Oceanography: Chapter 4 (Marine Sediments) – Flashcards
Unlock all answers in this set
Unlock answersquestion
What do marine sediments consist of?
answer
Eroded particles and fragments of dirt, dust and other debris.
question
Marine sediments have been used to study what?
answer
Past climate, geology, and biology.
question
What do sediments over time turn into?
answer
Rock - found in the world's tallest mountains.
question
What do marine sediments provide?
answer
A variety of important resources.
question
What is the study of how ocean, atmosphere, and land interactions have produced changes in ocean chemistry, circulation, biology, and climate.
answer
Paleoceanography.
question
What five pieces of evidence provide clues of our Earth's history?
answer
1. Marine organism distribution 2. Ocean floor movements 3. Ocean circulation 4. Climate change 5. Global extinction
question
Where would we find clues to the origin of sediments?
answer
Mineral composition and texture (size and shape).
question
Lithogenous
answer
Derived from land (small particles eroded from land; also called terrigenous; produced by weathering.
question
Biogenous
answer
Derived from organisms.
question
Hydrogenous (Authigenic)
answer
Derived from water.
question
Cosmogenous
answer
Derived from outer space.
question
What are the two modern explorations of the ocean?
answer
Cores and Rotary Drilling.
question
Define Cores
answer
Hollow steel tubes collect sediment columns.
question
Define Rotary Drilling
answer
Collects deep ocean sediment cores.
question
How are Lithogenous sediments carried to the ocean?
answer
Streams, wind, glaciers, and gravity.
question
Where is the greatest quantity of Lithogenous material found?
answer
Around continental margins.
question
Where are you more likely to find coarse lithogenous sediments as opposed to fine lithogenous sediments?
answer
Coarser sediments are closer to shore and finer are father away.
question
What is the main ingredient in lithogenous sediments?
answer
Mainly mineral quartz (SiO2).
question
How is grain size classified?
answer
Wentworth scale of grain size.
question
What is one of the most important sediment properties?
answer
Grain size.
question
What are the four types of Neritic Lithogenous Sediments?
answer
1. Beach Deposits 2. Continental Shelf 3. Turbidite Deposits 4. Glacial Deposits
question
What do beach deposits consist of?
answer
Mainly wave-deposited quart-rich sands.
question
What does the continental shelf consist of?
answer
Relict sediment, covering 70% of the world's continental shelf.
question
What are turbidite deposits?
answer
Underwater avalanches; forms submarine canyons; spreads to form "fans"; consists of graded bedding.
question
What are glacial deposits?
answer
Located in high latitude environments (currently forming by ice rafting).
question
What are Pelagic Deposits?
answer
Fine grained material that accumulates slowly on deep ocean floors.
question
Pelagic lithogenous sediments comes from what three things?
answer
1. Volcanic ash (eruptions) 2. Wind blown dust 3. Fine grained material transported by deep ocean currents
question
Why is abyssal clay red?
answer
Oxidized Iron (FE).
question
When is abyssal clay most likely to be abundant?
answer
When other sediments are absent.
question
What are abyssal clays composed of?
answer
At least 70%, fine, clay sized particles from the continents.
question
What do biogenous materials (ooze) consist of?
answer
30% skeletal debris, 70% inorganic mud particles.
question
Macroscopic
answer
Visible to the naked eye (teeth, bones, shells).
question
Microscopic
answer
Seen under a microscope (tiny shells)
question
Biogenous deposits consist of what two Oozes?
answer
Calcareous Oozes (Calcium Carbonate) and Siliceous Oozes (Silica)
question
Calcareous oozes break down into what two divisions?
answer
Foraminifers (animal) and Coccolithophores (plant)
question
Siliceous Oozes break down into what two divisions?
answer
Radiolarians (animal) and Diatoms (plant)
question
Coccolithophores (animal)
answer
Range small to large; ingest organisms for food.
question
Foraminifers (plant)
answer
microscopic algae; photosynthesize; spherical shell; forms chalk when dies.
question
Radiolarians (animal)
answer
glass-like exoskeleton; wide variety of patterns; gathers food through pores.
question
Diatoms
answer
Photosynthesize; require strong sun; nutrients allowed in through pores, and waste out; used in many products.
question
Distribution of sediments depends on what three processes?
answer
1. Productivity 2. Destruction 3. Dilution
question
Where are Neritic deposits found?
answer
Shallow water.
question
Where are Pelagic deposits found?
answer
Deep water.
question
What is CCD?
answer
Calcite Compensation Depth is the point at which all calcite dissolves.
question
What happens to Calcareous oozes in deep water (Pelagic Deposits)?
answer
Destruction varies with depth and temperature of water; depth speeds dissolution; CCD is reached
question
What happens to Silicious oozes in deep water (Pelagic Deposits)?
answer
Silica dissolves slowly at all depths; limited amounts of silica; accumulation in high productivity zones.
question
A change in these two conditions allows for precipitation.
answer
Temperature and pressure
question
What four types of minerals precipitate directly from sea water?
answer
1. Manganese Nodules 2. Phosphates 3. Carbonates 4. Metal sulphides
question
Where are phosphates economically useful?
answer
Fertilizers.
question
What are metal sulphides associated with?
answer
Hydrothermal vents and black smokers.
question
Where are hydrothermal vents and black smokers found?
answer
Along the mid-ocean ridge.
question
Metal sulphide deposites contain what 6 things?
answer
1. Iron 2. Nickel 3. Copper 4. Zinc 5. Silver 6. Other materials
question
How are metal sulphide deposits transported?
answer
Sea floor spreading.
question
What are Evaporates?
answer
minerals that form when sea water evaporates.
question
What two minerals are considered evaporates?
answer
Halite (table salt) and Gypsum
question
How is cosmogenous sediment produced?
answer
From materials originating in outer space
question
Where are distributions of Neritic and Pelagic deposits controlled?
answer
1. Proximity to sources of lithogenous sediments 2. Productivity of microscopic marine organisms 3. Depth of water 4. Sea floor features
question
Neritic sediments cover approximately how much of the sea floor?
answer
1/4
question
Pelagic sediments cover approximately how much of the sea floor?
answer
3/4
