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What are examples and properties of Lithogenous sediments
- Eroded rock fragments from land
- Reflect composition of rock from which derived
- Most lithogenous sediments at continental margins
- Coarser sediments closer to shore
- Finer sediments farther from shore
- Mainly mineral quartz (SiO2)
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How are Neritic sediments distributed and in which regions are they normally found?
- Shallow water deposits
- Close to land
- Dominantly lithogenous
- Typically depositedquickly
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What are som Types of neritic lithogenous sediments
- Beach deposits
- Mainly wave-depositedquartz-rich sands
- Continental shelf deposits
- Relict sediments
- Turbidite deposits
- from turbidity currrents
- Glacial deposits
- High latitude continental shelf
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How are Pelagic sediments distributed and in which regions are they normally found?
- Deeper water deposits
- Finer-grained sediments
- Deposited slowly
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What are the most common sources of fine pelagic lithogenous sediments?
- Volcanic ash (volcanic eruptions)
- Wind-blown dust
- Fine-grained material transported by deep ocean currents
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what are the main qualities of Abyssal clay (red clay) and how are they transported?
- At least 70% of clay-sizedgrains from continents
- Transported by winds andcurrents
- Oxidized iron
- Abundant if other sediments absent
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What are examples of Biogenous marine sediments and of what two organisms are they mainly of?
- Hard remains of once-livingorganisms
- Shells, bones, teeth
- Macroscopic (large remains)
- Microscopic (small remains)
- Tiny shells or tests settlethrough water column
- Biogenic ooze (30% or moretests)
- Mainly algae and protozoans
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What are two examples of Silica in Biogenous sediments and what type of ooze do they produce?
- Diatoms (algae)
- Radiolarians (protozoans)
- (Produces Siliceous Ooze).
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What are they main properties of Siliceous Ooze?
- Seawater undersaturated with silica socontinually dissolves back into water
- Siliceous ooze commonly associated with highbiologic productivity in surface ocean becauseonce buried, they don’t dissolve easily
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Give examples of Calcium carbonate in biogenous sediments (2 organisms)
- Coccolithophores
- Foraminifera(protozoans)
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What properties describe Foraminifera(protozoans) and what type of ooze do they produce?
- Use external food
- Calcareous ooze
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What are some characteristics of Coccolithophores(algae)?
- Photosynthetic
- Coccoliths (nanoplankton)
- Rock chalk
- May use plates assunshades
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What factors control the distribution of biogenous sediments?
- Productivity
- Destruction (dissolution)
- Dilution
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Give examples of Carbonate deposits (2 examples)
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Describe the properties Limestone.
- Lithified carbonatesediments
- White Cliffs of Dover, England ishardened coccolithophore ooze
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What environment do Stromatolites experience and of what bacteria were they originated?
- Warm, shallow ocean, high salinity
- Cyanobacteria
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Calcareous ooze and the CCD? Describe warm water, shallow ocean and cool, deep oceans with respect to their saturation of calcium carbonate(s).
- Warm, shallow ocean saturatedwith calcium carbonate
- Cool, deep ocean undersaturatedwith calcium carbonate
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Lysocline
depth at which asignificant amount of CaCO3 beginsto dissolve rapidly
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Calcite compensation depth (CCD) At what 'cline?
- Below lysocline, depth where CaCO3readily dissolves
- little calcareous ooze
- Rate of supply = rate at which the shellsdissolve
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Minerals precipitate directly from seawater (Hydrogenous) Give examples (At least 4)
- Manganese nodules
- Phosphates
- Carbonates
- Metal sulfides
- Small proportion of marine sediments
- Distributed in diverse environments
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Describe characteristics of Phosphates, it's use and describe the areas it would most likely to be found.
- Phosphorus-bearing apatite sedimentary rock
- Occur beneath areas in surface ocean of veryhigh biological productivity
- phosphatesreleased into interstitial water by decomposition
- Economically useful: fertilizer
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Give examples of Carbonates (CaCO3) (At least 3)
- Aragonite and calcite
- Oolites
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Give examples of Cosmogenous marine sediments (At least 2)
- Macroscopic meteordebris
- Microscopic iron-nickel and silicate spherules
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Give examples of Microscopic iron-nickel and silicate spherules (2 examples)
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Usually mixture ofdifferent sediment types contain up to how much non-biogenic components?
biogenicoozes can contain up to 70% non-biogeniccomponents
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Neritic sediments cover about _ of sea floor
¼
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Pelagic sediments cover about _ of sea floor
¾
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Distribution of neritic and pelagic marinesediments controlled by:
- Proximity to sources of lithogenous sediments
- Productivity of microscopic marine organisms
- Depth of water
- Sea floor features
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How sea floor sediments represent surface ocean conditions
- Microscopic tests sink slowlyfrom surface ocean to sea floor(10-50 years)
- Tests could be movedhorizontally
- Most biogenous tests clumptogether in fecal pellets
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Marine sediments often representocean surface conditions preservesrecord of past
- Temperature
- Nutrient supply
- Abundance of marine life
- Atmospheric winds
- Ocean current patterns
- Volcanic eruptions
- Major extinction events
- Changes in climate
- Movement of tectonic plates
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How do researchers traditionally retrieve sediments?
- Dredge
- Gravity corer
- Rotary drilling
- Deep Sea Drilling Program
- Ocean Drilling Program
- Integrated Ocean Drilling Program
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Studies reveal support for which theories about the ocean?:
- plate tectonics
- drying of the Mediterranean Sea
- global climate change
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