Assistant ProfessorResearch Interests
My overall research objective is to utilize the sedimentary record to investigate and understand past and present Earth conditions. The sedimentary record is a representation of Earth surface processes through time and, as such, can be analyzed to reconstruct ancient environments as they relate to tectonism, climatic and sea-level fluctuations, oceanic conditions, and intrinsic dynamics of the system. My Ph.D. research was completed in 2008 and was focused on ancient and modern deep-marine depositional systems with an emphasis on the distribution of terrigenous sediment in basins adjacent to active continental margins. Preserved strata in these settings are commonly the most complete record of the transfer of sediment from continents to oceans over geologic time scales. Analyses of modern and Recent systems are important for deciphering relative contributions of factors controlling distribution and timing of sediment delivery to deep-marine basins. Additionally, the character of the sediment itself (e.g., composition, age, etc.) holds clues to the nature of eroded orogenic belts.
As of August 2011, I am now on the faculty in the Department of Geosciences at Virginia Tech. Interested students can find my contact info here.
I also write a blog called Clastic Detritus where I share photographs from field work and discuss recent papers of interest.
Information about a few projects I worked on for my Ph.D.:
(1) Evaluating terrigenous sediment flux to a deep-marine basin at millennial time scales, Holocene Santa Monica Basin, offshore California
Seismic-reflection profiles tied to a radiocarbon-dated core are used to map the distribution (pictured right) and assess timing of turbidity current deposits over the past 7,000 years in Santa Monica Basin, offshore southern California. Variability in sediment delivery to the basin is strongly controlled by a combination of climatic variability and changes in sediment dispersal pathways in the staging area.
A journal article about this work was published in October 2009 in GSA Bulletin.
Romans, B.W., Normark, W.R., McGann, M.M., Covault, J.A., and Graham, S.A., 2009, Coarse-grained sediment delivery and distribution in the Holocene Santa Monica Basin, California: Implications for evaluating source-to-sink flux at millennial scales: GSA Bulletin, v. 121, p. 1394-1408. doi: 10.1130/B26393.1 [link] [download PDF]
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(2) Outcrop study of Cretaceous slope deposits, Magallanes foreland basin, southern Chile
Spectacular exposures of the Upper Cretaceous Tres Pasos Formation in southern Chile provide a unique opportunity to examine the lithofacies, architecture, and stratigraphy of a large-scale prograding delta- slope system in detail. Over 600 m (2,000 ft) of stratigraphy is exposed across a 3 km-long continuous outcrop face at Cerro Divisadero (pictured left).
A paper summarizing this work was published in the journal Sedimentology in March 2009:
Romans, B.W., Hubbard, S.M., and Graham, S.A., 2009, Stratigraphic evolution of an outcropping continental slope system, Tres Pasos Formation at Cerro Divisadero, Chile: Sedimentology, v. 56, p. 737-764. doi: 10.1111/j/1365-3091.2008.00995.x [link] [download PDF]
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(3) Detrital zircon ages and other provenance indicators for the northern Magallanes Basin: Evolution of sediment dispersal patterns during foredeep filling
This study, also in southern Chile, focuses on more regional, basin-scale relationships. Over 450 new detrital zircon ages from the Cerro Toro, Tres Pasos, and Dorotea formations are integrated with previously published ages from the underlying Punta Barrosa Formation to evaluate changes in sediment source area during the 20 m.y. basin-filling history. Results show that pre-foreland rift-related terranes (Upper Jurassic) were incorporated into the Andean fold-thrust belt and being denuded by the latest Cretaceous. These data also address basin-scale stratigraphic relationships of the large-scale prograding delta system, demonstrating the utility of provenance indicators when biostratigraphy or absolute dating is poor or unavailable.
A paper summarizing this work is in the October 2010 issue of Basin Research:
Romans, B.W., Fildani, A., Graham, S.A., Hubbard, S.M., and Covault, J.A., 2010, Importance of predecessor basin history on sedimentary fill of a retroarc foreland basin: Provenance analysis of the Cretaceous Magallanes basin, Chile (50-52S): Basin Research, v. 22, p. 640-658, doi: 10.1111/j.1365-2117.2009.00443.x [link] [download PDF]