In geology, a graded bed is one characterized by coarse sediments at its base, which grade upward into progressively finer ones. Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of Graded beds generally represent depositional environments which decrease in transport energy as time passes, but also form during rapid depositional events. They are perhaps best represented in turbidite strata, where they indicate a sudden strong current that deposits heavy, coarse sediments first, with finer ones following as the current weakens. Turbidite Geological formations have their origins in Turbidity current deposits, which are deposits from a form of underwater Avalanche that In Geology and related fields a stratum (plural strata) is a layer of rock or Soil with internally consistent characteristics that distinguishes They can also form in terrestrial stream deposits. "Riverine" redirects here For the use of that term in Maritime geography, see there
References
- Monroe, James S. , and Reed Wicander. The Changing Earth: Exploring Geology and Evolution, 2nd ed. Belmont: West Publishing Company, 1997. ISBN 0-314-09577-2 pp. 114.