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79 Cards in this Set

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What are the 7 uses of the ocean?
Food, Transport, Atmospheric Replenishment, Recreation, Dump, Petroleum (sea-floor-near shore), Defense Barrier
Who first calculated the Earth's circumference?
Eratosthenes
What was the first population to really explore the oceans, and who were they followed by?
Phoenicians, followed by Greeks and Romans
Who were the first Europeans to make it to the Americas, Iceland, and Greenland (sailing west from northern Europe)? What year was this? What allowed them to temporarily settle there?
The Vikings, 900 A.D., a temporary climate fluctuation.
Why did Europeans want to explore the oceans?
They wanted access to China and India for trade because land routes were too dangerous.
After Christopher Columbus, what did Magellan accomplish, how, and what's the time period?
He circumnavigated the world using celestial navigation, maps and a compass (1519-1522)
Which European in the 1700s took oceanography samples while exploring the oceans?
Captain Cook
What was the first ocean expedition undertaken specifically for scientific purposes (& oceanography), when did it occur and how long did it take?
Challenger Expedition - Britain - 1872-1876 (4 years)
How long did the results from the Challenger Expedition take to synthesize? How many new genera were catalogued? How many new species?
23 years - 700 new genera - 4400 new species
What did Ben Franklin observe?
the Gulf Stream
What are the four types of oceanography?
chemical, physical, geological, and biological
What are the lungs of the planet, and how much oxygen do they provide that humans breathe?
the oceans, they take CO2 from the air and replace it with oxygen. 70%
What are the four steps of scientific inquiry?
Observations, Hypothesis, Testing, and Theory
After the Vikings, which chinese dynasty explored the oceans and why?
The Ming dynasty to add to the glory of their empire.
What percent of the earth is covered with oceans?
70.8%
Where did the Fram voyage travel to and what did it determine, and what are "Nansen Bottles"
The Fram voyage was a Norwegian voyage to the Artic and Antartica and they determined that there is no artic continent, if there is an ocean. "Nansen Bottles" were used to sample seawater at depth and were developed on this voyage.
Who is considered the driving force that led to Oceanography being recognized as a science & developed the dredge?
Alexander Agassiz (late 1800s)
How did WWII lead to big techonological advances in oceanography?
much shipping was taking place, submarine warfare, SONAR TECHNOLOGY developed for U-Boats and is now used to map seafloor
What is the maximum ocean depth?
11,000 meters
What is used for large-scale bathymetry?
Satellite Gravity
What can sonar tell you other than the depth of the ocean?
It can tell you how soft or hard the seafloor is by determining the sharpness of the returning sounds. It can detect recent volcanic eruptions and you can see faults.
What are air guns and seismic surveys used for?
seeing beneath the seafloor
how many miles is one kilometer?
0.62 miles (62 mph = 100 km/h
What is a Nautical Mile?
The distance of one minute (1/60th of a degree) of latitude.
What measures water depth?
sonar and satellites
What methods are used to determine Sea Floor Bathymetry?
radar satellite, sonar (travel time), and photography
What Exclusive Economic Zone(EEZ) int'l law was adopted in 1982 and took binding effect in 1994?
The Law of the Sea
what is 1 knot equivalent to?
1 N.M./hr
What did the "Law of the Sea" set as the limited area over which a nation has complete jurisdiction? What is the limited area of an Exclusive Economic Zone alotted to each nation, and why didn't the law take effect immediately?
12 N.M. limit, 200 N.M. limit, overlap areas had to be negotiated
According to the Big Bang Theory, how old is the universe?
13.7 billion years old
In the first millionth of a second after the universe was born, what happened, and what 2 things followed within the first minute?
elementary particles formed (quarks), then electrons neutrons and protons, then hydrogen and helium formed
How long was the "Dark Ages," a time where there was just gas, no stars, after the big bang?
0.2 billion years
How did the stars begin to form?
gravitational collapse
How old is our Solar System?
4.567 billion years old
What process does our sun undergo that produces elements up to carbon?
Nuclear Fusion - atomic nuclei moving very fast (i.e. hot) collide and combine to form new nuclei + energy
What caused the creation of heavy elements before the birth of our solar system?
a supernova explosion - barely preceded our solar system's formation
What is differentiation?
dense materials like iron and nickel concentrate in the core of the earth, and the other materials were layered due to density
What were 3 sources of earth's heat?
1. decay of radioactive elements, 2. original condensation (collision energy), 3. core formation (collisions in middle)
What is the age of the oldest continental crust?
4.0 billion years old
What is the age of the oldest oceanic crust?
0.18 billions years old
What two theories are there about the creation of the atmosphere?
1. Volcanic outgassing
2. Late Veneer Hypothesis - gasses derived from late smaller impacts (but the concentration of hydrogen in comets is not the same as ours)
What are seven defining characteristics of life on earth?
1. separated from its environment
2. self-replicating
3. uses (stores) energy
4. Chemical Restraints: H20 bearing - solvent for biochemical reactions
5. carbon based (organic molecules)
6. adaptable to environment
7. able to change
What are the 6 bathymetric provinces, and the average water depths three of them?
Coastal Plain
Continental Shelf (0-300m-average 130m)
Continental Slope
Continental Rise
Abyssal Plain (5500m)
MidOcean Ridge (2600m)
What is NASA's definition of life?
Life is a self-sustaining chemical system capable of Darwinian evolution.
What are two possibilities for the origins of the building blocks of life-complex organic molecules?
1. meteorites - amino acids are present
2. terrestrial - hydrothermal vents (Miller Urey synthesis)
What provided the oxygen to oxidize the surface of the earth?
cyanobacteria - blue-green algae
1 degree of latitude equals how many nautical miles?
60
What is a hypsographic curve?
a bimodal distribution of elevations
What are two features of the mid-ocean ridge system and what are they?
1. Transform fault - allows plates to move past one another, producing shallow but strong seismic earthquakes in the lithosphere and is a plate boundary
2. Fracture zone - non-seismically active area, not a plate boundary
What is the range of depths of trenches?
6-11,000m
What are the fastest and slowest sea floor spreading rates?
fastest: 20 cm/yr (hair growth)
slowest: 1 cm/yr (fingernail growth)
Which of the Atlantic of Pacific Oceans is fast spreading and which is slow spreading?
Atlantic Ocean = slow-spreading
Pacific-Ocean = fast-spreading
What forms submarine canyons, and what province are they located on?
Turbidity flows (a mix of sediment and water that flows downslope due to gravity), the Continental Slope
what forms the continental rise?
sediment from turbidity flows
What are seamounts?
mostly old volcanoes that are inactive now
What are "black smokers"?
Hydrothermal vents that emit water that is black due to the presence of dark-colored metal sulfides.
What is the Plate Tectonic Theory?
there are rigid lithospheric plates at the earth's surface that move over a solid but plastic asthenosphere.
What are the average thicknesses of continental and oceanic crust?
continental crust: 35 km-70 km
oceanic crust: 6 km
What are the average densities of continental and oceanic crust?
continental - 2.7 g/cm2
oceanic - 3.0 g/cm2
What is the principle of isostacy?
greater height above the surface requires more low-density material beneath it. Ocean crust sits low and is thin. Continental crust rides higher and must be supported by additional buoyant material beneath it. Mountains ride highest and are supported by the thickest crust.
What are the three types of Plate Boundaries and what kind of earthquakes do they cause?
1. Mid-Oceanic Ridge - site of seafloor spreading - divergent plate boundary - small earthquakes
2. Subduction Zone With Trench - ocean crust is subducted into the mantle - convergent plate boundary - large earthquakes
3. Transform Fault - plates slide past each other, no creation or destruction (large earthquakes)
Where is the thickest continental crust and where is the thinnest?
thickest: himilayas (mt. everest)
thinnest: California, Sacramento Valley
What theory did Alfred Wegener propose in the 1920s and why did people reject it? What mechanism did he propose for this?
He proposed the theory of Continental Drift in 1912. There was a lot of misfit between continental shorelines, however. He proposed also that the continents rode on oceanic crust (bad mechanism).
What are some pieces of land evidence for the continental drift theory?
features like mountain ranges are continuous when continents are placed together, deposits of the ancient ice cap occupied one area, motion of the ice sheet from the ice age away from the center of Pangaea was apparents, and some old nonmarine animals were the same on different continents
what are some pieces of oceanic evidence for plate tectonics?
1. sea-floor spreading/marine magnetic anomolies - there were "stripes" of normal and reversed polarity ocean crust and their irregularity allowed scientists to see that they were symmetrical about the crest of the mid-ocean ridge
What are ophiolites?
slices of ocean crust thrust into continents
What is the "Benioff Zone"?
A seismic zone which representsa subducting plate in a convergent plate boundary
What is the seismic difference between oceanic lithosphere returning to asthenospheric mantle and cold lithosphere going into cold asthenosphere?
The first causes big earthquakes and the second smaller ones because the rocks are cold so they are brittle and break.
What is "Moho"?
It's a seismic discontinuity where you go from crust (formed by molten basalt magma) to mantle (melted to form basalt magma).
What are "Island Arcs"?
when oceanic lithosphere subducts beneath oceanic lithosphere (tonga, marianas, western aleutians)
What are "Continental Arcs"?
where oceanic lithosphere subducts beneath a continent (andes, mexican volanoes, cascade volcanoes, indonesia)
Are transform faults and trenches volcanically active?
no
How much volcanic output takes place at the midocean ridges? How much in island and continental arcs? what are the rest caused by?
midocean ridges - 85%
island and continental arcs - 10%
the rest are interplate volcanoes caused by mantle hotspots or mantle plumes
How was Hawaii formed?
by the movement of the Pacific plate over a hotspot
How do we know how the planes are moving?
we reference fixed hotspots
What does the lithosphere encompass, and what about the asthenosphere?
the lithosphere is the crust + the upper mantle and the asthenosphere is the rest of the upper mantle.
What is the age of the oldest peridotite beneath the moho?
1.2 billion years old
What explains the apparent polar wander?
the continental drift theory
Which is felsic and which is mafic--the continental crust or the oceanic crust?
continental crust - felsic (lower percentage of heavier elements)
oceanic crust - mafic (higher percentage of heavier elements such as Mg and Fe)