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Definition of Oceanography
Known as marine science, it is the process of discovering unifying principles in data obtained from the ocea, its associated life forms, and its bordering lands.
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Branches of Oceanography: Geological
Composition of innter earth the mobility of the crust the characteristics of seafloor sediments and the history of the Earth's Ocean
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Branches of Oceanography: Physical Oceanographers
study and observe wave dynamics, currents and ocean-atmospheric interactions.
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Branches of Oceanography: Chemical Oceanographers
Study the oceans dissolved solids and gases and their relationship to the geology and biology of the ocean as a whole
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Branches of Oceanography: Biological
Work with nature and distribution of marine organisms, the impact of oceanic and atmospheric pollutants on organisms, the isolation of disease fighting drugs from marine species and the yields of fisheries.
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Origin of the Ocean
Two theories: out gassing and water vapors came out of the earth to then rain down on it eventually creating an ocean or comets impacted earth from outer space that were carrying ice.
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Origin of Life in the Ocean
organic materials came from comets which then mingled with the inorganic compounds. Forming building blocks for life the first living organisms were produced through biosynthesis.
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Work of Matthew Maury
- -started depot of charts and insturments
- -read through old logs and documented weather locations
- -wrote a book called the physical geography of the sea
- -the "bible" of physical oceanography
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Challanger expedition
- operated by the british navy
- steam engine
- 3 and 1/2 years and 80,000 miles of data collection of the depths of the ocean, currents, weather, sediment samples, and biological samples, 4717 species discovered
- 6 scientists named the science Oceanography
- 1872
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Developement of Echo Sounding
- 1920
- Sound bounces over the sea floor, returns echo
- Can tell the depth while the ship is moving
- Still used today
- 1925-1926 german vessel
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Glomar Challenger
- 1960
- deep sea drilling project
- Mineral deposits on the sea floor
- didnt make much money but it let to how the sea floor was formed, provided theories of seafloor spreading and plate techtonics
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Satellite oceanography
- Oceanography from satallites
- reads temp. with infared scanner
- didnt have it until 1970s
- 1978 seasat was the first satallite to have only the purpose of viewing the ocean
- measured chlorophyl from ocean color however satalites can only see the sea surface
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True North vs Magnetic North
- true north is the axis of the earth's rotation
- magnetic north is the north the compass points to which is in greenland.
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Magnetic Declination
- 2' per year
- the rate at which the magnetic north moves towards the west.
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Compass Bearing
the direction from one point to another, expressed as an angle relative to true north.
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Ship's Course
- expressed in defrees, is the intended direction of travel relative to true north.
- ex: 180 degrees means towards south
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Ships heading
the direction toward which the ship is actually moving regardless of its intending course
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Nautical miles vs Statute Miles
Nautical miles is one minute of latitude or 1.15 statute miles while statute miles are the miles we use everyday
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Time zones are seperated hourly by how many degrees?
15 degrees
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GMT?
Greenwhich Mean Time
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UTC
Coordinated Universal Time
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4 Layers of the Earth
- crust
- mantle
- outer core
- inner core
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New Layers of the crust
- Lithosphere on top
- asthenosphere on bot
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Evidence of earth inner layers
seismic waves from earthquakes indicated the interior of the earth wasnt solid since it passed through it much quicker
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Plates
Earths outer layer which consists of about a dozen seperate major lithosperic plates
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Evolution of theories of continental drift and seafloor spreading
- Wegener continental drift the continents were once together
- Mid ocean were spreading centers and the source of new ocean floor rising from the asthenosphere
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Plate Techtonics
- John Tuzo Wilson
- seafloor spreading + continental drift
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Plate Boundaries
- Convergent (subduction): Where plate push against one another, usually one subducts underneath another
- Divergent: spreading centers ocean ridges
- Transform: shearing crust is neither built or destroyed
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geologic evidence confirming plate movement
- fossil record
- radiometric dating
- paleomagnetic stiping
- hot spots
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difference between active and passive continental margins
- divergent= passive
- converging/submerging=active
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continental shelf
shallow submerged extensions of a continent
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shelf break
the abrupt transition from continental shelf to continental slope
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continental slope
the transition between the gently descending continental shelf and the deep ocean floor
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continental rise
when the oceanic crust at the base of the continental slope is covered by an apron of accumulated sediment
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turbidity currents
underwater avalanches of sediments
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5 deep ocean basin features
- mid ocean ridges
- abyssal plains
- abyssal hills: small sediment covered extinct volcanoes
- seamounts, guyots
- trenches
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how are sediments measured and sampled?
clamshell samplers, core sampler, they then take it out and refrigerate it.
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seismic profiling
- type of ecosounding
- can see different layers within the sediment
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sediment classification
- terrigenous
- biogenous
- hyrdrogenous
- cosmogenous
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size of sediments
- boulder
- cobble
- pebble
- granule
- sand
- silt
- clay
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siliceous vs calcareous oozes
- siliceous are made from silica rish residues; diatoms
- calcareous are made from calcium containing minerals; cocolithophores
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calcium carbonate compensation dpth
the rate at which the amount of calcareous sediments are being supplied to the seabed equals the rate it is dissolved
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hydrogenous sediments
precipitation of dissolved minerals from water, often by bacteria
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cosmogenous
dust from space, meteorite debris
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Rill marks
results of the tide draining out. looks like stream beds
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swash marks
lines of debris that mark the last of the high tide
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ripples
caysed vt currents flowing over a sandy bottom when the tides are in. currents are more angular while waves are like hills
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backwash marks
waves coming in at an angle and back another; look like diamonds
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beach cusps
waves coming at an angle
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Human Interference with Beaches 3 types
- making :
- groins
- seawall
- importing sand
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erosional coasts
new coasts in which the dominant processes are those that remove coastal material
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depositional coasts
steady or growing because of their sediment accumulation rate or the action of living organisms
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