identify the most interesting questions to a broader Earth science readership with the hope that researchers in overlapping fields (e.g., geomorphology, climatology, oceanography, tectonics, ecology, biogeochemistry, and many more) find some value in our perspective.

You can find a link to the paper on the Publications page.

* this is the online early (‘in press’) version of the paper, which has a DOI and can now be cited

Summer 2015 Update

It’s getting hot and humid here in Blacksburg, so summer is in full swing. The Sedimentary Systems Research group is scattered a bit as three of the four graduate students (Sarah Jancuska, Neal Auchter, and Cody Mason) are away doing internships in Texas. I saw them and many other colleagues/friends at the recent AAPG conference in Denver, which turned out to be a very good meeting for us. Cody and Sarah both presented posters and Neal gave a great talk.

Master’s candidate Kristin Chilton is here this summer and she is neck-deep in sample preparation for her project. Kristin is building on a preliminary dataset that undergraduate researchers (all now graduated) and I generated to examine the variability in abyssal bottom-current intensity across the Eocene-Oligocene Transition (~34 Ma). Kristin added to this dataset this spring and the preliminary results suggest there is a change that corresponds with the transition, but (as always) it may not be as straightforward as we predicted. She will be working this summer to prep many more samples for grain-size analysis to better constrain the problem.

I am heading to the NOC (National Oceanography Centre) in Southampton, UK, next week to give a talk and work with some collaborators on this same Eocene-Oligocene Transition effort. Following that, I’ll be attending the IODP (International Ocean Discovery Program) Science Evaluation Panel meeting in Brest, France.

Sed Systems Research group at AAPG 2015

aapgNext week is the annual meeting of the American Association of Petroleum Geologists (AAPG) in Denver, CO. Sedimentary geology plays an important role in AAPG so there will be a strong contingent of the Sedimentary Systems Research group there presenting our latest research. As you’ll see below, the majority of our presentations are updates on the multi-disciplinary and multi-institutional Chile Slope Systems project, which had an incredibly productive past year.

[Unfortunately, I can’t link to static pages of each abstract — they have one of these systems where you have to log in and create an itinerary and all that. The entire technical program is here.]

Monday, June 1st:

  • Steve Hubbard (Univ of Calgary) is presenting a poster (Brian Romans is a collaborator and co-author) in the SEPM Research Symposium Channels: From Geomorphic Expression to Stratigraphic Record with a poster titled “How many turbidity currents pass through a submarine channel and what is their stratigraphic expression?” I know you want to know the answer to that question.
    • when: 8:30am-5:00pm
    • where: Exhibition Hall

Tuesday, June 2nd:

  • Brian Romans is co-chairing the first of two oral sessions as part of the SEPM Research Symposium Channels: From Geomorphic Expression to Stratigraphic Record, which will include talks from Mike Blum, John Holbrook, Kyle Straub, and many more. (And make sure to check out the second oral session later that afternoon.)
    • when: 8am-11:50am
    • where: Four Seasons Ballroom 4
  • Casey Meirovitz (Univ of Utah) is presenting poster (Brian Romans is a co-author) in session ACE 13 titled “Quantifying inter- and intra-channel architecture controls on reservoir performance in a deep-water slope channel system, Tres Pasos Formation, Magallanes Basin”
    • when: 8:30am-5:00pm
    • where: Exhibition Hall
  • Ph.D. candidate Cody Mason is presenting poster in session ACE 04 titled “Quantifying sediment supply in stratigraphy using cosmogenic nuclides: Insights from the Pleasant Canyon complex, Panamint Mountains, California”
    • when: 8:30am-5:00pm
    • where: Exhibition Hall
  • Jake Covault (Chevron) is giving a talk (Brian Romans is a collaborator and co-author) in the SEPM Research Symposium Channels: From Geomorphic Expression to Stratigraphic Record with a poster titled “Geomorphic and stratigraphic records of the composite evolution of submarine channels”
    • when: 2:20-2:40pm
    • where: Four Seasons Ballroom 4
  • Ph.D. candidate Neal Auchter is giving a talk in session ACE 04 titled “Outcrop example of intrastratal slope deformation controlled by depositional architecture, Tres Pasos Formation, Magallanes Basin, Chile”
    • when: 4:45-5:05pm [last talk of the day, stick around for it!]
    • where: Room 605/607

Wednesday, June 3rd:

  • Allie Jackson (Univ of Utah) is giving a talk (Brian Romans is a co-author) in session ACE 04 titled “Characterizing static reservoir connectivity of deepwater slope deposits using sub-seismic outcrop-based facies models, Tres Pasos Formation, Magallanes Basin, Chilean Patagonia”
    • when: 8:45-9:05am
    • where: Room 501/502/503
  • Lisa Stright (Univ of Utah) is giving a talk (Brian Romans is a co-author) in session ACE 04 titled “Optimizing the preservation of deepwater intra-channel architecture and model connectivity during upscaling, Tres Pasos Formation, Magallanes Basin, Chilean Patagonia”
    • when: 10:30-10:50am
    • where: Room 501/502/503
  • Sarah Jancuska is presenting a poster in session ACE 00 titled “Stratigraphic expression of the transition from basin plain to slope sedimentation in outcropping strata of the Magallanes Basin, Chilean Patagonia”
    • when: 8:30am-noon
    • where: Exhibition Hall
  • Daniel Niquet (Univ of Calgary) is presenting poster (Brian Romans is a co-author) in session ACE 04 titled “The orientation of sandstone-filled U-shaped trace fossils as indicators of deepwater channel axis position, Tres Pasos Formation, Chile”
    • when: 8:30am-noon
    • where: Exhibition Hall
  • Ben Daniels (Univ of Calgary) is presenting poster (Brian Romans and Neal Auchter are co-authors) in session ACE 04 titled “Constructing a seismic-scale 3-D geo-model of stacked slope channel deposits grounded in high-resolution outcrop observations, Magallanes Basin, Chile”
    • when: 8:30am-noon
    • where: Exhibition Hall


Photos of Patagonia 2015 Field Season

The 2015 field season for the Chile Slope Systems project is now over and a great success. Despite some not-so-great weather towards the end of the 7-week season the team was very productive. Ph.D. candidate Neal Auchter and M.S. student Sarah Jancuska amassed an impressive amount of data this season.

Here are some photos (captions are below each photo):


Neal and Sarah measuring section along Rio Zamora. The first half of the field season was unusually dry and the river level quite a bit lower. We were able to see some new section that is typically under water!


Neal with Rio Zamora in the background. The outcrops Neal is working up are a result of rapid incision by this river over the past several thousand years, which has produced some magnificent exposures along the river canyon walls.


We did a bit of mudstone sampling this year.


I was fortunate enough to be able to attend a trip to the Argentine side of the border where these same Upper Cretaceous foreland basin strata are exposed. This outcrop, not far from Perito Moreno glacier, highlights some fascinating transitional flow deposits of the Punta Barrosa Formation. These rocks are currently being studied by the Stanford Project of Deep-water Depositional Systems group.


Stunning view of Upsala glacier in Argentina while examining the older part of the basin history.


Typical Patagonia traffic jam.


What I ate for lunch most of the field season: canned tuna, avacado, and hot sauce on a cracker.


Some spirited debate during our sponsor’s trip regarding the nature of inclined surfaces in submarine channel strata.


A view of Cordillera Manuel Senoret from one of the areas worked up this year by a Univ of Calgary student as part of the collaborative Chile Slope Systems effort.