MAR 354 05- Marine Sediments
What is hydrogenous sediment?
derived from water examples: manganese nodules, oolites where is it found? -abyssal plains - continental shelf
what is the largest terrrestrial source?
terrigenous sediments
What are hydrothermal vents?
- an opening in the sea floor out of which heated mineral-rich water flows. -rich in Fe, Mn, Cu -strongly associated with fast spreading ridges
Why are marine sediments important?
- habitat for organisms -play a role in climate change - contain history of life
authigenic sediment
- sediment formed by hydrothermal vent sediments - manganese nodules -ooids
What is cosmogenic sediments?
- very small percentage of sediments - glassy tektites
What are the four types of sediments?
1. Terrigenous 2. Biogenic 3. Hydrogeneous 4. Cosmogenic
how do we sample marine sediment?
1. box and multi cores 2. gravity cores 3. piston cores 4. drilling
What are the two types of bio oozes?
1. carbonate oozes 2. siliceous oozes
What is the order of sediment size?
1. clay 2. silt 3. sand
going from shore to deep ocean what are the types of sediments you see?
1. sand 2. silt 3. clay 4. coral limestone 5. oozes
What is the order of long it takes for sediment to settle ( least to most)
1. sand 2. silt 3. clay
How much of the ocean does Silicious oozes cover?
10% - more common at higher altitudes and at tropical latitudes
What does biological ooze consist of?
30% of skeletal remains and the remaining is clay
How much of the ocean does carboonate oozes cover?
50%
what makes the ocean more acidic?
CO2
what is the importance of carbonate sediments?
Carbonate sediments are a way store CO2 and buffer the ocean water
where are manganese nodules found?
Pacific
What is the Carbonate Compensation Depth?
The depth below which carbonate minerals dissolve because of high CO2 concentrations
What is thermohaline circulation?
The large-scale, long-term movement of water between the surface and deep waters of the ocean, driven by differences in temperature and salinity.
Why is there no silicate compensation depth?
The ocean is undersaturated with respect to SiO2
What are turbidity currents?
an underwater current flowing swiftly downslope owing to the weight of sediment it carries.
The White Cliffs of Dover is made of what
coccolithophorids
What are biogenic sediments?
come from the remains of marine organisms
where is terrigenous sediments found?
continental shelves and deep oceans
What are the most widely distributed in the open ocean?
deep sea clays
mangenese nodules
mineral concretions on the sea floor formed of concentric layers of iron and manganese
Whats the CCD in the atlantic?
most of the atlantic sea floor is above the CCD
Whats the CCD in the Pacific?
most of the pacific sea floor is below the CCD
where are Bio sed. found?
on continental shelves you can find Calcareous ooze.
What are marine sediments?
particles of organic or inorganic matter that accumalate in loose uncemented form.
what are examples of terrigenous sediments?
silt , clay, sand,
What is calcareous ooze made of ?
skeletons of 3/4 groups of megafossils - corals -mollusks -bryozoans
What are benthic ecosystems?
the ecological region at the lowest level of a body of water such as an ocean, lake, or stream
What does the age of the water affect the CO2?
the older deep water has accumulated more CO2 because of respiration and this makes the water more acidic.
What is the correlation of silicate sediment?
there is a clear correlation of silicate sediment accumulation and surface prodcutivity
What are terrigenous sediments?
they come from a variety of sources such as rivers, wind, volcanic, glacial
grain size decreases away from the shore
true
