Term
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Definition
| eroded particles and fragments of dirt, dust, and other debris that have settled out of the water and accumulated on the ocean floor. They provide a “map” of the past via core samples to see what the different layers have settled. |
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Definition
| the size and shape of the sediments particles. Measured on the Wentworth scale of grain size the particles can be classified as boulders, cobbles, pebbles, granules, sand, silt, or clay. |
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Definition
| The size of sediment grains based on the Wentworth Scale of Grain Size: Boulders (largest), cobbles, pebbles, granules, sand, silt, or clay (smallest). |
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Definition
| Deposits usually found in the deep-ocean basins and they are typically fine grained. |
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Definition
| deposits are found on continental shelves and in shallow water near islands, they are generally coarse grained. |
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Definition
| a measure of the uniformity of grain sizes and indicates the selectivity of the transportation process. Velocity of the “river” will push the heavier sediments less distance than lighter sediments. |
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Definition
| any sediment deposit that has greater than 30% bio sediment (consistency of toothpaste mixed about half and half with water. |
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Term
| Calcite Compensation Depth |
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Definition
| The depth that the ocean water dissolvers the calcite totally from the sediment. |
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Definition
| The study of how the ocean, atmosphere, and land have interacted to produce changes in ocean chemistry, circulation, biology and climate. |
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Term
| Describe lithogenous sediments |
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Definition
| derived from preexisting rock material that originates on the continents or islands from erosion, volcanic eruptions, or blown dust. The composition is, just like the material it was derived, quartz (same as the Earth’s crust). |
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Term
| Lithogenous Sediment Distributions |
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Definition
Neritic (found on the continental shelves in shallow water near islands and are generally course grained)
Beach Deposits – quartz-rich sand that is washed down to the coast by rivers.
Continental Shelf Deposits – many rivers of the world deposit their sediment in drowned river mouths rather than carry it onto the continental shelf.
Turbidite Deposits – deposited sediment (sea fans) from the turbidity currents.
Glacial Deposits – washed out glacial material that the glacier has picked up as it was moving then deposits when it melts into the oceans.
Pelagic (found in deep-ocean basins and are typically fine grained).
Abyssal Clay – at least 70% fine, clay sized particles from the continents. |
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Term
| Describe biogenous sediments |
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Definition
| derived from the remains of hard parts of once-living organisms. They cover more surface area than any other sediment. |
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Term
| Biogenous Sediment Composition |
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Definition
Composition:
Calcium carbonate – made up of foraminifers and microscopic algae called coccolithophores.
Silica - most silica comes from microscopic algae called diatoms and protozoans called radiolarians.
Nannoplankton.
Distrobution:
Neritic although neritic deposits are dominated by lithogenous sediment, both microscopic and macroscopic biogenous material may be incorporated into lithogenous sediment in neritic deposits.
Carbonate Deposits calcium carbonate deposits are called limestones, they contain fossil marine shells, suggesting a biogenous origin.
Stromatolites a lobate structure consisting of fine layers of carbonate that form in specific warm, shallow-water environments.
Pelagic microscopic biogenous sediment (ooze) is common on the deep-ocean floor because there is so little lithogenous sediment deposited at great distances from the continents that could dilute the biogenous material.
Siliceous Ooze contains at least 30% of the hard remains of silica-secreting organisms. |
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Term
| Describe hydrogenous sediments |
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Definition
| derived from the dissolved material in water. |
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Term
| Hydrogenous Sediment Origin |
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Definition
| Seawater contains many dissolved materials, chemical reactions w/in seawater cause certain minerals to come out of solution, or precipitate. |
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| Hydrogenous sediment Composition and Distribution |
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Definition
Manganese Nodules rounded hard lumps of manganese, iron and other metals typically 5 cm (2 inches) in diameter up to a max of about 20 cm (8 inches). When cut in half, they often reveal a layered structure formed by precipitation around a central nucleation object (like a geode).
Phosphates occur abundantly as coatings on rocks and as nodules on the continental shelf and on banks at depths shallower than 1000 meters (3300 ft).
Carbonates most important carbonate minerals in marine sediment are aragonite and calcite.
Metal sulfides associated with hydrothermal vents and black smokers along the mid-ocean ridge.
Evaporites – form wherever there are high evaporation rates accompanied by restricted open ocean circulation. |
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Term
| Describe cosmogenous sediments |
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Definition
| derived from extraterrestrial sources. |
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Term
| Cosmogenous sediment Origin, Composition and Distribution |
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Definition
forming an insignificant portion of the overall sediment on the ocean floor there are two types of cosmogenous sediment:
Microscopic spherules small globular masses composed of silicate rock material and show evidence of being formed by extraterrestrial impact events on earth.
Macroscopic meteor debris is rare on Earth but can be found associated with meteor impact sites. |
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| Explain which areas of the marine environment have the most & least sediment accumulations |
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Definition
Most sediment accumulations the areas of thick sediment accumulation occur on the continental shelves and rises, especially near the mouths of major rivers.
Least sediment accumulations occur where the ocean floor is young, such as along the crest of the mid-ocean ridge. |
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Term
| Explain the importance of fecal pellets with regards to settling rates of biogenous sediments |
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Definition
| Because 99% of the particles that fall to the ocean floor are part of fecal pellets that are able to sink to the deep-ocean floor in only 10 to 15 days they provide the ability of biogenous tests on the deep-ocean floor closely reflect the population of organisms living in the surface water directly above. |
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Term
| Describe the various resources that are available from the ocean including petroleum, gas hydrates, sand/gravel, salts, phosphorite, & manganese nodules |
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Definition
Energy Resources
Petroleum The ancient remains of microscopic organisms, buried w/in marine sediments before they could decompose. They provide of over 95% of the nonliving resources extracted from the oceans.
Gas Hydrates form only when high pressures squeeze chilled water and gas molecules into an ice like solid, methane hydrates are the most common hydrate in nature.
Other Resources
Sand and Gravel includes rock fragments that are washed out to sea and shells of marine organisms, is mined by offshore barges, this material is primarily used as aggregate in concrete as fill material in grading projects and on recreational beaches.
Evaporative Salts when seawater evaporates, the salts increase in concentration until they can no longer remain dissolved. Gypsum and halite are the most economically useful, gypsum is used in plaster of Paris and Halite is common table salt. |
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