180 likes | 206 Views
Dive into seafloor sediments to uncover lithogenous, biogenous, hydrogenous, and cosmogenous origins, their distribution patterns, and economic value. Discover the secrets hidden beneath the ocean's surface and learn why certain sediments are more abundant near continents than at ocean ridges.
E N D
SEAFLOOR SEDIMENTS Lithogenous Biogenous Hydrogenous Cosmogenous
General patterns • Review shape of typical ocean floor • Lots of sediments near continents • Few sediments at ocean ridges – Why?
Lithogenous (1) • From weathering and erosion of continents • Some relatively close to continental mass • Beach sediments • River sediments • Glacial debris • Graded bedding from turbidity currents
Lithogenous (2) • Some found on abyssal plain • Wind-blown debris • Red clays
Biogenous sediments (1) • Remains of formerly living organisms (shells and reef material) • Silica rich: radiolarians, diatoms • Calcium carbonate rich: • forams, coccolithophores, reefs • carbonate compensation depth
Biogenous (2) • Difficult to accumulate biogenous oozes • Productivity of that area of the ocean • Destruction as “shells” fall to seafloor Additional CCD for carbonate sediments • Dilution by other sediments
Hydrogenous sediments • Evaporites • Manganese nodules • Phosphorite nodules • Metal sulfides
Manganese Nodules
Cosmosgenous sediments TEKTITES • Meteorites • Tektites • Random distribution and relatively insignificant
MAP OF SEDIMENTS IN OCEAN • Student version
Resources from the seafloor • What is accessible? • What is owned by whom? • What is economically valuable?