Characteristics of Biogenous Sediment

Calcareous ooze

Deposits comprised primarily of tests of foraminifers, coccolith a and other calcareous-secreting organisms

Radiolarians

(A spoke of Ray) -microscopic single-felled pritozons -planktonic -often have long spikes or rays of silica protruding their siliceous shells -do not photosynthesize -have well developed symmetry

Foraminifers

(An opening) -single-called protozons -planktonic -micro/macroscopic -do not photosynthesize -produce hard calcium carbonate test in which the organism lives in

Coccolithophores

(Berry stone carrying) -microscopic algae -single-felled algae -planktonic -produce thin plates or shields made of calcium carbonate -photosynthesize -often call nonnoplankton (dwarf wandering) because they are tiny

Diatoms

(Cut in half) -photosynthesize -free-floating (planktonic) -builds a glass greenhouse out of silica as a protective covering -when diatom-rich ooze lithified it becomes diatomaceous earth

Biogenous sediment

(To produce life) Derived from the remains of hard parts of once-living organisms (shells, bones and teeth)

Chalk

When coccolith-rich ooze lithifies

Ooze

-Microscopic tests that accumulate on the ocean floor and create deposits -very fine-grained mushy material -like toothpaste (mixed half and half with water)

Destruction

-When skeletal remains(test) dissolve in seawater depth

Protozons

-large group of single-celled -eukaryotic -usually microscopic -generally not photosynthetic

Silica

-most come from microscopic algae called diatoms and radiolarians

Productivity

-number of organisms present in the surface water above the ocean floor -surface waters with high biologic productivity contain many living and reproducing organisms(vice versa)

Algae

-primarily aquatic -Eukaryotic -microscopic single cells to giant organisms(ex. Kelp)

Dilution

-when the deposition of other sediments decreases the percentage of the Biogenous sediment found in marine deposits -occurs most often because of the abundance of coarse-grained Lithogenous material in Neritic environments

Distribution of Biogenous sediment on the ocean floor depends of 3 fundamental processes

1. Productivity 2. Destruction 3. Dilution

Siliceous ooze

Accumulation of siliceous tests of diatoms, radiolarians and other silica secreting organisms

Organisms that contribute to Biogenous sediment are

Algae and protozons

Microscopic Biogenous sediment

Contains particles so small they can only be seen well through a microscope -microscopic organisms produce tiny tests that sink to the ocean floor when organisms die

Two significant sources calcium carbonate Biogenous ooze are

Foraminifers and coccolithophores

Macroscopic Biogenous sediment

Large enough to be seen without the aid of a microscope -includes shells, bones and teeth of large organisms -relatively rare except in certain tropical beach localties

Biogenous sediment is one of the most common types of...

Pelagic deposits

Coccoliths

Plates that disaggregate and occur late on the ocean floor as coccolith-rich ooze, when organisms dies

Tests

Shell

Diatomaceous earth

A lightweight white rock composed of diatom test and clag

Two most common chemical compounds in Biogenous sediment are...

Calcium carbonate and silica