Oceanography Study Guide Flashcards

Terms Definitions
Continental-Continental Convergent Plate Boundary
long, narrow, steep-sided depression in the seafloor formed where one crustal plate sinks beneath another
Frozen part of the hydrosphere
Taypes of Water Changes
Evaporation -
• LithosphericPlates descend into mantle
• Destroysoceanic crust
Near shore lithogeneous deposits
Neritic Deposits
Are transform faults perpendicular or parallel to the aces of mid-ocean ridges?
ocean in which continental shelves take up more space (wider)
What causes the plates to move?
Calcareous Organisms
• Makeshellsoutof CaCO3 (calcium carbonate)
• Foraminifera – Single cells
• Coccolithophore – single-celled algae – photosynthetic
What is this an image of?
What happens to water depth?
Depth increases
Where do you find older seafloor rocks?
the movement of deep, cold, and nutrient-rich water to the surface
white capped waves that crash into shore before they become breakers there called swells that are low and long.
White Cliffs of Dover- formed from rock (rock type is chalk) made of calcareous ooze
Abbreviation for the depth at which calcium carbonate dissolves
What is the driving force of movement?
Pelagic sediments
Pelagic sediments, also known as marine sediments, are those that accumulate in the abyssal plain of the deep ocean, far away from terrestrial sources that provide terrigenous sediments; the latter are primarily limited to the continental shelf, and at some point were probably deposited by rivers.[1] Pelagic sediments that are mixed with terrigenous sediments are known as hemipelagic.

There are three main types of pelagic sediments:[2]
1. Siliceous oozes
2. Calcareous oozes
3. Red clays
Many of the unique properties of water are attributed to the fact that water is what type of molecule?
What type of plate boundary has the most earthquakes?
the area where a freshwater stream or river merges with the ocean (brackish)
bottomost of the wave or the space inbetween two crests.
sonar is a system of imaging which uses sound to send out a wave then it calculates the time when the wave is emmited to the time it is has been recived to create an image., a measuring instrument that sends out an acoustic pulse in water and measures distances in terms of the time for the echo of the pulse to return
When pieces of the glacier breaks off, forms icebergs
Lithogenous = broken bits of rock (the term "terrigenous" is often used interchangably with "lithogenous")
- Sediment layers are thickest near the continents, the source of lithogenous material, and thinner farther out to sea. - If you determine that the seds are lithogenous, next check grain size: are they fine, medium or coarse?
Sediments are coarsest near the continental source: the farther from the source, the finer the sediments. - Land areas highest above sea level have the fastest erosion, and the sea floor near mountains will have the most rapid sediment accumulation. - Running water is the main delivery mechanism.
Wet climates have fast erosion on land, and rapid sediment deposition in nearby oceans. Arid regions have slower sedimentation rates.
• Turbidites are sediments deposited by underwater landslides (turbidity currents), caused by earthquakes or over-loading of the seds on continental shelf. The seds are sorted out as they flow, and settle in a regular pattern: the coarses particles settle first, then medium, then fine. Repeated sequences of this graded bedding indicates that an are has had many underwater landslides.
• Volcanic ash is produced by violent volcanic eruptions. Ash then settles out of the atmosmosphere, through the ocean, and contributes to the sediment column. Where would this type of violent eruption occur?
• Red Clays and Brown Muds are very fine-grained, thin sediments found on the abyssal plains, where there isn't much contributing to the sediment column. These are the finest lithogenous particles from the continents, carried a long distance out to sea before settling out.
Origin of hydrogenous sediment
• Hydrogenous sediment forms when dissolved materials come out of solution (precipitate)
• Precipitation is caused by a change in conditions including:
– Changes in temperature
– Changes in pressure
– Addition of chemically active fluids
Part of Earth made up of living organisms
Examples of a Hot Spot
H- Hawaii Y- Yellowstone
• Fan shaped deposit formed when a stream enters the ocean and drops all of its sediment
An example of continental-continental convergent plate boundary
St Andreas Fault
Where does the new lithosphere form in the ocean?
mid-ocean ridges
What processes could decrease seawater salinity?
Precipitation, Runoff, Icebergs melting, Sea ice melting
Is the pH of the ocean slightly acidic or alkaline?
plants and animals living on or in the seafloor
neap tide
formed when the sun, earth, and moon form a 90 degree angle
mid-ocean ridge
a range of under water mountains that winds around the globe.
Convergent boundaries.
Plates may converge directly or at an angle. Three types of convergent boundaries are recognized:
• continent-continent
• ocean-continent
• ocean-ocean.
What is this an example of?
An active continental margin
Evidence for Continental Drift
1. ContinentalFit
2. Fossils
3. LinearMountainRanges
Distribution of biogenous ooze
• Most biogenous ooze found as pelagic deposits
• Factors affecting the distribution of biogenous ooze:
– Productivity (amount of organisms in surface waters)
– Destruction (dissolving at depth)
– Dilution (mixing with lithogenous clays)
What is an abyssal plain?
A flat depositional surface extending seaward from the continental rise or oceanic trenches.
What is hydrologic cycle?
Relates to the process that affects seawater salinity. Recycle water among the ocean, the atmosphere, and the continents, so water is in continual motion between the different components of the hydrologic cycle.
ocean basin
low area on earth in which an ocean formed when the area filled with water from rain
Transform Plate Boundary
The type of boundary hwere two plates slide past eachother
What is the depth if the pressure is equal to 24.5 kg/cm3?
245 m
Do hydrothermal vents have a significant impact on ocean chemistry?
Yes. Vents discharge hydrogen sulfide gas.
high salinity, cold temperature
____ and ____ describe the most dense water in the ocean
In an Oceanic-Continental Convergent plate boundary, which plate is denser? Why is it denser?
Oceanic is denser because of the amount of iron and magnesium
What are the differences between hydrosphere, cryosphere atmosphere, geosphere, lithosphere and biosphere?
Hydrosphere: includes water in solid liquid, and gas forms
Cryosphere: the frozen part of the hydrosphere
Atmosphere: gasses and suspended particles surrounding the planet
Geosphere: Solid - rocks, minerals and sediments
Lithosphere: composed of uppermost mantle and crust divided into riged plates that move and interact
Biosphere: all living organisms
What is methane hydrate?
A solid form of methane bonded with water
Provide four pieces of evidence that support continental drift
The fitting of the continents, Matching sequences of rocks and mountain chains, glacial ages and other climate evidence and distribution of organisms
How does the continental shelf, slope, and rise differ between tectonically active and tectonically passivly continental margins?
• Active - Narrow continental shelpf, steep continental slope, trench instead of continental rise.
• Passive - wide, flat continental shelf, gentle continental slope, continental rise
SUMMARY -- Distribution of sediment on the sea floor (modern sediments)
Terrigenous: - - continental margins and adjacent abyssal plains.
Manganese nodules: - - deep basins, especially the Pacific.
Red Clay: - - deep ocean regions where not diluted by biogenic particles.
Calcareous oozes: - - wide-spread in relatively shallow areas of the deep sea.
Siliceous oozes: - - polar and equatorial bands where nutrients are supplied to surface waters by vertical upwelling.
How can fossils found in marine sediments provide evidence concerning plate tectonics
The same fossils of certain species have been found in on different continents around the world suggesting that the earth was one landmass at a period of time
Describe global water cycle in terms of evaporation, transpiration, sublimination, condensation, precipitation, deposition, run-off, and infiltration
• evaporation: water - liquid to gas
• transpiration: water - vapor released by plants into atmosphere
• sublimination: water - solid to gas
• condensation: water - gas to liquid
• precipitation: water - rain or snow
• deposition: water gas to solid
• run-off: water - flowing on surface of earth
• infiltration: surface of earth into the ground
Is there any change in the thickness of the lithosphere as one moves from the oceanic ridge towards an oceanic trench?
yes, the lithospheric plates bend and sometimes slope downwards under other plates
Sediments can be classified BY AREA OF DEPOSIT:
Neritic = deposited on the continental shelf
Pelagic = deposited beyond the continental shelf
What is the relationship between the age of the sea floor and sea floor spreading?
As the new rock comes up, then the older rock spreads away along the sea floor
density current
Continental Shelf
Nearly Flat
Cosmogeneous sediment
Marine sediment from space
Marine Sediment from space
Cosmogeneous Sediment
Divergent Plate Boundary
• NewOceancrustis formed
precipitate chemically out of seawater. Ions dissolved in seawater combine to form minerals, which precipitate out as solids • Polymetal Sulfides: abundance of metals and sulfur compounds
- ions dissolved from ocean crust by hot water, precipitate when contact cold water; found at present or past sites of hydrothermal vents
• Manganese Nodules: marble-sized to fist-sized lumps, rich in manganese, copper, nickel and silica precipitated from seawater - form a kind of cobblestone pavement on parts of the abyssal plains; always at the top of the sediment column - form where sediment accumulation rate is very slow: far from continents and plate edges, far from biol. productive zones
• Evaporites: layered deposits of salt - form in arid regions; form when a body of seawater becomes isolated, the water evaporates & leaves behind solid salt deposit
• Phosphorite Nodules: small spherical masses rich in phorphorus
Part 2 of HANDOUT 6
- form on continental shelf mostly, in areas where the concentration of phosphorus in the water exceeds 15%
Are deep-focus earthquakes more common in trenches or along mid-ocean ridges
mixed tide
tide that produces larger tides
Example of a hot spot
French Pyrenees
Examples of silica-secreting microscopic organisms
Siliceous ooze
• Silica-secreting organisms accumulate to form siliceous ooze (>30% siliceous test material)
What is this a picture of?
Oceanic-Continental Convergent
A- Andes Mountans C- Cascades
What current is sediment-laden and flows off of the continental shelf?
Turbidity Current
Is the climate distribution on earth primarily controlled by latitude or longitude?
basic motion of water during the passage of a wave
distance to the bottom, the distance from the top to the bottom.
(1) Direct precipitation (ppt) from sea water
(2) Sediment - sea water reaction

"Salts" = Dissolved ions in sea water

Evaporation of sea water in "restricted" basins
Ppt. of "salts" -- NaCl (halite) and CaSO4.2H2O (gypsum)

Manganese nodules

Nodules and crusts of Mn & Fe oxides (Cu, Co, Ni) in deep ocean and along mid-ocean ridges.
Origin (?) -- source of metals

Sea water
Hydrothermal activity (remember "black smokers")
Are in upwelling zones - single celled
Calcareous Oooze
• 30% calcareous organisms
• found in depths less than 4500 miles
• can be found below depth of 4500 miles if they are burried y another type of sediment before being moved
• Mid-Atlantic ridge can be found limited as limestone Organisms:
- - Foraminifera - single cells
- - Cocolithophore - single celled algae, photosynthetic
• Dissolves n deep water
Collection ocean sediments
• Specially designed ships collect cores by rotary drilling
• Cores allow scientists to analyze ocean sediment
Water can pile up a short distance above a container's rim due to what property?
subduction zone
where one crustal plate sinks beneath another
wave height
increases when a wave reaches shallow water
continental slope
The continintal slope is a steady incline that starts at the top of the continintal shelf and decends down into the abbysal plain.
coriolis effect
The way Earth's rotation makes winds in the Northern Hemisphere curve to the right and winds in the Southern Hemisphere curve to the left.
Solid form of methane found in sediment on continental shelf and slope
Methane Hydrate
Manganese nodules
are oxides of the metals manganese (Mn) and iron (Fe). They also contain minor amounts of copper (Cu), cobalt, (Co), and nickel (Ni).
- Manganese nodules occur as nodules and crusts, primarily in deepest of oceans and near mid-ocean ridges.
- Their origin is controversial. We do not know the source of the metals nor how and why they are concentrated in nodules.
- The metals may be delivered as dissolved species or as sediments from land.
- A more likely origin is volcanic activity and hydrothermal alteration of ocean crust at mid-ocean ridges. Remember the "black smokers?" Much of the suspended particles are Mn and Fe oxides.
Are there earthquakes at divergent plate boundaries? Is there volcanic activity?
• Yes
• Yes
Part of Earth that includes water in solid, liquid, ad gaseous forms
A type of satellite that remains over a fixed point of the Earth.
Submarine Canyons
These are cared into continental slope by turbidity currents
Does evaporation increase or decrease salinity?
Evaporation increases salinity
Part of the earth that includes water as a solid, liquid, and gaseous forms
What are "white smokers?"
Water temperature from 30-350 degrees Celsius emit water that is white,because of the presence of various light-colored compounds, including barium sulfide, through the hydrothermal vent.
In the video "Last Oasis," it was mentioned that so much water is being withdrawn from what River that it often does not reach the sea any longer?
Colorado River
What type of plate boundary would you expect to find andesitic volcanoes
convergent boundary
biological amplification
When really big fish eat small fish and become very unhealthy
The type of boundaries where plates move away from each other
Divergent plate boundaries
Part of the earth made up of living organisms
Lithogeneous Sediment
• Sediment from rocks
• Result of weathering and erosion
Where are the steepest slopes in the ocean found?
The Pacific Ocean
Water is a critical resource. Where is most of the fresh water on earth located?
Polar Ice Caps
semi-diurnal tide
A tidal cycle of two high tides and two low tides each lunar day, with the high tides of nearly equal height.
Sediment Deposit (n mid--ocean locations)
Sediment thickness
• 5c per 1000 years
• .005 er 1,000 years
Where will there be the greatest accumulation of lithogeneous sediments?
Closest to the continents
Oceanic Crust
Part of the earth that is solid, and very dense
In which of Earth’s 4 spheres does sublimation take place?
hydrosphere to atmosphere
Coral Atoll (in French Polynesia)
Rin shaped island surrounding a lagoon, formed on eroding volcano
How did submarine canyons form?
Created on the continental slop by some marine process and enlarge into the continental shelf through time.
How do magnetic anomalies support plate tectonics and seafloor spreading?
Magnetic anomalies record the movement of the plates, the age of the rocks, and the magnetic reversals. They can be used to track the movement
of the plates over the past.
Four Types of Sediment
• There are four basic types of marine sediments, all of which are grouped and ordered by the origin of their particles, the grain sizes, and where they are deposited.
• These four kinds include lithogenous, biogenous, hydrogenous, and cosmogenous. All of these are different from one another in some way but all share in common the tendency to collect along the floor of the oceans as a testament to many natural processes such as weathering, erosion, and collision.
Ice-Rafted Glacial Sediments
Occures mostly on the floor of a polar ocean
The scientists Vine and Matthews determined that new ocean floor was being produced at ocean ridges by examining what evidence from the sea floor?
The unrelated pattern of magnetic sea floor stripes with the process of sea floor spreading
How does an atoll form?
• Step 1: Volcano forms. Reef begins to grow in shallow water on flanks of volcano.
• Step 2: Volcano is extinct and begins to erode. A shallow lagoon separates the volcano from the reef.
• Step 3: Volcano erodes below sea level. The reef may grow until it eventually breaks above the surface.
Features of the Ocean Floor: Abyssal Plains
• Flat, Very Flat areas of sea floor
• Form seaward of continental rise
• Result of Sediment settling out of water and burying any or all topography
• Deep
Why do oceans become deeper moving away from the mid ocean ridges?
Because the sea floor begins to rise as the new rock develops
The earth's continents are constantly moving due to the motions of the tectonic plates. Closely examine the map below, which shows the 15 major tectonic plates.
As you can see, some of the plates contain continents and others are mostly under the ocean. The type of crust that underlies the continents is called continental crust, while the type found under the oceans is called oceanic crust. Continental crust is thicker — about 20 to 40 miles (35 to 70 km) thick — and usually older than oceanic crust, which is only 4 to 6 miles (7 to 10 km) thick. All the plates have names, usually referring to landmasses, oceans, or regions of the globe where they are located.

Tectonic Plates Map

The border between two tectonic plates is called a boundary. All the tectonic plates are constantly moving — very slowly — around the planet, but in many different directions. Some are moving toward each other, some are moving apart, and some are sliding past each other. Because of these differences, tectonic plate boundaries are grouped into three main types.
Why is Edmonton colder in the winter and warmer in the summer?
Edmonton is inland. It does not have the ocean to keep it warm in the winter and cool in the summer. Juneau is on the coast. The ocean absorbs a lot of energy during the summer, then releases that energy in the winter, keeping Juneau warm. It absorbs all the energy in the summer, which keeps Juneau cool.
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