sediments Flashcards
what is sediment
Particles of organic or inorganic matter that accumulate in a loose, unconsolidated form
where is the least amount of sediment
at the ridges (youngest part of the ocean basin)
3 things that seafloor features provide
- Habitat
- Food source
- Historical records of past processes
how is sediment usually sorted
by size as its transported - smaller particles are easier to transport
2 ways sediment is classified
size + source
how is sediment classified by size
- Clay, silt, sand, pebbles, cobbles, boulders
how is sediment classified by source
Terrigenous sediments
Biogenous sediments
Hydrogenous sediments
Cosmogenous sediments
what are Terrigenous sediments
Erosion of land, volcanic eruptions, blown dust
*most abundant (amount)
what are Biogenous sediments
Organic; accumulation of hard parts of some marine organisms
*Most abundant proportion
what are Hydrogenous sediments
Precipitation (stuff from the sky e.g. rain) of dissolved minerals from water, often by bacteria
what are Cosmogenous sediments
Dust from space, meteorite debris
what is Neritic
Of the continental shelf - primarily terrigenous sediments
what is Turbidites
Deposited by turbidity currents
what is Ooze
- Deep-ocean sediment containing at least 30% biogenous material
what are the 2 kinds of ooze
- Siliceous ooze – silica rich
*predominates at greater depths + colder polar regions - Calcareous ooze - contains calcium - forms mainly in the shells of foraminifera, pteropods, and tiny algae called coccolithophores
*does not accumulate below the CCD (certain depth) - water contains more CO2 -> more acidic - shells dissolve and so do not accumulate
what is marine snow
Undersea peaks that imitate terrestrial mountain ranges
2 things used to sample sediment
Clamshell Sampler
Piston Corer
