Oceanography 200

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• 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


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