Assistant Professor in Geology and Geophysics
Dr. Obrist's current research interests include the understanding of sedimentary processes controlling basin fill and evolution. One of his goals is to decipher the signals in the sedimentary record to interpret past climate and tectonic processes and paleoenvironmental conditions at a variety of timescales.
He utilizes diverse tools, including field, sedimentological, geophysical, and laboratory techniques, that provide unique perspectives to interpret the geological record. He has been involved in projects attempting to understand deep-time paleoclimate changes during the Permo-Triassic mass extinction and during the Late Paleozoic Ice Age, Holocene climate and tectonic changes in Guatemala, and in hydrocarbon exploration projects in western Africa and Madagascar.
Phone: (573) 341-7879
332 McNutt Hall, Rolla MO 65409
The LIBRE [Lake Izabal Basin Research Endeavor] Scientific Drilling Workshop: Drilling and coring the Lake Izabal Basin
September 1, 2019 - August 31, 2021
Sponsor: NSF, National Science Foundation
Total Budget: $49,892.00
LIBRE-Lake Izabal Basin Research Endeavor
March 30, 2020 - May 31, 2022
Sponsor: Intl Continental Sci Drilling Program
Total Budget: $52,000.00
The Lake Izabal Basin in eastern Guatemala developed along the Polochic Fault, the northern fault of the Polochic-Motagua Fault System (PMFS), the onland extension of the North American and Caribbean plate boundary. In 1976, the plate boundary ruptured in a 7.5 Mw earthquake, killing >23,000 people and causing catastrophic damage to homes and other infrastructure in Guatemala.
Despite sharing characteristics with the North Anatolian, San Andreas, and Dead Sea faults, relatively little is known about this plate boundary. The Izabal Basin developed ~12 My ago and has accumulated >4 km of sediment because of continuous sinistral movement along the Polochic Fault. Presence of the northern strand of the Polochic Fault along the north shore of Lake Izabal, along with the thick sediment cover, make the site ideal for multidisciplinary study of past tectonic, climatic, volcanic, and biological changes in the area.
Our research project has two main objectives. First, we will drill, log, and core the Polochic Fault to investigate the loading state of the fault and assess seismic risk. Second, we will target the progradational infill of the Lake Izabal Basin along the depocenter migration axis, with the goal of recovering overlapping cores that contain a record spanning at least 1, and possibly as much as 5-10 My. Data from the cores will provide information about climate in the Neotropics over multiple glacial-interglacial cycles, the origin, extinction and migration of species in the area, and volcanic activity along the Central American volcanic arc.