Author Archives: Brian Romans

Core on Deck

A core being carried onto the catwalk by IODP technicians during Expedition 374

This is the phrase that participating scientists on IODP expeditions love to hear. When a new core is brought up to the rig floor of the JOIDES Resolution (the JR) from beneath the seafloor, the driller’s announcement of “core on deck” comes through the speakers in all the labs. At this point, multiple people leap into action and prepare for the new core. The IODP technicians get ready to accept the (hopefully full) 9.5 meter (~30 ft) long core. The drilling crew lays the core down horizontally on the drill floor, with the base of the core facing the ‘catwalk’, and a technician will get small piece from the base of the core (called the core catcher) and hand it off to one of the paleontologists.

The paleontology lab will immediately start to process the sediment to isolate and identify microscopic fossils and fossil fragments that will provide information about the age of the deposits (an application of paleontology called biostratigraphy). The rest of the core is put on a rack on the catwalk at which point the IODP curator will measure, assign identification to the core, and prepare it to be cut into 1.5 m long sections. Once the sections are created they are carried into the lab and put on a rack to equilibrate to surface temperatures (~4 hours).

The whole-round core sections will then go through a series of measurements (natural gamma radiation, magnetic susceptibility, P-wave velocity, bulk density) that aid the science party in characterizing the sediments even before they are split. The IODP techs will then split the cores, creating a ‘working’ half and an ‘archive’ half. The working half is sampled for additional measurements (density, moisture content, porosity, paleomagnetics, geochemistry, paleontology) and the archive half is thoroughly described. By the time any single core makes it through this process, the biostratigraphy lab team will have a preliminary age for that core. (In some cases, they have an age within 10 minutes of getting the core catcher!) The paleomagnetism lab team will also generate an age model based on magnetostratigraphy, which can be compared with the paleontology team. After ~24 hours of that core coming on deck, the geochemistry lab team will have initial results about general composition (e.g., % of calcium carbonate). This shipboard characterization provides the foundation for research that is done several years or even decades after the expedition.

Photo from a drone during Exp 374 taken by IODP photographer and imaging specialist Bill Crawford

The JOIDES Resolution (JR) is a unique science vessel. There are many ships that can perform any number of tasks for oceanographic and marine science. But, the JR is different because it’s a time machine. Only through deep coring into the seabed can we extract the record of past processes and environments.  The sound of “core on deck” is music to the ears of geoscientists on board excited to make new discoveries about how the Earth works.

More photos of Exp 374 here:

The Transit from New Zealand (43°S) to the Ross Sea (76°S)

We left port at Lyttelton, New Zealand just over a week ago and have been cruising almost due south ever since. In ~36 hours we will rendezvous with the R/V Palmer, a polar-class icebreaker, who will escort us through some sea ice. The sites we plan to drill are in ice-free areas (called polynyas) but we need the icebreaker escort to get us to those areas. At some point before our rendezvous with the Palmer, we will cross both the Antarctic Circle (66°33′,47”S) and the International Date Line. (However, we will be staying on NZ time to avoid mass confusion!)

The transit included a few days of some high winds and up to 6 m high waves. The Southern Ocean (the ocean surrounding the Antarctic continent) is notorious for this kind of weather and, although it wasn’t as bad as it can get, it was still a rough ride. Thankfully, I do not get seasick, but several others in the science party weren’t feeling particularly well. Here’s a video from the bridge of the JR the other day showing the ~6 m waves (with bonus albatross).

The seas have calmed down a bit and the science party has begun moving on to their shifts (either noon-to-midnight or midnight-to-noon). I’m writing this post as I try to remain awake after staying up all night in an attempt to transition to the midnight-to-noon shift. Up until today, the science party has been all in a normal day shift and working in their lab teams to learn procedures. It’s a challenge to effectively ‘practice’ what we’ll be doing without core actually coming up, but it’s still a good idea to get some familiarization with the equipment and overall workflow. I’ll write more about what analyses are done and what data are collected in a future post.

We’ve also spent time during the long transit to learn more details about the coring operations (via tours and presentations; photos below) and to write/edit the methods sections for the expedition report that we, as a collective, will be creating as we go.

When we get to our first drilling location we will have traveled 33 degrees of latitude (from 43°S to 76°S), or approximately 3,660 km (2,270 miles) during this transit. The Earth’s oceans are vast, the JR is designed for long transits to get to where we need to go.

Getting ready to set sail

I’ve been in Lyttelton, New Zealand (port town close to Christchurch) the past few days during our port call. The science party typically boards and moves onto the JOIDES Resolution (the JR) during port call to begin getting familiar with the ship, the labs, the people, and more before we actually depart. Meanwhile, the crew for the ship is offloading cores (and other freight) from previous expedition and preparing for the new expedition. All this typically takes a few days, which allows the scientists to get off the ship in the afternoons/evenings.

We set sail in just a few hours and it will be an ~8-day transit to our first coring site in the Ross Sea. During this transit we will continue to work in our lab groups (more about all that in a subsequent post) and get ourselves ready for the first core on deck.

Being able to get off the ship also allows getting a view looking back at the JR from off the ship, which is something we won’t be able to do for two months. What a beauty!

Finally, just wanted to point to this very nice story by the College of Science communications team that was posted on Virginia Tech News the other day. This is a wonderful overview of the objectives of the expedition.

Brian Romans to sail on IODP Exp 374 to study West Antarctic Ice Sheet history

I’m very excited to announce that I will be participating as a shipboard scientist on International Ocean Discovery Program (IODP) Expedition 374. This expedition leaves Christchurch, New Zealand on January 4th and will spend several weeks in the Ross Sea, offshore western Antarctica.

Here is a detailed description of the scientific objectives of this expedition (copied from the expedition webpage):

The Ross Sea West Antarctic Ice Sheet (WAIS) History Expedition will investigate the relationship between climatic/oceanic change and WAIS evolution through the Neogene and Quaternary. Numerical models indicate that this region is highly sensitive to changes in ocean heat flux and sea level, making it a key target to understand past ice sheet variability under a range of climatic forcings. The proposed drilling is designed to optimize data-model integration for improved understanding of Antarctic Ice Sheet mass balance during climates warmer than present. Core and log data from a transect of six sites from the outer continental shelf to rise in the eastern Ross Sea will be used to: (1) evaluate WAIS contribution to far-field ice volume and sea level estimates; (2) reconstruct ice proximal atmospheric and oceanic temperatures to identify periods of past polar amplification and assess forcings/feedbacks; (3) assess the role of oceanic forcing (e.g., sea level, temperature) on WAIS instability; (4) document WAIS sensitivity to Earth’s orbital configuration under varying climate boundary conditions; and (5) reconstruct eastern Ross Sea bathymetry to examine relationships among seafloor geometry, ice sheet instability, and global climate.

I am thrilled to be participating in this exciting expedition and looking forward to expanding the scope of the Sedimentary Systems Research group into ice sheet and glacially influenced marine sedimentary processes as well as investigating paleoceanographic records of the Miocene and Pliocene.

I will be posting to this site throughout the expedition, so stay tuned for updates from the JOIDES Resolution.

New paper on timing of deep-marine slope system evolution using zircon geochronology

We are pleased to share our newest publication coming out of the Chile Slope Systems project. This paper is led by Univ. of Calgary Ph.D. student Ben Daniels and is now online in the journal GSA Bulletin.

This study reports >6,600 new U-Pb zircon ages from the Upper Cretaceous Tres Pasos Formation in southern Chile. We’ve been investigating the sedimentology and stratigraphic architecture of these exceptional outcrops of slope strata for many years, but haven’t had a robust understanding of the timing until now.

Ben (with the help of others in the group) collected numerous sandstone samples for detrital zircons as well as two volcanic ash deposits. Together, the new geochronologic data constrain the age of distinct “phases” within the Tres Pasos Formation across a ~100 km long by ~2 km thick outcrop belt. With this framework, we discuss rates of progradation/aggradation, comparison to other well-studied slope/margin systems, and potential external controls on the basin-scale architecture. Additionally, we also include a discussion on the use of detrital zircon to calculate maximum depositional ages (MDAs) that will be of interest to anyone using detrital zircon geochronology for sedimentary system analysis.

The figure below (Fig. 2 from the paper) is a regional stratigraphic cross section showing the large-scale architecture, paleocurrent data, and these new U-Pb ages all in one chronostratigraphic framework.  

Huge congrats to Ben on spearheading this effort!

Welcome new Ph.D. student Drew Parent

I’m very happy to welcome Drew Parent to the VT Sedimentary Systems Research group. Drew is starting his Ph.D. in the department and his dissertation research will investigate the history and patterns of deep-sea sedimentation in the western North Atlantic Ocean in response to Cenozoic climate change. Drew will employ multiple methods, including: quantitative grain-size analysis of late Eocene through Oligocene cores from the Newfoundland Ridges obtained from IODP Exp 342, experimental (flume) investigation of fine-grained sediment transport (a collaboration with Dr. Kyle Strom and students from Virginia Tech Civil & Environmental Engineering), and regional seismic stratigraphic mapping of the U.S. Atlantic continental margin.

Drew is from Springfield, Massachusetts and received a Bachelor’s of Science in Geological Sciences from Salem State University in 2015. His undergrad thesis combined seismic sonar, stable isotopes, and radiocarbon dating to reconstruct the late Quaternary paleoenvironment of a glacial lake in northwest Iceland; this geophysical-geological approach fueled his interest in these types of investigations (similar to the research that will make up his Ph.D. here at Virginia Tech). Drew then went on to graduate school at Wright State University in Dayton, OH, where he finished a Master’s of Science in Earth and Environmental Sciences this past April (2017). Drew’s M.S. thesis is titled “Pre-Mt. Simon seismic sequences below west-central Indiana: local interpretation and regional significance”. This research employed regional 2-D seismic reflection and potential field data to assess the composition and deformational history of the poorly understood pre-Mt. Simon below the eastern U.S. mid-continent.

Welcome to the department and Sedimentary Systems Research group Drew! Check out Drew’s website here.

Congratulations to Cody Mason on finishing his Ph.D.!

I’m very happy to announce that Ph.D. candidate Cody Mason is now Dr. Cody Mason! Cody successfully defended in late April and submitted his finalized dissertation a few days ago. His research interests are in the interactions of tectonics, climate, and surface processes (erosion and deposition). Cody was co-advised by me and my colleague Jim Spotila (neotectonics, geomorphology) and ended up conducting two stand-alone projects, but both within the overall theme of climate-tectonic-surface process interactions and both projects examining normal-fault-bounded mountain ranges in California.

Cody’s project with Jim Spotila is titled “Two-phase exhumation of the Santa Rosa Mountains: Low- and high-angle normal faulting during initiation and evolution of the southern San Andreas fault system”. In this study, Cody and co-authors used (U-Th)/He thermochronometry combined with geologic mapping to test models about the timing and kinematics for initiation of the southern San Andreas system. This paper was submitted earlier this year and is currently in review.

figure from Mason et al. (in review); Two-phase exhumation of the Santa Rosa Mountains: Low- and high-angle normal faulting during initiation and evolution of the southern San Andreas fault system

The project that Cody and I worked on together is titled “Climate-driven unsteady denudation and sediment flux in a high-relief unglaciated catchment-fan system using 26Al and 10Be, Panamint Valley, California”. In this study, Cody calculated catchment-wide denudation rates from a now-exhumed Pleistocene succession of alluvial-lacustrine deposits at the mouth of a short and steep catchment in the Panamint Valley of California. These cosmogenic radionuclide-derived erosion rates are integrated with sedimentological characterization of the deposits to quantify the magnitude and variability in sediment flux in this catchment-fan system. Such catchment-fan systems are ideal natural laboratories to test hypotheses about the transfer of climate and/or tectonic signals to stratigraphy. Cody and I are currently putting the finishing touches on this manuscript and will be submitting it very soon.

figure from Mason & Romans (in prep); Climate-driven unsteady denudation and sediment flux in a high-relief unglaciated catchment-fan system using 26Al and 10Be, Panamint Valley, California

In addition to the above projects, Cody first-authored a paper that came out in Earth & Planetary Science Letters a few months ago that examines millennial to multi-millennial scale sediment mixing in the Mississippi River sediment routing system.

Fig. 4 from Mason et al. (2017); Climatic and anthropogenic influences on sediment mixing in the Mississippi source-to-sink system using detrital zircons: Late Pleistocene to recent; EPSL

Finally, I’m also happy to announce that Cody will be sticking around the Sedimentary Systems Research group for another couple years as a post-doctoral researcher. We will be applying this source-to-sink approach to the behavior of the Amazon sediment-routing system. More on this project later this summer.

Congratulations to Cody on his Ph.D. and these exciting contributions to geoscience!

Sedimentology and Scientific Ocean Drilling (Video)

The short (~4 minutes) video below features Pincelli Hull (Yale University) and me discussing the job of a sedimentologist on an IODP (International Ocean Discovery Program) expedition. If you’re interested in learning a bit more about what it would be like to participate in these expeditions, this video is a good introduction.

The video was produced by ScienceMediaNL and includes footage from IODP Expedition 342, which Celli and and I sailed on in 2012.

New paper on Cenozoic history of contourite sedimentation in North Atlantic Ocean

I’m excited to announce the publication of a new paper from our group out in Marine Geology titled “Cenozoic North Atlantic deep circulation history recorded in contourite drifts, offshore Newfoundland, Canada”.

This paper is based on the M.S. thesis work of former VT Sedimentary Systems Research graduate student Patrick Boyle. Pat used a grid of 2-D seismic-reflection data tied to nine IODP Exp 342 boreholes (drilled in 2012) that have robust bio- and magneto-stratigraphic age control. The resulting seismic stratigraphic framework is used to document the spatial and temporal distribution of deep-sea contourite drift sediments on the Newfoundland ridges and relationship to deep circulation history in the western North Atlantic Ocean.

The onset of bottom-current-controlled, terrigenous-dominated sediment deposition occurs at ~47 Ma and continues, generally, through the present. Unlike many other areas in the western North Atlantic Ocean, we did not identify a prominent (mappable) seismic horizon corresponding with the Eocene-Oligocene Transition. The paper discusses this and other paleoceanographic implications in more detail. Below is the summary figure of the paper, which puts the mapping of the sedimentary drifts into this broader context.

This paper provides important regional and long-term context for the many higher-resolution paleoceanographic studies based on IODP Exp 342 cores that are in the works. Additionally, this new seismic stratigraphic framework is helping design strategies for future ocean drilling proposals.

Congrats to Pat on getting his thesis published!

New graduate student Sebastian Kaempfe

I’m very happy to welcome Sebastian Kaempfe to the VT Sedimentary Systems Research group. Sebastian is starting a M.S. degree and his research will be part of the Chile Slope Systems program, which is in the first year of another three-year phase.

Sebastian is from southern Chile (Punta Arenas), not far from the field area that is the focus on this research. He received a Bachelor’s in Geology at the Universidad de Concepción in 2009. Sebastian came to us after finding out from a mentor and friend that we were doing sedimentary geology research in Chilean Patagonia. He approached us a few years ago and asked if he could help out as a field assistant and learn about what we were doing. This relationship grew and he’s now working on his own project in the group.

We are excited to have him on board. ¡Bienvenidos Sebastian!