Unit Affiliation: Marine and Polar Geophysics, Lamont-Doherty Earth Observatory (LDEO)
The rocks beneath the coastal plain of Georgia were at the center of the most fundamental tectonic events to shape eastern North America: continental collision around 290 million years ago to form the super continent of Pangea; continental breakup leading to the formation of the Atlantic Ocean beginning around 230 million years ago; and one of the biggest magmatic events in Earth's history around 200 million years ago, the Central Atlantic Magmatic Province. A record of these events and possible relationships between them is preserved by structures in the crust of southern Georgia, including a suture between two different types of continent, the largest failed rift basin along the east coast of North America and igneous rocks from the Central Atlantic Magmatic Province. These investigators and a large team of graduate and undergraduate students are collecting seismic data that can be used to image structures in the crust to understand these tectonic events. Hundreds of geophones are being deployed along two ~300-km-long profiles across the suture and the basin, which record sound waves generated by a series of explosive charges spaced ~20 km apart. Geophones are also being deployed in a box focused on the basin to record explosive charges arranged in a grid. The speed that sound waves travel through rocks varies with composition, porosity, and other rock characteristics. The investigators are using travel-time tomography to create velocity models that reveal the distribution of igneous rocks, variations in the thickness of the crust and variations in crustal composition. Besides a better understanding of fundamental tectonic processes, other benefits of this program include training and education of students, and characterization of basins and igneous rocks that might be good targets for carbon sequestration.
OUTCOMES: Conference proceedings from 2 conferences have been published and one website has been created.
Management of the U.S. Science Support Program (USSSP) associated with the International Ocean Discovery Program (IODP)
Asthenospheric Melting and Melt-induced Evolution of the Lithosphere Beneath the Colorado Plateau and the Basin and Range from a Seismic Characterization of Mantle Layering
CAREER: Very Broadband Rheology and the Internal Dynamics of Plate Boundaries on Earth
Collaborative Research The North Anatolian Fault system in the Marmara Sea, Turkey Insights from the Quaternary evolution of a multi-stranded transform