Biogenous sediments are composed of material that plants or animals make, such as shell fragments, coral reefs, and housings of coccolithophores, radiolarians, diatoms, and foraminifera. It comes from the remains of hard parts of organisms that have died. Biogenous sediments are the second most abundant type.
Calcareous and siliceous oozes are the two main types of biogenous sediments. Calcareous oozes come from foraminiferas and coccolithophores, while siliceous oozes come from diatoms and radiolarians. Calcareous oozes are controlled by destruction, above the calcite compensation depth (CCD), and are found at warm, shallow regions of the ocean. CCD is the specific depth below which the rate of calcium carbonate supply is slower than that of dissolution. On the other hand, siliceous oozes are controlled by preservation and found in colder waters where surface activity is high, such as upwelling regions. Upwelling causes surface waters to typically be biologically productive, meaning that nutrient level is high. Oceanographers find them in deep abyssal plains and below the CCD in high latitude regions.
Origin
They usually originate from teeth, bones, or shells from animals such as whales, fish, algae, or protozoans. Biogenous sediment can be microscopic or macroscopic. Macroscopic sediments are large enough for them to be visible by the naked eye, and they are usually rare except in places such as tropical beaches, where shells and coral fragments exist. Furthermore, microscopic sediment has tiny particles, and the microscopic organisms produce tests, which are tiny shells. Biogenous sediment involves plankton, which are single-celled marine organisms, influencing the growth of skeletal material. After the organisms die, their skeletal remains sink to the deep ocean floor as fecal pellets. Also, biogenic oozes lithify over time into layers of oceanic sedimentary rock.
Composition
Chemical compounds in biogenous sediment come from silica (SiO2) and calcium carbonate (CaCO3). Microscopic algae such as diatoms and protozoans called radiolarians produce most of the silica in biogenous ooze. Radiolarians, planktonic and microscopic single-celled protozoans, possess long rays or spikes of silica that stick out from their siliceous shell.
Foraminifers and coccolithophores produce calcium carbonate biogenous ooze, and when they die, they make coccolith-rich ooze, which forms chalk. Calcareous ooze comes from their tests.
Distribution
Biogenous sediment is a typical pelagic deposit. Productivity, destruction, and dilution determine how they are distributed on the ocean floor. Productivity has to do with the number of organisms that can be found in the surface waters. Surface waters with high biological productivity support many organisms and produce greater amounts of biogenous sediments. Destruction takes place when tests dissolve in seawater at depth, and sometimes, this process occurs before the sediment reaches the sea floor. Dilution occurs when the deposition of other sediments decreases the overall percentage of the biogenous sediment in marine deposits.
Calcareous and siliceous oozes are the two main types of biogenous sediments. Calcareous oozes come from foraminiferas and coccolithophores, while siliceous oozes come from diatoms and radiolarians. Calcareous oozes are controlled by destruction, above the calcite compensation depth (CCD), and are found at warm, shallow regions of the ocean. CCD is the specific depth below which the rate of calcium carbonate supply is slower than that of dissolution. On the other hand, siliceous oozes are controlled by preservation and found in colder waters where surface activity is high, such as upwelling regions. Upwelling causes surface waters to typically be biologically productive, meaning that nutrient level is high. Oceanographers find them in deep abyssal plains and below the CCD in high latitude regions.
Origin
They usually originate from teeth, bones, or shells from animals such as whales, fish, algae, or protozoans. Biogenous sediment can be microscopic or macroscopic. Macroscopic sediments are large enough for them to be visible by the naked eye, and they are usually rare except in places such as tropical beaches, where shells and coral fragments exist. Furthermore, microscopic sediment has tiny particles, and the microscopic organisms produce tests, which are tiny shells. Biogenous sediment involves plankton, which are single-celled marine organisms, influencing the growth of skeletal material. After the organisms die, their skeletal remains sink to the deep ocean floor as fecal pellets. Also, biogenic oozes lithify over time into layers of oceanic sedimentary rock.
Composition
Chemical compounds in biogenous sediment come from silica (SiO2) and calcium carbonate (CaCO3). Microscopic algae such as diatoms and protozoans called radiolarians produce most of the silica in biogenous ooze. Radiolarians, planktonic and microscopic single-celled protozoans, possess long rays or spikes of silica that stick out from their siliceous shell.
Foraminifers and coccolithophores produce calcium carbonate biogenous ooze, and when they die, they make coccolith-rich ooze, which forms chalk. Calcareous ooze comes from their tests.
Distribution
Biogenous sediment is a typical pelagic deposit. Productivity, destruction, and dilution determine how they are distributed on the ocean floor. Productivity has to do with the number of organisms that can be found in the surface waters. Surface waters with high biological productivity support many organisms and produce greater amounts of biogenous sediments. Destruction takes place when tests dissolve in seawater at depth, and sometimes, this process occurs before the sediment reaches the sea floor. Dilution occurs when the deposition of other sediments decreases the overall percentage of the biogenous sediment in marine deposits.