GEOS126 Lecture Notes - Lecture 9: Continental Shelf, Abyssal Plain, Abyssal Fan
12 Dec 2018
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Lecture 10 - sediments of slope & deep. Sources of sediment to ocean basins: material reworked from shelf areas, supplied directly by rivers, bypassing the shelf, material formed in situ, esp. biogenic material, air-born dust (terrigenous or volcanic, extra-terrestrial (very minor) The blue sections are the mid-oceanic ridges which are new crusts and haven"t had time to accumulate sediment. Stuff can only be moved to the edge of the shelf by waves during periods of continental glaciation. Can also be transported via longshore currents. Can be deposited into a canyon and create a submarine fan. Once at the shelf edge, sediment can move down the slope to be deposited on the rise and abyssal plain. Slop results in distinctive physiographic features and sediment transport pathways. Mixture of solid particles with water, the amount of water changes its behaviour. Gravity causes it to move downhill (requires slope: debris flows. Mainly solid particle and a little bit of water.
