Essentials of Oceanography Chap 4 Flashcards
How do deep ocean basin sediments form
suspension settling leads to fine particles sinking to the bottom of the ocean
What is ocean basin sediment connection to sedimentary rock on land
A lot of the sedimentary rock on land was formed by suspension settling in ocean basins and later uplift.
What is north atlantic deep water circulation
North Atlantic Ocean, cold, relatively salty water sinks, which circulates through the global ocean, driving deep-ocean circulation and global
heat transport
what mineral is the main composer of lithogenous sediment
Quartz
2 types of marine deposits
neritic and pelagic
what are neritic deposits
Near coast deposits on continental shelves and in shallow waters. Usually coarse grained due to high energy.
What are pelagic deposits
Deep-Ocean basin deposits, fine sediments due to low energy.
Why are a lot of continental shelf deposits only composed of sediment from 3-7 thousand years ago
10,000 years ago, after the glaciers melted, river mouths were drowned and led to less sediment transported to the ocean as the sediment would be dropped at these drowned river mouths.
What are biogenous marine deposits
rock formed of the hard parts of marine organisms
What is biogenous ooze
fine grained, soft biogenous deposit
2 most common chemical compounds in biogenous ooze
Silica and calcium carbonate.
What are the organisms that form biogenous ooze
Algae(marine plants) and Protozoans( marine animals)
What organisms form silica in biogenous ooze
diatoms(algae) and radiolarians(protozoan)
What is diatomaceous earth
when diatom rich ooze lithifies, it forms into a white soft rock
What is siliceous ooze
ooze primarily formed of diatoms and radiolarians
2 organisms that form calcareous ooze
foraminifers(protozoan) and coccolithophores(algae)
What does coccolith rich calcareous ooze often lithify into
Chalk
How large are coccoliths
extremely small
Where does most carbonate and calcareous ooze deposits form
shallow waters
What happens to most silica in the ocean
Dissolves in ocean water
How does siliceous ooze form
areas of high biological activity of silica-secreting organisms. This is because if only a small amount of silica-secreting organisms sinks to the sea floor, it will constantly get dissolved.
where does calcite dissolve in oceans
Deeper waters, as colder water contains more carbon dioxide. Furthermore, higher pressure speeds up the dissolution of calcite.
What is the lysocline
depth at which the rate of dissolution of calcite begins to increase dramatically.
Do calcite secreting organisms live in cold or warm water
warm water
Do silica-secreting organisms live in cold or warm water
cold water.
What structure do calcareous ooze like to form around
Mid-ocean ridges to do increased elevation on the crest and warm waters due to the mid-ocean ridge
What mechanism leads to increase in silica-secreting organisms locally
upwelling, as cold, nutrient dense water rises.
What is hydrogenous sediment
sediment derived from dissolved material precipitating from water
when does precipitation occur
change in conditions, such as a change in temperature or pressure or the addition of chemically active fluids.
What is cosmogenous sediment
extraterrestrial sediment
2 main types of cosmogenous sediment
spherules and meteor debris
How thick is the layer of sediment in mid-ocean ridges
thin. the older the sea floor, the thicker the layer of sediment
