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Sea Sediments. Match the type with origins Cosmogenous 1. dissolved elements Hydrogenous 2. erosion Biogenous 3. dust from space Terrogenous or 4. shells Lithogenous. Cosmogenous: cosmic dust Hydrogenous: dissolved elements such as the manganese nodules with lots of iron.
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Sea Sediments Match the type with origins Cosmogenous 1. dissolved elements Hydrogenous 2. erosion Biogenous 3. dust from space Terrogenous or 4. shells Lithogenous
Cosmogenous: cosmic dust • Hydrogenous: dissolved elements such as the manganese nodules with lots of iron. • Terrogenous/lithogenous: erosion of soil • Biogenous: shells / living organisms
Sediment size from large to small • Silt + clay = mud
Ooze distribution: yellow and green are silaceous (calcium has dissolved due to pressure and cold)
Definitions • Ooze: layer of dead organisms made from biogenous sediment • Carbonate compensation depth (CCD) is a level in the oceans below which the rate of supply of calcium carbonate equals the rate of dissolution, such that no calcium carbonate is preserved.
LYSOCLINE/CCD: calcium carbonate compensation depth LYSOCLINE- RAPID CHANGE IN THE CALCIUM LEVELS AT DEPTHS OF ABOUT 4000-5000 METERS
Sediment on continental shelves • Calcareous biogenous sediments dominate tropical shelves. • River-supplied sands and muds dominate temperate shelves. • Glacial till and ice-rafted sediments dominate polar shelves.
Biogenous sediment producers • Cocolithophores: Ca • Foraminferans: Ca • Diatoms: Si • Radiolarians: Si
Ekman Grab • Ekman Grab for soft • Bottom sampling
Hydrogenous sediments • Ferromanganese Nodules • Hydrogenous deposits from as a result of chemical reactions within seawater or between seawater and sediments; most known example are manganese nodules, with „growth rates“ of 5-10 mm/million yr. • Mined for world’s manganese supply.
Glomar Challenger • 1968 - The Glomar Challenger starts operations for the Deep-Sea Drilling Project. Over the years the OPD (Ocean Drilling Project) has drilled many sites. • First major exploration of ocean floor sediments