L20 Sediments entering the ocean

L20 Sediments entering the ocean - Geol 107 L20 3 Sediment...

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Geol 107 L20 10/10/2011 1 Sediments entering the oceans Erosion Erosion is the process of removing unconsolidated Earth material and transporting it to other depositional sites (mainly the oceans) Transported by: Wind Water Ice Gravity Wind Erosion Dust storm off Sahara (MODIS 2004) Water Erosion Glacial Erosion Glacier moving down a glacial valley into a fjord, Glacier Bay, Alaska, USA. Note the median and lateral moraines and some icebergs in the bay. Gravity
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Geol 107 L20 10/10/2011 2 River supply to the ocean millions of tons per year Sediments entering the Oceans Sediments and Humans http://instaar.colorado.edu/deltaforce/startpages/margins.html Human activities have resulted in greater rates of erosion and more sediment carried by rivers…… yet Human activities result in 15-30% drop in sediment load carried by rivers to the ocean----why?
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Unformatted text preview: Geol 107 L20 10/10/2011 3 Sediment sediment gravel sand silt clay rock conglomerate sandstone shale siltstone Sediment Behavior • Large (coarse) particles • difficult to transport • fall through water quickly • Medium particle Medium particles • easier to transport • fall slower • Small (fine) particles • very easy to transport – with current, never touch bottom • fall very slowly It takes more energy to initiate entrainment than to transport particles Low pressure (= net lift) Lift on airfoil How clasts move High pressure Lift on clast prompts “entrainment” How clasts move once entrained Current Ripples One way versus Two Way • Ripples on the seafloor Geol 107 L20 10/10/2011 4 Current Ripples One way versus Two Way Modern Ancient...
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This note was uploaded on 11/21/2011 for the course ECON 404 taught by Professor Carrillo during the Spring '11 term at USC.

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L20 Sediments entering the ocean - Geol 107 L20 3 Sediment...

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