X1014072087-00041-08730</DOCNO> lecture05 Lecture 5 -- Marine Sedimentation Bathymetry of the oceans -- as inferred from satellite gravimetry Topographic profiles -- low aspect ratio (H/L) Main topographic features Distribution of continental shelves Eastern seaboard -- example of changing coastlines, ice-age coastline Continental margin profile shelf (0.001) slope (0.1) rise (0.01) Monterey &amp; Grand Canyons Sediments -- allowing us to look back in time terrigenous sediment (erosion from land, silt, sand, gravel, terrestrial plant matter) neritic deposits (coastal sediments of both terrestrial and sea origins) pelagic deposits (deep sea, away from shore) Continental shelf sedimentation relic sediments associated with glacial deposits Continental shelf formation wave cut terrace with offshore deposition variety of mechanisms for trapping sediments Continental shelf sedimentation -- types &amp; distributions of shelf deposits biogenic -- near the equator, coral reefs and calcium carbonate (CaCO3) relic sediment -- mid-latitude processes no longer active (ancient terrigeneous sediment) terrigenous sediment (mid latitude) glacial marine sediments Ocean basins Trenches Ridge-rise systems Ocean basin floor Stratigraphy of the the Mid-Atlantic Ridge rift valley -- no sediments thin calcareous biogenic ooze red clay at greater depths (below the CCD) Carbonate Compensation Depth -- depth below which carbonates dissolve in seawater CCD varies from place to place -- typically around 4 km, deeper than some mid-ocean ridges pelagic sediments form a relatively thin layer, thinnest near rifting ridge systems basaltic layers underlie sediments different types of basalt (dense black rocks) are distinguished by the nature of their formation basalt forms when mantle (peridotite) rises to lower pressures and temperatures.
(Continental shelf formation wave; cut; terrace; with offshore deposition variety of mechanisms) (mantle; rises; to lower pressures and temperatures) (Grand Canyons Sediments; allowing; us to look back in time) Context(Grand Canyons Sediments allowing,List([401, 436))):(us; to look; back; T:in time) (carbonates; dissolve; depth below which carbonates dissolve in seawater CCD varies from place to place) (basaltic layers; underlie; sediments different types of basalt) (depth below which carbonates dissolve in seawater; varies; from place; to place) (Continental shelf sedimentation relic sediments; associated; with glacial deposits)
Grand Canyons Sediments allowing,List([401, 436))
Continental shelf formation wave mantle Grand Canyons Sediments us carbonates basaltic layers depth below which carbonates dissolve in seawater Continental shelf sedimentation relic sediments
cut rises allowing to look dissolve underlie varies associated
terrace with offshore deposition variety of mechanisms
to lower pressures and temperatures
us to look back in time
back T:in time
depth below which carbonates dissolve in seawater CCD varies from place to place
sediments different types of basalt
from place to place
with glacial deposits