Download Sea Floor - Craven County Schools

Sea Floor
Sediments of the Ocean Floor
• Sediment: a gathering of loose material that form
layers
Classified by: size, origin, and chemical
composition.
• Four types of sediment: Lithogenous, Cosmogenous,
Hydrogenous, Biogenous.
Lithogenous
• Derived from rocks at or above sea level that
have been weathered by wind, rain,
freezing/thawing.
• Carried by rivers, wind, gravity, rain runoff, Ice
Glaciers
Cosmogenous
• Derived from small particle of space material
that penetrates the atmosphere.
• Tektites: Spray out of the material formed by
particles
Hydrogenous
• Produced by chemical processes in sea water
• Example: Calcium Carbonates, manganese
nodules
Biogenous
• Derived from once living organisms
A) Calcarous ooze: derived from calcium that
percipitate out of warm water; Calcium is
soluble in cold water.
B) Siliceous ooze: derived from plants &
animals found all over the oceans
1) Diatomaceous ooze: Diatom small singlecelled plants in temperate and polar regions
Sampling methods
• Dredge- large amount. NOT
specific
• Grab Sample- not as large
of a sample. More specific.
Surface of sediment.
• Core Sampler- small
sample. Very specific
• Largest substance mined
from the ocean by U.S. is
sand and gravel.