Oceanography 200
• Ascending and descending air gets twisted by
Coriolis Effect → drives circulation
o Drawn into and merges with a monsoonal circulation =
monsoon trough (SE Asia) •
o Near the equator =
near-equatorial trough
• Origin of Daily Coastal airflow
o Afternoon • Cool air descends • Cooler sea • Onshore flow • Warmer land
• Dense at surface
o Cold air is denser
• Coriolis Effect
o Speed at equator ~1700km/h (fattest part of the Earth) o Speed in Kingston ~1200km/h - we don't have to go as far to make a 360º rotation o Follows curved lines of longitude • Northern hemisphere - things will be deflected to the right • Southern hemisphere - deflected to the left
vikings
overlapping hull so was flexible and could go into rough seas
• Incoming radiation -
light - short-wave radiation
outer core
liquid
how do we access the ocean for studying
remote sensing and viewing from space -now unmanned vessels also
lithosphere
ridged
The Earth's Heat Budget
see notes
3 types of Meteorites
stones- 93% achonderites/chonderites irons- 6% Fe + Ni alloys stony irons - <1%
what is a trench
subduction of one plate under another - submarine volcanoes on either side
Latent heat -
temperature change undetected by thermometer Involved in the change of physical state of water o Latent heat of fusion (melting) - add 80 calories to change 1 gram of water 1ºC
o Water vapor
weighs less than nitrogen and oxygen
• Inter-tropical convergent zone (ICTZ)
(ICTZ)
alvin
-research submarine
o Polar front
- cold air and warm air moving in opposite directions
Summer •
- wet season
Ferdinand magellan
-Portuguese explorer navigated the globe for the first time -his crew killed him in indonesia because he was a shit guy -only 3 of his ships returned
mercury
-covered in craters -surface is silicate rock -has no atmosphere -hot on one side and cold on the other -high density small size
what drives plate tectonics
-thermal convection of the "plastic" rocks of asthenosphere which drag along the overlying lithosphere plate -gravity pulls the submerging plate downwards
WHY STUDY OCEAN BASINS?
-they are the largest structures on the the surface planet -They are major repositories for sediments and centers of fluid rock interactions -They are our major reservoirs of hydrocarbons and metals -They are the most efficient records of the evolution of life on our planet and host to all the oceans
mars
-twice earths distance from sun -water is mostly in permafrost in the southern and northern cap -atmosphere is CO2 -Rover Expedi on indicate sulfates in soils
Charles darwin
-was 18 when he left for 4 and a half years the challenger- boat with steam engine -- took a 4 year voyage around the world investigating everything -measured water temperature -water solubility -sample the sea floor and much other discovered over 4000 new species of animals that no one has ever seen before -they documented all of this in a series of books
how does this relate to the oceans
-weathering brings components to the ocean -hydrothermal alteration and volcanism both add and remove components from the sea water
The Early Molten Earth—Heat sources:
1. Gravitational compaction 2. Impact energy converted to heat 3. Heat from radioactive decay -was once completely molten and separated layers by density
which country has the longest coastline of any' country with 15 percent of the world's coastlines.
Canada
eratosthenes map of the world
He was the first person to use the word "geography" and invented the discipline of geography -and longitude and latitude
• what hapens when air is compressed
Heats up
• is humud air less dense then dry air
Humid air is less dense than dry air at the same temperature
hot spots
Mauna Kea, an inactive volcano on the island of Hawaii, is actually the tallest mountain -linear mountains in the middle of the plates -further proof of plate techtonics -size of islands gets smaller
what is Earth's longest mountain range
Mid-Ocean Ridge—it is four times longer than the Andes, Rockies, and Himalayas combined.
Converging boundaries
Ocean-Continental (oregon) (ocean crust goes down) Ocean-Ocean (japan) Continental- Continental (himalayas)
The Gaia hypothesis
Without life, earths atmosphere should have about 98% CO2 (like Venus). 1. Phytoplankton (and much later plants) removed CO2 from the atmosphere - their activity is related to CO2 concentrations. 2. Bacteria generate organic acids which accelerate weathering (and CO2 removal) 3. There is no O2 in volcanic gases so this had to come from a different source
• Incoming and outgoing
are balanced
• Low pressure -
ascending air ***see slides
AKA Doldrums -
is the area encircling the earth near the equator where the northeast and southeast trade winds come together
why is the Budget variable
because Earth's circulation around the sun is inclined -o Seasonal solar input -o Receive different amount of radiation during different seasons
• High pressure -
descending air ***see slides
Winter -
dry season
Pacific basin
fast spreading
Phoenicias
first to move around -first to make maps
• Outgoing radiation -
heat - long-wave radiation
• what does circulation redistribute
heat - what drives circulation
• warm air
holds more water vapor than cold air
What drives circulation?
• Convection current o Warm air rises, cold air sinks • Coriolis Effect
Earth's atmosphere and ocean are intimately intertwined
• Global weather patterns
Components of seawater
• Majority is chloride and sodium • Salinity = total dissolved
Air
• Oxygen + nitrogen + water vapor (up to 4%) - residence time = ~4 days
Heat and temperature
• Water can resist change in temperature in the absence or presence of heat • o o Latent heat of evaporation - add 540 calories o Need to add more heat (calories) but no change of temperature o Remove calories to change state in other direction • Sensible heat - will raise the temperature and can be felt
Water and heat
• Wide range of temperature variations • Huge heat transfer from equator to poles • Heat properties causes earth's great storms
• Air rises and expands
→ cools
the early atmosphere
-carbon dioxide -sulphuric acid -ammonia -methane -poisonous to modern life -no free O2 -contained by basic elements of life : carbon, oxygen, nitrogen, sulfur, and hydrogen
how was a a dry earth - MOON- created
-created by a impact of a very large bolide that hit the earth and threw material out then the material condensed and formed a new planet that was in the gravitational pull -interior was molten -moons surface cools creates crust -large impacts create basins -basins flood with lava to create maria
pillow lava
-extrusion of the lava under water, -no sediment on these pillow lava because they are young
where does the oldest crust and thickest sediment occur
-farther away from the ridge
longitude lines
-for every 15° that one travels eastward, the local time moves one hour ahead -travelling West, the local time moves back one hour for every 15° of longitude. -Therefore, if we know the local times at two points on Earth, we can use the difference between them to calculate how far apart those places are in longitude, east or west. -cook created it -world is 360˚ with 24hrs -base longitude line is 0˚ at grenich -if they are at a place that is 1pm and the local time in grenich is 12pm, they have traveled 15˚ east
mid ocean ridge
-from diverging plates -axial rift at center (no sediment)
venus
-full of clouds -also many craters -CO2 rich clouds cause runaway greenhouse effect -radiation trapped on surface -almost same size and density as earth -small amount of heavy water
What makes the earth unique?
-has a ocean and no other planets do -It is the only terrestrial planet with an ocean -first ocean away from the sun with a moon
prince henry the navigator
-he wanted people to take the ships from Portugal and travel to india and asia -
chinese ships
-invented the stern router -compartmentalization -invented the compases -regarded themselfs as the center of all knowledge sent a troop around the indian ocean -sharing knowledge
Giant (Jovian) planets
-jupiter -neptune -uranus -sater very big but not very dense
ocean-ocean collision
-older plate subduct the younger plate -deep trench forms -earthquakes -island arc volcanoes - sub-ducted crust partially melts
earthquakes sizmic waves
-pressure waves ( p waves ) travel faster than shear waves (s waves) and surface waves travel slower than both -s waves dont travel in liquids very well p- push or pull s- back and forth L surface waves- circular motion
what drives plate tectonics
-push - hot material rising from depth to the surface pushing plates apart -pull- the denser plate gets pulled down by gravity -difference in density is what produces plate tectonics
connent-connent collision
-shallow earthquakes over a broud area - continental lithosphere too buoyant to descend into the mantle -instead, gets uplifted, thickens, no volcanoes but still some melting results in plutons (intrusions)
the last things to come out when the temperature is very low
-the stuff oceans are made of -ice
So, from where did the original ocean come?
1.Outgassing of the original material that also included a small portion of meteorites 2.These volatiles included those we see coming from volcanoes, namely H2O, CO2, H2S (no O2), plus N2 and HCl 3. Condensation of H2O and some of the CO2 and HCl into the oceans, in conjunction with fixing of H2S and CO2 in soils, plus N2 and CO2 in the atmosphere 4. Maintenance of the surface temperature by gases in the atmosphere such that the water was liquid, and then.......
the swiss
1950 - the swiss built a vessel that went to the sea floor -went to the bottom of the sea floor
How many oceans are there on earth
5 pacific atlantic indian arctic southern all have different temps and chemistry but are all conected
how much of earth does the ocean cover and what percent of water on the earth
71% 96%
what percent of earths carbon is in the ocean
96% mostly deep ocean
Why no runaway greenhouse on earth
What factors can reduce atmospheric CO2 concentrations? - Weathering of silicate minerals - Life
we know the structure of the earth because we see the
area where there are no p waves and the areas with no s waves
the 4 outermost planets orbitals (nice model)
as they are rotating around they (jupiter and saturn) got close together bringing a massive amount of gravitational pull changing the orbit of the outer planets (neptune and uranus) nocking them into the icy debris spreading the debris into the inner solar system
the royal society gave a prize to whoever made a smaller cock
because the big one did not work on the boats -john harrison created the watch (a small watchmaker) - a large prize was given to him on his death bed
how is our magnetic field is produced
by the liquid inner portion with the solid portions
density
composition, temperature, pressure -liquids are not compressible so density stays the same -increases at higher pressure
features of ocean basin
continent continental shelf continental slope continental rise abysse plane ocean ridge - divergent plate boundary abysse hill trench - converging plate margins volcanic arc
ashenosphere
deformable, capable of flow
how do we study past oceanographic conditions
deposits that formed from sea water
the church
didn't like the maps because it went again there beliefs
what causes the convection of mantle
differences in density causes the convection -when material is moved up to the surface something needs to move down to take its place
how do we know about the deep earth
direct sampling (melts) remote sensing
3 kinds of plate boundaries
divergent convergent transform
how do they find the magnetic trend
drag a manometer behind a boat to find the magnetic trend
how do they direct sample
drilling logging, dredging and hand picked (computers cant judge),and direct samples of the waters are taken
origin of a solar system (chemical condensation sequence model)
exploding super nova 1. large nebula begins to condense, triggered by nearby super nova 2. explosion supplies debris and 99% gas and 1% rock 3. most of the material is in the center (protosun) 4. spin slows because of debris 5. hot environment near the sun allows condensation of terrestrial planets 6. cooler regions away from sun permit giant less dense planets
how do you figure out latitude
find the north star b/c it doesn't move -find the big dipper -follow the line of the two side stars to find the north star
the ancients- Egyptians greeks
focused on rivers staid inland
first map
had a grid
Harry Hess, who discovered guyots and proposed theory of seafloor spreading in 1960
he saw that there were these huge mountain ranges -and hot water coming out of areas
terrestrial planets
inner planets -mars -earth -venus -mercury
as you move farther from the sun what happens to the planets axis of rotation
not all spin perpendicular
why is mars red
red because the surface is covered in iron oxide
james cook
scientific expeditions -dietitian -sailor -navigator -save meet in salt -people started getting scurvy -got barrels full of limes the charts he made were used right up to 100 years ago he figured out how to find out longitude
features of deep ocean basin
see class
how would they find the centre of the earth
shadows
theary of sea floor spreading
shown by symmetrical magnetic strips around spreading center and existence of transform faults
mid atlantic ocean basin
slower spreading
inner core
solid
Condensation sequence model
take the hot dust and begin to cool it --first things that drop out are gases -things will back react or keep precipitating out
unless the earth is expanding at a substantial rate
there must be CONVERGENT plate margins as well as Mid-Ocean Ridges
Polynesians
they would populate a island and would overpopulate untill they kept moving and found the hawaiian island -invented catermeraines
why no oceans on mars
too far away from the sun to maintain temperatures
why cant venus have a ocean
too hot b/c of green house and closeness to the sun
Geochemistry and Sedimentology
use rock record to see if sea water, refs, nutrient cycle, and temperatures have changed
what happens when waves go through a new density
when you hit another density the wave refracts for p waves
westerly wind
wind from the west
when you sailed to port of alexandria in Egypt
you had to bring a scroll of your travels -to build information and maps
Water molecule
• 105º separation angle • bivalent molecule • very strong, polar bond
ocean continental collisions
• Denser oceanic plate plunges beneath connental plate -causes earthquakes -melting temperature is lowered due to water -volcanic mountains
To form an ocean, need:
• source of water • limited range of surficial temperatures • correct range of surficial pressures • must be constant throughout time • this requires very special circumstances!! pressure and temp must be constant
What is the evidence for plate tectonics? (alfred wagar)
• structure of the earth-it is not homogeneous as we have seen • distribution of past life forms on distal continents and fit of the continents (first noticed in 1873) • spreading centers and symmetrical ages of oceanic crust around them • distribution of earthquakes and mountain ranges • distribution of hot-spots
the modern atmosphere
•78% nitrogen •21% oxygen •1% argon •0.03 carbon dioxide