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21 Cards in this Set
- Front
- Back
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Wave Base
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Depth that wave energy is communicated
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Distribution of sediments
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Age of the underlying crust
Tectonic history of the ocean crust Structural trends in basement rock Nature and location of sediment source Sedimentary processes delivering sediments to sites of deposition |
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Crust cools by
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Convection (hydrothermal circulation)
Conduction - heat transfer along temp gradient |
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Coastal features influencing circulation
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- shallow (frictional influence on h2o mvmt)
- enhanced tidal influence/motion (increased amp./speed) - coastal boundary (obstacle - extreme press. gradients) - density stratification effects (suppresion of turbulence & fluid mixing) - terrestrial influences (runoff, buoyancy currents) |
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Particle inputs terrigenous then biogenic
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- Fluvial
- Coastal - Glacial - Aeolian - Primary production of organic material (POM) - caco3 or silicate |
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factors of settling
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- size
- shape - grain density - seawater density and viscosity |
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Forces acting on sinking particle
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gravity force
buoyant force drag force |
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Nepheloid layer
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A suspension of fine particles maintained by a balance of downward settling and upward turbulent resuspension - well developed in western Atlantic
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Multicorer
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determine sediment heterogeneity
large sample volume, evaluate precision excellent sed/h2o interface preservation |
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grab sampler uses, limits
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recent sediments
sed/h2o interface mapping pollutants calibration studies damage to surface layer, mixing |
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boxcorer
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undisturbed sample volume, subsamples
sed/h2o interface |
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piston corer
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up to 20m of seds
lose interface |
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deep ODP drilling
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- very deep sections
well preserved, continuous |
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deep odp uses
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sediment types, reconstructions
magnetic reconstructions biostratigraphy |
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turbidity current
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powerful type of density current consisting of a mixture of sediment and water of density greater than that of the surrounding water
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sedimentation high stand sed delivery atl. vs. pacific
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sediment delivery on pacific type (narrow) margins directly to slope
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factors controlling global sed thickness
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local particle supply to seafloor
degree of preservation after deposition age of seafloor |
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factors controlling sea level
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- shape of the container (thickness, area of continental crust, influence of mass of water on crust thickness)
- changes in isostacy - volume of water in oceans (inputs, outputs, temp of water) |
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particle aggregation mechanisms
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- brownian motion
- fluid shear - differential settlement - motile organism activity - packing fecal matter - mucous feeding webs - exopolymers |
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factors affecting depositional flux ds/dt
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settling rates
suspended sediment concentration also shear stress ratio of dep:resuspension |
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four processes for coastal circulation
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- heating and cooling
- wind stress - freshwater input - tides |
