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Unformatted text preview: 2/12/12! Point Source of sediment Pre-Katrina Which rivers? How much sediment? END Tuesday, January 31, 2012 DELTA SHAPES:
Sediment Supply Versus Energy of removal Grain Size: coastal / nearshore (sand,silt) suspended (fine - silt, clay) organisms / filtering 1! 2/12/12! Names and time to settle Meters of sediment neritic pelagic Is there a reason for this shape? possibilities most related to sea level 2! 2/12/12! 125,000 years ago! elevated intertidal sand shoals! lagoon sediments! elevated beach sequences! elevated coral reefs ! Fluctuations of sea level (-100 m to +5 m) Shoreline position ?
Lowstand sediment at shelf edge. Highstand sediment on continent
bank-margin caves! coral reefs ! The gross structure of climate change and sealevel fluctuations - we know.! 3! 2/12/12! Process of sediment transport Turbidity flow Continental Rise: - - mostly sediment sloughed from the shelf Turbidity currents, canyons, slumps, 4! 2/12/12! 5! 2/12/12! 1929 GLACIERS 6! 2/12/12! WIND-BLOWN (EOLIAN) Spain / Portugal Africa VOLCANIC DUST (ASH) "RED CLAY" 7! 2/12/12! Summary: Terrigenous material to the ocean: How does it get there? Biogenic sediment records: Climate change Currents Ocean chemistry etc. Vertical sequence (cores): changes over time Biogenic Sediments
!! Calcite (CaCO3 ) !Foraminifera ("animals") !Coccoliths (plants) !Pteropods (molluscs - aragonite) !! Siliceous (SiO2 ) !Radiolarians (animals) !Diatoms (plants) FORAMS
Calcite (CaCO3 ) planktonic 8! 2/12/12! COCCOLITH (calcite, algae) Coccolith plates 9! 2/12/12! Biogenic Sediments
!! Calcite (CaCO3 ) !Foraminifera ("animals") !Coccoliths (plants) !Pteropods (molluscs - aragonite) !! Siliceous (SiO2 ) !Radiolarians (animals) !Diatoms (plants) diatoms have shells made of SiO2 (opal-like material - may change to quartz) Radiolarians (shells of SiO2 ) Diatoms 10! 2/12/12! " Red Clay " Nodules are basically oval spherical. Appear to have formed by layers, coatings, laminations.
Manganese Nodules (not only Mn, also Fe, Co, other metals) 11! 2/12/12! COSMIC SPHERULES END 2012 February 02 12! ...
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This note was uploaded on 02/15/2012 for the course GLG 244 taught by Professor Sikorski during the Spring '05 term at Miami University.
- Spring '05