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185 Cards in this Set

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  • Back
how much of the earth is covered by ocean water?
70 percent
summarize the big bang
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
when did the earth form and from what?
about 4.6 billion years ago from a supernova of a star
when the did earth's ocean's form? and from what?
about 4.2 bya from outgassing of the earth's interior
how is the earth's core is structured?
The heaviest elements are towards the center and the ligheter elements are towards the outer edge
what creates the heat at the earth's core
radioactive decay
topographic
depicts height and land surface
bathymetric
depicts the depth of the ocean below sea level
seamount
underwater volcanoes
what was the oxygen revolution and who lead it?
when there was enough oxygen in the air that wasn't being used to oxidize the rocks. Cyanobacteria produced the oxygen
what is a problem with the mercator projection?
it distorts distance, shape.

the shortest distance is not between two points is not a line
what is good about the mercator projection
it preserves direction
what is occurring at the mid atlantic ridge?
breaking apart and forming of new plates
where does the most biological productivity occur?
at the contintental shelf
hypsographic curve
demonstrates the high and low points of the land/ocean
What are the old/new ways that the ocean depth is measured
Old- rock and string (lead line)

New-Acoustics, GPS, and Satellite Imagery
Why is accurate bathymetry data important?
geologic history
biological habitat
look @ physical processes
latitude
represented in N or S from equator
longitude
great circles that cut the earth into equal halves
are topographic maps completely flawless?
no, they often have inconsistencies
what is an ideal map projection
one that preserves shape, distance, direction, and keeps continents intact
rate of earth rotation
15 degrees and hour
plate tectonics
processes affecting plate motions and the effects of those motions
mantle
surrounds the core
astenosphere
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
litosphere
outer layer of the earth

similar to a skin of a pple
what are the two types of crust
oceanic and continental
what is theory of plate tectonics
the surface of the earth is divided into a set of rigid plates that move, creating features of the Earth's surface
how do plates move?
the upper layer of the mantle is capable of flow that will grab against mountain bumps
why to lithospheric plates float
the plates are less dense than the aestenosphere
why does oceanic crust sit lower than continental crust?
it is denser
What is the principle that supports the buoyancy of lithospheric plates
arichemedes principle
Mountains stand high because?
the are compensated by a low desnity root
what happens when mountains erode
a higher density mantle will replace the mass and basins will subside in response to the added mantle mass
what is the typical rate of flow for plates?
1-20 cm/year
what are terrestrial plates made of
granite
what are oceanic plates made of
basalt
what are the three types of plate boundaries
divergent, convergent, transform
list the five topographic features that follow a continent to the sea floor
continental shelf
shelf break
continental slope
trench/continental rise
abyssal plain
hydrosphere
all the water in the lithosphere that are not combined in rocks and minerals
what provides the energy that moves the lithospheric plates
heat is transferred by convection throughout the athenosphere which causes upwelling and downwelling
subduction zone
where two plates collide and the more dense fall beneath the other
what occurs at a divergent plate boundary
plates are moving apart
where do divergent boundaries occur
at and ocean or continental boundary
what are terrestrial examples of divergent boundaries
great rift valley in Africa
Iceland
how many million years ago did pangea exist
225 mya
which is more dense, young or old plates?
old plates
what are the 3 types of convergent boundaries
ocean-continent
ocean-ocean
continent continent
what occurs @ convergent boundaries
plates coming together
What happens @ ocean-continent convergent collisions
-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
exotic terranes
raised ocean floor that are old parts of an acretionary wedge
active margin
have steep narrow shelves
passive marines
broad shallow shelves
what occurs @ ocean-ocean plate collisions
older subducts below the younger. it forms a deep trench and creates an earthquake
what occurs at continent-continent collision
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
transform boundary
when plates slide past on another
fracture zone
where plates move in the same direction
Guyots
seamounts with tops that are eroded away
What were some old ideas related to plate tectonics
plates were fixed
mountain uplifted the sea bed
the earth was only a few 1000 years old
contraction theory
old ideas that mountains were built from the cooling of tectonic plates
What are the 4 things that give evidence to plate tectonics
1. shape of continents
2. earthquakes along ridges
3. mid ocean ridges possessing young rocks
4. magnetic striping with magnetic reversals
What did Wegner contribute to plate tectonics?
He noticed that the continents fit together. He named it pangea and coined the "continental drift theory"
Who developed the mechanism for continental drift theory?
Henry Hess with seafloor spreading.

begin @ ridges and end @ trenches
magnetic anomaly
a demonstrated change in the Earth's magnetic field
What was a problem with Wegener's theory?
It couldn't explain how pangea came apart and it didn't take continental shelfs into account
How can you distinguish continental similarities?
mt chains that formed @ subduction zones
similar rocks and fossils
glaciers
How do scientists know that the earth's magnetic field has changed directions?
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.
dip angle
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
what was the evidence that new rock emerges at ocean ridges
as rock samples moved away from the ridge, they were older and thicker
Why aren't continents older than the seafloor
because they aren't being subducted
Wilson Cycle
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
Hot spots, are they stationary?
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
why are guyots flat topped?
because they break the ocean surface and are eroded by ocean waves
why are hydrothermal vents called black smokers?
because they are loaded with lots of metals
How are ocean sediments classified?
by their grain size or origin
Sediment classification and size--what is significant about using it as a marker?
Different size sediments will fall at different velocities depending on size, so sediments will often be sorted based upon size
Terrigenous
sediment that comes from land erosion
Biogenic
sediment that results as the remains of organisms
hydrogenous
sediment that results from minerals being precipitated out of the saturated ocean water located at deep hydrothermal vents
cosmogenic
sediments that result from meteorites hitting the atmosphere
What are the 5 transport mechanisms for terrigenous sediment
freshwater runoff, glaciers, waves, winds, and landslides
Does new crust have sediment?
Nope
Red Clay
fine grained clay that results from windbourne dust

it is found in areas of low biological activity, far from land, ocean ridges, and islands
What does white residue in a sediment signify?
that has a high amount of calcium carbonate, therefore it must have come from a region of high biologic productivity
what does preserved silica in a sediment signify?
that core was from an area of high biologic productivity
what does a dark brown top layer of a core signifiy?
terrigenous material--close to shore
Ice rafting and sediments
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
Manganese nodules
form on dead items and in areas of low sedimentation

they grow at rates of 1-2 mm per million of years
Silica is equivalent to what word
opal
Foraminifera animal or plant?
animal
Foraminifera caco3 or silica?
calcium carbonate
coccolithophorids animal or plant?
plant
coccolithophords caco3 or silica?
caclium carbonate
diatoms zoo or phytoplankton?
zoo
diatoms silica or caco3?
silica
radiolaria zoo or phytoplankton?
phyto
radiolaria caco3 or sillica
silica
what determines where we find siliceous vs calcareous ooze?
where they live
preservation
equation for sediment accumulation
sed acc = rain flux - dissolution
What is a typical rain flux rate for a productive area vs a non productive area?
1 cm/ 1000 yrs vs 0.1 cm/1000 yrs
Is CaCO3 more likely to dissolve at the surface or at the bottom of the ocean? How about Silica?
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
The solubility of caco3 increases with
decrease temperature and increasing pressure
see the dissolution of caco3 graph in the lecture notes
done
Why does the dissoltuion of calcium carbonate increase with depth?
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.
would calcium carbonate be found in a deep ocean sediment core?
no
Can hotspots be fixed?
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.
Distinguish polar, ferrel, and hadley cells
They occur at different areas along the equator

Polar--top
Ferrel--around 30 N or S
Hadley--subtropical cell near the equator
between what types of cells does downwelling occur?
hadley and ferrel
solstice
When the sun is directly overhead at the tropic of cancer
doldrums
low pressure equatorial trough
At areas of upwelling does more evaporation or precipitation occur?
precipitation
At areas of downwelling does more evaporation of precipitation occur?
evaporation
Explain monsoon winds
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
Explain El Nino
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
Decipher between a sea breeze and a land breeze
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"
What two types of intermolecule bonds does water have?
Hydrogen bonds and van der waals
At what temperature is water's maximum density occur? Why does this matter?
Maximum density occurs at 4 degrees Celsius. This is important because it allows for ice to float on top of liquid water.
Water and solvency? why does it matter?
Water can dissolve more ions than any other liquid. This is important for transport of nutrients, especially for us.
Water and its heat capacity. Why does it matter?
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
Water and its latent heat of vaporization. Why is it special?
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.
definition of temperature
the average kinetic energy of molecules in a given substance
definition of heat
the total energy of a substance. All potential and kinectic
sensible heat
when the average kinetic energy increases leading to a temperature increase
latent heat
the energy that is used to break the molecules and lead to a phase change
What molecule interaction is responsible for sea water's high bp and low fp
H bonds
When water is moving from a temperature of 0 to 4 degrees C, does its density increase or decrease?
Density will increase
What is the major energy source that power's the earth's weather systems
latent heat through condenstation (e released and evaporation (E required)
where do most of the ocean's salts come from
river deposition of geological weathering
is seawater concentrated river water?
No because there is different distribution of elements
Why is calcium and silica more abundant in the rivers than in the ocean
because phytoplankton utilize these elements to create their shells
Why is oceanic chlorine so high?
because it is not reactive or biologically used
explain residence time
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
equation to calculate residence time with regards to runoff rate and ocean area
t equals the rate divided by the are of the ocean
If an element has longer residence time in the ocean than in water, what does that imply
that it will be in higher concentration in the ocean
conservative elements and the law of constant proportions
an element that has the same ratio to salinity throughout different oceans

note: usually has long residence time
how does adding salt to water change its density, fp and bp
lower fp, high bp and large dens
what causes water to be less dense than its liquid state?
H bonding
what makes salinity different globally?
evaporation, ice melt, and river run off
be able to understand a salinity and temperature profile
done
A low T does change in t or s have more effect on density
s
phynolcine
zone of rapid change in density
thermocline
zone of rapid change in termperature that leads to changes in densityh
halocline
zone of rapid change in salinity that leads to changes in density
isopycnal
isothermal
isohaline
constant density
temp
sal
does salt water have a maximum density?
not really, in generall it continues to get denser as it cools until ice is formed
troposphere
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
black body
object that absorbs all light that falls on it
what must occur in order to keep the earth at a constant temperature?
the absorbed solar radiation must equal that which is lost in longwave radiation
Explain the "bare rock" model
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
What is the temperature that results from the bare rock model? What is the actual temperature of the earth's surface?
-18 degrees Celsius but the earth's surface is 15 degrees Celsius
Why is the earth's surface considerably warmer? What is the mechanism?
The greenhouse effect. Gases in the atmosphere absorb outgoing longwave radiation and reemit it back towards the earth
why does incoming solar radiation onto the earth's surface decrease with latitude?
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.
ozone depletion
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.
explain the earth's heat budget and how heat is distributed throughout the Earth
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.
explain the latitudinal heat imbalacne
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
climate vs weather
day to day variations vs long term avg patterns
explain what would occur in atm circulation in a non rotating earth
the air masses would move from the poles (high pressure) to the equator (low pressure)
Explain the coreolis force
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
How does the coreolisis force affect air masses
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
Where is the coreolisis force the greatest?
at the poles

it is considered to be zero at the equator
explain the formation of trade winds
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
explain the formation of the westerlies
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
jet stream
swiftly moving W to E currents in the high troposphere
doldrums
occur in a low pressure belt @ the equator
explain sea breezes
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.
Explain El Nino
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
Explain the difference in ocean salinity in relation to atmospheric cells
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
what is a water mass? what is usually used to define it?
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
what is thermohaline circulation driven by?
different densities
what defines the mediterranean as a water mass
high evaporation and little precipitation leads to very salty water that is warm
what happens when two water masses mix
they become an intermediate temperature and salinity compared to the ratio they are mixed
compare the North Atlantic Deep Water, Antarctic Intermediate Water, and Antartctic Bottom Water
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
How is deep water formed?
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.
how is NADW formed?
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.
Why is the AAIW less saltly?
due to precipitation
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
Explain the Meridonal overturning circulation
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
Explain ekman motion and ekman spirals
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
explain what a geostrophic current is
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.
Explain ocean gyres
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
What are the forces that affect the acceleration of the ocean?
pressure gradients
coriolis
friction (wind stress and internal)

internal decreases acceleration while wind stress increases it
explain inertial oscillations
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
what is the only current that runs unbroken?
the antartic counter boundary current
What is the fastest current
western boundary because it is narrow, warm, and movees from the eq to the poles

it is not productive
what is the slowest current
the easter boundary which moves from N to S and leads to productivity