LDEO Research Blogs

  • The goal of the Eastern North American Margin Community Seismic Experiment is to understand the breakup of ancient continents that led to the formation of the eastern edge of North America and the Atlantic Ocean and the later evolution of this continental margin by landslides and other active processes. A record of these geological events is stored in the rocks offshore North Carolina. We will collect active and passive, onshore and offshore seismic data to image geological structures at a range of scales to learn about the evolution of continental margins and their geohazards.

  • Greenland’s ice sheets are shrinking faster than ever, responsible for about a quarter of sea-level rise globally. Alison Glacier on Greenland’s northwestern coast is one place where ice flow to the sea has speeded up. From a tiny hunting and fishing village in the Upernavik Islands, scientists from Columbia University's Lamont-Doherty Earth Observatory will take ocean measurements to understand why Alison is surging to the sea faster than nearby glaciers. They will also work with villagers to continue data collection when they’re gone.

  • Many tropical mountains have the same shape—steep, rugged slopes capped by wide, flat summits. Were these landscapes shaped by tectonic forces from below? Or by intense glacial erosion from above? Graduate student Maxwell Cunningham and scientist Mike Kaplan are collecting glacial debris from Costa Rica’s 12,000-foot Cerro Chirripó to test their idea that mountain glaciers carved Chirripó’s peak into the shape we see today, similar to beveled summits in Taiwan, Papua New Guinea and Uganda.

  • 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. We will collect seismic refraction data, which can be used to image structures in the crust to understand these tectonic events. During March 2014, over 1000 geophones will be deployed along a ~300-km-long profile across the suture and the basin, which will record sound waves generated by a series of controlled blasts spaced ~20 km apart. The speed that sound waves travel through rocks varies with rock type. We will use these data 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.

  • The South China Sea is one of the most geopolitically contested marine realms on earth. But it is also of keen interest to geologists who want to understand how this ocean basin, bordered by China, the Philippines, Malaysia and Vietnam, opened up. On an International Ocean Discovery Program cruise aboard the JOIDES Resolution, scientists will drill through seafloor sediments to understand how the basin reached its present form. Marine geologist Trevor Williams of Lamont-Doherty Earth Observatory is directing downhole logging operations. Follow his dispatches from the ship here.