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185 Cards in this Set
- Front
- Back
how much of the earth is covered by ocean water?
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70 percent
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summarize the big bang
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an all the matter and energy of the universe was packed into one point which exploded.
it took millions of years for conditions to become favorable to where there was the formation of atoms |
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when did the earth form and from what?
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about 4.6 billion years ago from a supernova of a star
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when the did earth's ocean's form? and from what?
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about 4.2 bya from outgassing of the earth's interior
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how is the earth's core is structured?
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The heaviest elements are towards the center and the ligheter elements are towards the outer edge
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what creates the heat at the earth's core
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radioactive decay
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topographic
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depicts height and land surface
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bathymetric
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depicts the depth of the ocean below sea level
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seamount
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underwater volcanoes
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what was the oxygen revolution and who lead it?
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when there was enough oxygen in the air that wasn't being used to oxidize the rocks. Cyanobacteria produced the oxygen
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what is a problem with the mercator projection?
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it distorts distance, shape.
the shortest distance is not between two points is not a line |
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what is good about the mercator projection
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it preserves direction
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what is occurring at the mid atlantic ridge?
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breaking apart and forming of new plates
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where does the most biological productivity occur?
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at the contintental shelf
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hypsographic curve
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demonstrates the high and low points of the land/ocean
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What are the old/new ways that the ocean depth is measured
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Old- rock and string (lead line)
New-Acoustics, GPS, and Satellite Imagery |
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Why is accurate bathymetry data important?
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geologic history
biological habitat look @ physical processes |
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latitude
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represented in N or S from equator
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longitude
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great circles that cut the earth into equal halves
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are topographic maps completely flawless?
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no, they often have inconsistencies
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what is an ideal map projection
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one that preserves shape, distance, direction, and keeps continents intact
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rate of earth rotation
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15 degrees and hour
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plate tectonics
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processes affecting plate motions and the effects of those motions
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mantle
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surrounds the core
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astenosphere
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the upper the mantle that is outside of the mantle.
it's consistency is similar to that of glass that where it is close to its melting point |
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litosphere
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outer layer of the earth
similar to a skin of a pple |
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what are the two types of crust
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oceanic and continental
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what is theory of plate tectonics
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the surface of the earth is divided into a set of rigid plates that move, creating features of the Earth's surface
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how do plates move?
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the upper layer of the mantle is capable of flow that will grab against mountain bumps
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why to lithospheric plates float
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the plates are less dense than the aestenosphere
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why does oceanic crust sit lower than continental crust?
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it is denser
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What is the principle that supports the buoyancy of lithospheric plates
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arichemedes principle
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Mountains stand high because?
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the are compensated by a low desnity root
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what happens when mountains erode
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a higher density mantle will replace the mass and basins will subside in response to the added mantle mass
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what is the typical rate of flow for plates?
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1-20 cm/year
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what are terrestrial plates made of
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granite
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what are oceanic plates made of
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basalt
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what are the three types of plate boundaries
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divergent, convergent, transform
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list the five topographic features that follow a continent to the sea floor
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continental shelf
shelf break continental slope trench/continental rise abyssal plain |
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hydrosphere
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all the water in the lithosphere that are not combined in rocks and minerals
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what provides the energy that moves the lithospheric plates
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heat is transferred by convection throughout the athenosphere which causes upwelling and downwelling
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subduction zone
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where two plates collide and the more dense fall beneath the other
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what occurs at a divergent plate boundary
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plates are moving apart
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where do divergent boundaries occur
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at and ocean or continental boundary
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what are terrestrial examples of divergent boundaries
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great rift valley in Africa
Iceland |
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how many million years ago did pangea exist
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225 mya
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which is more dense, young or old plates?
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old plates
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what are the 3 types of convergent boundaries
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ocean-continent
ocean-ocean continent continent |
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what occurs @ convergent boundaries
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plates coming together
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What happens @ ocean-continent convergent collisions
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-the denser plate plunges beneath the continental plate
-the sediment and water being pulled down mixes and because it has a lower mp it becomes hot and bubbles up to form volcanoes |
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exotic terranes
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raised ocean floor that are old parts of an acretionary wedge
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active margin
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have steep narrow shelves
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passive marines
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broad shallow shelves
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what occurs @ ocean-ocean plate collisions
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older subducts below the younger. it forms a deep trench and creates an earthquake
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what occurs at continent-continent collision
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results in shallow earthquakes over a broad area
because the continental plates are too buoyant they dont descend into the mantle and instead they build up on one another to form a mountain chain |
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transform boundary
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when plates slide past on another
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fracture zone
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where plates move in the same direction
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Guyots
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seamounts with tops that are eroded away
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What were some old ideas related to plate tectonics
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plates were fixed
mountain uplifted the sea bed the earth was only a few 1000 years old |
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contraction theory
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old ideas that mountains were built from the cooling of tectonic plates
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What are the 4 things that give evidence to plate tectonics
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1. shape of continents
2. earthquakes along ridges 3. mid ocean ridges possessing young rocks 4. magnetic striping with magnetic reversals |
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What did Wegner contribute to plate tectonics?
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He noticed that the continents fit together. He named it pangea and coined the "continental drift theory"
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Who developed the mechanism for continental drift theory?
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Henry Hess with seafloor spreading.
begin @ ridges and end @ trenches |
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magnetic anomaly
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a demonstrated change in the Earth's magnetic field
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What was a problem with Wegener's theory?
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It couldn't explain how pangea came apart and it didn't take continental shelfs into account
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How can you distinguish continental similarities?
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mt chains that formed @ subduction zones
similar rocks and fossils glaciers |
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How do scientists know that the earth's magnetic field has changed directions?
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when magma coming up into ocean ridges cools, it contains iron oxides which will be cooled in the direction of the earth's magnetic field at the time.
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dip angle
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the angle at which the magnetic field is positioned in a ocean rock.
You are able to determine the latitude the rock was formed at based upon its latitude |
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what was the evidence that new rock emerges at ocean ridges
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as rock samples moved away from the ridge, they were older and thicker
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Why aren't continents older than the seafloor
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because they aren't being subducted
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Wilson Cycle
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explains the life and death of ocean basins.
6 steps: embryonic juvenile mature declining terminal saturing *Finished the idea that the plates are in motion |
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Hot spots, are they stationary?
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Some research has shown that volcanic islands may not be formed by stationary hot spots. It could originate just from a crack in the mantle
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why are guyots flat topped?
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because they break the ocean surface and are eroded by ocean waves
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why are hydrothermal vents called black smokers?
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because they are loaded with lots of metals
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How are ocean sediments classified?
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by their grain size or origin
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Sediment classification and size--what is significant about using it as a marker?
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Different size sediments will fall at different velocities depending on size, so sediments will often be sorted based upon size
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Terrigenous
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sediment that comes from land erosion
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Biogenic
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sediment that results as the remains of organisms
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hydrogenous
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sediment that results from minerals being precipitated out of the saturated ocean water located at deep hydrothermal vents
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cosmogenic
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sediments that result from meteorites hitting the atmosphere
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What are the 5 transport mechanisms for terrigenous sediment
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freshwater runoff, glaciers, waves, winds, and landslides
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Does new crust have sediment?
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Nope
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Red Clay
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fine grained clay that results from windbourne dust
it is found in areas of low biological activity, far from land, ocean ridges, and islands |
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What does white residue in a sediment signify?
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that has a high amount of calcium carbonate, therefore it must have come from a region of high biologic productivity
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what does preserved silica in a sediment signify?
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that core was from an area of high biologic productivity
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what does a dark brown top layer of a core signifiy?
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terrigenous material--close to shore
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Ice rafting and sediments
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within sediments there can be evidence of large grained particles that where held within icebergs and glaciers.
The could be car away from their original source |
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Manganese nodules
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form on dead items and in areas of low sedimentation
they grow at rates of 1-2 mm per million of years |
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Silica is equivalent to what word
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opal
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Foraminifera animal or plant?
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animal
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Foraminifera caco3 or silica?
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calcium carbonate
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coccolithophorids animal or plant?
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plant
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coccolithophords caco3 or silica?
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caclium carbonate
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diatoms zoo or phytoplankton?
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zoo
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diatoms silica or caco3?
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silica
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radiolaria zoo or phytoplankton?
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phyto
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radiolaria caco3 or sillica
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silica
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what determines where we find siliceous vs calcareous ooze?
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where they live
preservation |
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equation for sediment accumulation
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sed acc = rain flux - dissolution
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What is a typical rain flux rate for a productive area vs a non productive area?
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1 cm/ 1000 yrs vs 0.1 cm/1000 yrs
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Is CaCO3 more likely to dissolve at the surface or at the bottom of the ocean? How about Silica?
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CaCo3 is more likely to dissolve in deep ocean waters than at the surface. Opal is less understood but it typically dissolves more quickly at the surface because ocean waters are undersaturated in Si
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The solubility of caco3 increases with
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decrease temperature and increasing pressure
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see the dissolution of caco3 graph in the lecture notes
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done
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Why does the dissoltuion of calcium carbonate increase with depth?
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because below the carbonate compensation depth (CCD) the water is undersaturated with respect to caco3.
Why is it undersaturated? because the solubility product increases at depth and decreasing temperature, but also because the presence of carbon dioxide increases with depth (carbonic acid equilibrium) which takes more co3-2 out of the ocean solution. |
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would calcium carbonate be found in a deep ocean sediment core?
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no
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Can hotspots be fixed?
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yes
Hot spots are fixed places within the mantle or oceanic lithosphere, where rocks melt to generate magma. When a hot spot is situated in the oceanic lithosphere a class of volcanoes known as shield volcanoes is built. These are constructed on the deep ocean floor and may be build high enough to rise above sea level as volcanic islands. |
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Distinguish polar, ferrel, and hadley cells
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They occur at different areas along the equator
Polar--top Ferrel--around 30 N or S Hadley--subtropical cell near the equator |
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between what types of cells does downwelling occur?
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hadley and ferrel
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solstice
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When the sun is directly overhead at the tropic of cancer
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doldrums
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low pressure equatorial trough
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At areas of upwelling does more evaporation or precipitation occur?
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precipitation
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At areas of downwelling does more evaporation of precipitation occur?
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evaporation
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Explain monsoon winds
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Because of the different heat capacities of land and water, an atmospheric temperature gradient is created.
During the summer, the winds cycle from the sea to the land, causing rain upon the land, but during the winter, it causes a land to sea circulation which causes rain offshore |
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Explain El Nino
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Warmer waters replace the cool waters up at the surface (usually driven by upwelling) making the waters less nutrient rich and pushing down the thermocline. This results in the phytoplankton dying off and affecting the fishing industry
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Decipher between a sea breeze and a land breeze
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Because of the different heat capacities of land and ocean, they will give off and store heat in different ways. During the day, the ocean absorbs heat (without significant chanes to its temp), cooling the air, while the air is warmed on the surface of the land. The cool air moving from the ocean to the land is a "sea breeze." During the night, the opposite happens, the cool air is warmed by the ocean, and is cooled by the land, causing a "land breeze"
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What two types of intermolecule bonds does water have?
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Hydrogen bonds and van der waals
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At what temperature is water's maximum density occur? Why does this matter?
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Maximum density occurs at 4 degrees Celsius. This is important because it allows for ice to float on top of liquid water.
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Water and solvency? why does it matter?
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Water can dissolve more ions than any other liquid. This is important for transport of nutrients, especially for us.
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Water and its heat capacity. Why does it matter?
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Water has a high heat capacity, meaning that it takes a lot of energy in order to move its temperature. This is important because it allows the ocean to store a lot of energy, without having a drastic change in temperature
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Water and its latent heat of vaporization. Why is it special?
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Water has a high latent heat of vaporization, meaning that it will take a lot of energy to move it from a liquid to a gas. Once again, it allows for energy storage in the water.
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definition of temperature
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the average kinetic energy of molecules in a given substance
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definition of heat
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the total energy of a substance. All potential and kinectic
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sensible heat
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when the average kinetic energy increases leading to a temperature increase
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latent heat
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the energy that is used to break the molecules and lead to a phase change
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What molecule interaction is responsible for sea water's high bp and low fp
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H bonds
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When water is moving from a temperature of 0 to 4 degrees C, does its density increase or decrease?
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Density will increase
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What is the major energy source that power's the earth's weather systems
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latent heat through condenstation (e released and evaporation (E required)
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where do most of the ocean's salts come from
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river deposition of geological weathering
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is seawater concentrated river water?
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No because there is different distribution of elements
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Why is calcium and silica more abundant in the rivers than in the ocean
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because phytoplankton utilize these elements to create their shells
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Why is oceanic chlorine so high?
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because it is not reactive or biologically used
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explain residence time
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the average time an atom of an element spends in the ocean
the rate that elements are added must be equal to the rate that atoms are removed |
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equation to calculate residence time with regards to runoff rate and ocean area
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t equals the rate divided by the are of the ocean
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If an element has longer residence time in the ocean than in water, what does that imply
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that it will be in higher concentration in the ocean
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conservative elements and the law of constant proportions
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an element that has the same ratio to salinity throughout different oceans
note: usually has long residence time |
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how does adding salt to water change its density, fp and bp
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lower fp, high bp and large dens
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what causes water to be less dense than its liquid state?
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H bonding
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what makes salinity different globally?
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evaporation, ice melt, and river run off
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be able to understand a salinity and temperature profile
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done
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A low T does change in t or s have more effect on density
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s
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phynolcine
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zone of rapid change in density
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thermocline
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zone of rapid change in termperature that leads to changes in densityh
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halocline
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zone of rapid change in salinity that leads to changes in density
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isopycnal
isothermal isohaline |
constant density
temp sal |
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does salt water have a maximum density?
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not really, in generall it continues to get denser as it cools until ice is formed
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troposphere
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the area between the earth's surface and the first 16 to 18 km into the atmosphere
it is where the most changes in density occur |
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black body
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object that absorbs all light that falls on it
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what must occur in order to keep the earth at a constant temperature?
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the absorbed solar radiation must equal that which is lost in longwave radiation
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Explain the "bare rock" model
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Based in the idea that incoming solar radiation must balancing outgoing.
Incoming radiation depends upon the area, the sun's ouput, and albedo outgoing radiation depends upon the earth acting as a black body at a constant temperature |
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What is the temperature that results from the bare rock model? What is the actual temperature of the earth's surface?
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-18 degrees Celsius but the earth's surface is 15 degrees Celsius
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Why is the earth's surface considerably warmer? What is the mechanism?
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The greenhouse effect. Gases in the atmosphere absorb outgoing longwave radiation and reemit it back towards the earth
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why does incoming solar radiation onto the earth's surface decrease with latitude?
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the poles are farther away from the sun than the equator, leading to the rays having to travel farther to reach the poles, decreasing its intensity.
Also at the poles, area increases with latitude, but there is still the same amount of radiation coming from the sun. Therefore, the amount of energy per area decreases as well. |
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ozone depletion
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is caused primarily by CFCs that have a long enough residence time to reach the upper portions of the troposphere. they react with ozone and deplete the amount available. This allows more UV to enter the earth that originally would have been backscattered by the ozone.
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explain the earth's heat budget and how heat is distributed throughout the Earth
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The latitudinal imbalance of heat drivies a climate cycle in order to distribute the heat and create an equilibrium.
Oceans and atmosphere work to redistribute this heat. Water from the tropical oceans is evaporated, removing significant quantities of energy from the ocean (without decreasing its temperature due to heat capacity of sea water). Warm air can hold more moisture than cooler air, and warm moist air is less dense than cool dry air (because water is less dense than atm. nitrogen). As a result, the warm air mass will rise to higher altitudes. Upon reaching a higher altitude, the air cools and is unable to hold as much moisture, which leads to condensation, releasing the heat gained from prior evaporation. Heat is also transported throughout the ocean via currents. |
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explain the latitudinal heat imbalacne
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The poles have less heat than the equator because they receive less incoming radiation, but release longwave radiation at the same rate as the equator. Leading to a deficit at the poles and surplus at the equator
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climate vs weather
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day to day variations vs long term avg patterns
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explain what would occur in atm circulation in a non rotating earth
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the air masses would move from the poles (high pressure) to the equator (low pressure)
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Explain the coreolis force
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Air and water masses are free moving objects with respect to the Earth. An observer on the earth that is rotating with the earth, will see an object with a straight path move in a curved fashion. This occurs due to centripetal force and tangential motion of a free moving object.
In the N. Hemisphere we observe a deflection by the coreolisis force to the right and in the S. hemisphere we observe a deflection to the L |
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How does the coreolisis force affect air masses
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air masses that are moving north or south are deflected by the coreolisis force.
In the North, this makes the air mass traveling fromt the equator have an eastward velocity In the South, this makes the air mass traveling from the equator have a westward velocity |
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Where is the coreolisis force the greatest?
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at the poles
it is considered to be zero at the equator |
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explain the formation of trade winds
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are formed from warm air rising, cooling at altitude, then sinking to the ocean to be warmed again. The sinking of cool dry air is deflected bye the coreolis force, as is the warm air moving towards the equator. This deflection results in both the NE trades and the SE trades having a net warm air movement pushing westward at the equator, and eastward away from the equator
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explain the formation of the westerlies
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warm air rises from mid latitudes towards the poles, deposits precipitation and heat, and cool air moves back towards the mid latitudes. The stronger movement of air from the warm air rises comes from the southwest, hence the name
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jet stream
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swiftly moving W to E currents in the high troposphere
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doldrums
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occur in a low pressure belt @ the equator
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explain sea breezes
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occurs during the day because of the high heat capacity of water, heated air by the land is cooled by the surface of the ocean. At night, a land breeze occurs where the ocean heats the air that is cooled by the land.
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Explain El Nino
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Peru is an area which typically has a lot of upwelling. During El Nino, warm water comes and stratifies the water column and suppresses upwelling, driving down the thermocline. This results in less productivity because the waters are less nutrient rich
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Explain the difference in ocean salinity in relation to atmospheric cells
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in areas of atmospheric upwelling, there is more preciptiation, which leads to a decrease in surface salinity. Some areas have higher salinity because more evaporation occurs than precipiation
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what is a water mass? what is usually used to define it?
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A water mass is a volume of sea water that has similar physical properties that are retained
T and Salinity are often used as markers CFCs do too sometimes |
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what is thermohaline circulation driven by?
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different densities
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what defines the mediterranean as a water mass
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high evaporation and little precipitation leads to very salty water that is warm
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what happens when two water masses mix
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they become an intermediate temperature and salinity compared to the ratio they are mixed
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compare the North Atlantic Deep Water, Antarctic Intermediate Water, and Antartctic Bottom Water
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NADW is more salty than the other two
AAIW is the least dense because it is less salty @ a slightly higher T AABW is the coldest, but is the most dense |
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How is deep water formed?
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In the antartic, cold, salty water is formed through ice exclusion. Cold air moves across the surface of the ocean, cooling the temperatures and leading to ice formation which excluses salt and leaving behind brine.
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how is NADW formed?
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warm salty water is transported by the gulf stream into the deep waters near greenland where the water will cools and sink during the winter.
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Why is the AAIW less saltly?
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due to precipitation
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Why is there no deep water formation in the N pacific
|
because the barrier between alaska and russia provides shallow enough water that the cool water from the poles is inaccessible and it is not saltly
|
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Explain the Meridonal overturning circulation
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it is the global ocean conveyor belt that is driven by different water mass densities. new water begins in the NA and ends in the pacific
takes 1000 years to copmlete |
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Explain ekman motion and ekman spirals
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Ekman results as a balance between wind stress and the coreolsis force
as KE from wind stress is transferred down the water column, each "layer" will move at a different speed and be subject to offset from the coreolisis force. Each one moves at a 45 degree angle relative to the surface current above it. However, the net transport is that of 90 degrees, or perpendicular to the motion of the wind |
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explain what a geostrophic current is
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it is a balance between the coreolisis force and pressure gradients
A pressure gradient results from uneven sea surface heights. A high SSH has more pressure than a low SSH, which leads to a pressure imbalance that drives from low to high. In geostrophic currents, a pressure gradient is built up opposite to the force of the coreolisis force. This causes a balance of accelerations and a steady state velocity movement of the ocean current. |
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Explain ocean gyres
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They form in response to interactions between wind and ekman transport between the trade winds and westerlies. The net effect is that water is continually pushed toward the center of the ocean. A pressure gradient is then forced (High p at the center), but this is counteracted by the coreolis force. This leads to a resultant geostrophic currentq
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What are the forces that affect the acceleration of the ocean?
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pressure gradients
coriolis friction (wind stress and internal) internal decreases acceleration while wind stress increases it |
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explain inertial oscillations
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the absence of friction and pressure gradients cause a fluid to acceleration to balanced by the coriolis force. It causes it to spin and spin in circles
|
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what is the only current that runs unbroken?
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the antartic counter boundary current
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What is the fastest current
|
western boundary because it is narrow, warm, and movees from the eq to the poles
it is not productive |
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what is the slowest current
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the easter boundary which moves from N to S and leads to productivity
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