Work on Cores

Deep-sea sediments contain microscopic fossils of marine animals, volcanic glass, sands and minerals originally from land (terrigenous material), cosmic material (microtektites), and other unusual materials unique to a marine environment (such as manganese nodules). The microfossils -- foraminifera, radiolaria, diatoms, etc. -- are important as time and environmental indicators; they are very sensitive to slight changes in temperature and chemical changes in their environment. Volcanic glass is an important "time marker" and records instantaneous geological events. Sands can indicate the presence of ocean currents, tell of ancient shorelines, reveal a past dust storm, or record submarine slides which might indicate submarine earthquakes. Deep-sea samples hold a permanent record of magnetic history revealing to scientists the ever-changing magnetic orientation of the poles.

Climate is one of the main areas of research done on cores today. One way cores can tell a story about climate is by using minerals, volcanic glass, and microfossils that are in the layers of sediment. Find out what four of these cores have told us about climate.

Originally presented at the COLUMBIA UNIVERSITY DISTANCE LEARNING SERIES Earth Science Saturdays at the Lamont-Doherty Earth Observatory.