OCEANOGRAPHY

geological oceanography

"history" of the ocean, plate tectonics, stratiography

Benjamin Franklin (1770)

(deputy postmaster for the american colonies) learned that shops taking the northerly route from europe to the colonies took two weeks longer than ships that sailed the "longer" southerly route. Coming from the north meant that ships were sailing against a great current. He and Timothy Folger created an accurate map of the gulf stream current in 1770

Minoan civilization

(in crete, on agean sea around 3000 BCE) used boats for transport, trade, defense and conqest

Reef process

1. Fringing reef, adjacent to island 2. Barrier reef, volcano sinks and reef grows upward 3. lagoon, seperates barrier reef and island 4. Island sinks and leaves on the atoll

Four types of marginal seas

1. shallow seas where contintental crust is submerged 2. long narrow seas where continents are breaking apart, 3. seas between continents that are moving toward a future collision and 4. back-arc basins behind subduction zones

systematic study of the oceans began in

1768 (Captain james cook ..voyages to explore pacific ocean)

The Beagle

1831, 5 year voyage of discovery. goal was to complete a hydrographic survey of the patagonia and tierra del duego coastal regions to improve maps used by ships sailing between pacific and atlantic oceans around the tip of s. america. (also visited glapagos islands off the coast of peru), Charles Darwin was on the journey

The Challenger

1872-1876, discovery of deep sea life and birth of modern oceanography. the 6 scientists on the HMS challenger sailed world's oceans to study physics, chemistry, geology and biology of the world's oceans. (british vessel) sailed 127, 500 km across oceans

Law of the Sea Conferences

1958 and 1960, UN met to establish international uniformity in the ownership and access rights of nations to the resources of the oceans. 80 nations in attendance. Established a "zone" (22km wide) that nations could fish in and that high seas are free for all, also=tried to define the right to own seabed and sub seabed minerals on the continental shelf of coastal regions. Exploitation was an issue

The common heritage princicple

1967, Dr. Arvid Pardo. ocean floor outside off national jurisdiction should be reserved for peaceful uses and its resources should become the common heritage of mankind (this also applies to the atmosphere, antartica, tropical rainforests) earths resources belong to all its people, we have the right and responsibility to protect the global environment and its resources wisely

Third UN law of the Sea Conference

1973, signing of the Law of the Sea treaty. (US voted against, only major nation who has not ratified it but does recognize it as international law) Covers: 1. an exclusive economic zone (EEZ) 2. procedures for drawing ocean boundaries for nations closer than 740 km 3. right for free or innocent passage guaranteed for all vessels outside the territorial seas and trhough straits 4. rules for exploiting minerals

First visit to a hydrothermal vent by the submarine Alvin

1977, discovery of an ecosystem (based on chemosynthesis) sustained hundreds of species prviously unknown

Inner Core

2.8 g/cm3

Asthenosphere (Upper Mantle)

250 km, plastic material, close to melting point, flows without fracturing

Lower Mantle

250-290 km

Pure water has a density max of

4 degrees C

Circumference of Earth through N and S poles=

40,032 KM

Lithosphere

5-90 Km (continental crust) 100 km (oceanic crust)

Outer Core

Av density= 9-10 g/cm3

1430

Azores (in atlantic ocean) were discovered

1416

CANARY ISLANDS EXPLORED

15-19-1522

Ferdinand Magellan's expedition to circumnavigate the world (he died during it)

Greatest navigators in history?

Polynesians

in 6th century BCE...

Pythagoras declared Earth to be spherical

1298

Vasco de Gama rounds the tip of Africa

Indian Ocean

Youngest Ocean

The 2000 years following the Phoecian era was...

a lapse in sea exploration, possibly due to dark ages

Bones of marine fishes discarded by stone age people that have been found in settlements in europe...

are from 40,000 BCE

Superplumes

areas under which mantle upwelling is thought to occur, large areas of mantle material that swell upward from core-mantle boundary

Atoll

base of nearly circular coral reef

Poseidonius's incorrect measurement of the earth's circumference led...

christopher columbus to believe he had arrived in asia when he arrived in the americas

Upper mantle looses heat through...

conduction through earth's cooler crust

hydrosphere

consists of all water in the lithosphere that is not combined in rocks and minerals oceans and freshwater, over 2/3 of earth's surface)

Seawater composition

contains almost all naturally ocurring elements, organic compounds and dissolved gasses

Abyssal plain/ hills

continental rise meets ocean floor wihich then becomes the plain or hills

Deep - ocean trench

continental slope extends into this

Sea trade with europe, indea, east africa and southeast asia in the..

dark ages

1400's (mid/late)

dawn of european ocean voyages

Earth's layers are characterized by

density

The Truman proclamation

descision after world war 2 in 1945, that a country can utilize the subsoil and seabed of the continental shef beneath the high seas but contiguous to the coasts of the u.S (183 m of water) Caused controversy and inspired other nations to claim various control over waters near them

Salinity

deteremined by the mesure of electrical contdctivity

High salinity brines were

discovered in 1964 and 65 in the bottom of the red sea

seismic tomography

earthquake waves used to study the eath's internal structure in detail

Passive Margins

edge of a new continent formed at a mature continental rift valley. depth and width can be influenced by isostatic changes.

Water aborbs

electromagnetic radiation, lgiht can penetrate up to several hundred meters into clear ocean waters and is energy source (photosynthesis)

atmosphere

envelope of gasses surrounding atmosphere and hydrosphere -78% nitrogen and 21% oxygen

Monsoons

europeans used monsoons to help their voyages across the sea to india/etc. (wind changes)

Captain James Cook

explored pacific ocean, brought chronometer to sea (could measure longitude precisely and improved existing maps), made soundlings, accurate measurements of water temperature, currents, wind speed and directions and documented occurrence/general characteristics of coral reefs

Continental shelf

extension of continent itself,

Ptolemy

famous ancient mapmaker who lived around 15o BCE (His maps were acccurate latitudinally but not longitudinally)

Chronometers

first developed in 1760's, could keep accurate time on a ship

Water has high

freezing and boiling points and can be present at solid, liquid and vapor phases and high surface tension

Charles Darwin

his observations on the beagle were the basis for his book the expedition of the Origin of species (evolution=the major finding but also made other major findings such as formation of coral atolls, finding fossils to conclude that the andes mountains had originated in the sea=continents not permanents and must move vertically)

Discoveries conducted on The Challenger

hundreds of observations of coean temp, over 100 dredge samples of rocks/sediment from seafloors, over 150 open water net trawls for fishes and organisms, samplings of seawater readings of current velocity and meterological conditions, visual observations of fishes, marine mammals and birds

New oceans may form

in a location where the temperature of the mantle below the continent becomes elevated and density increases, crust thrust upward, forms a dome, stretches the crust and causes fractures that extend outward from center of dome. As fracture widens, the lithosphere beneath the bulge begins to melt. Eventually, blocks of crust break off and slip down into the rift valley formed by the fractures. This occurs unevenly along the length of the rift. mantle has areas where its material is upwelled. Magmatic rocks are denser than continental, the rift valley floor sinks untel below sea level. rift fills with seawater and becomes arm of ocean. Then becomes a marginal sea

oceanography definition

interdisciplinary study of ocean and its inhabitants

Atlantic Ocean

is widening as lithospheric plates move apart at the Mid-Atlantic Ridge, has few islands and broad continental shelves

Magmatic arc volcanoes

islands form on the nonsubducting plate of a magmatic arc, islands are heated by rising magma

Pacific Ocean

largest and oldest ocean. ringed by subduction zones, has many volcanic islands and atolls formed at hot spots and magmatic arcs, has a relatively low sediment covered seafloor

Sound is absorbed

less effectivitly by water than light. travels long distances, used to measure depth and seafloor topography

Isostacy

lithosphereic plates float on the asthenosphere at levels determined by their density

downwelling

mantle has areas where its material is downwelled

upwelling

mantle has areas where its material is upwelled, is heated by earth's core and is slightly less dense

chemical oceanography

mapping dist. of chemicals in seafloor sediment and seawater (ex. salinity, oxidization etc)

biological oceanography

mapping dist. of plant/animal species

physical oceanography

mapping distribution of salt content, temperature and currents

First boats

may have been made by homo erectus (our predecessor) in Flores, Indonesia about 750, 000 years ago. To reach that area, they had to have crossed a wide strait which was a barrier for migration for most other species

Soundlings

measurements of water depth (lead attached to rope)

topographic features

mountain ranges, plains, depressions and plateaus in the ocean floor

convection

movements of lithosphereic plates are thought to be driven by heat energy transferred through the mantle by convection

Convection cells

nature and locations are unknown, two types: shallow and deep.

Shoals

number of fish swimming together

45,000 years ago, ..

ocean voyage and trade were beginning to expand in the Meditterranean and large islands in the far western pacific/micronesia were colonized

Wegeners 1912 theory

of continental drift (evidence gathered from the deep sea drilling program)

Shelf break

offshore from the continental shelf

Argo floats

one of autonomous robot measuring devices

Colonization in micronesia and western pacific were due to ..

outrigger canoe

Matthew Fontaine Maury

pblished the physical geography of the sea ( a volume on wind and current data) in 1855, has been called the "Father of oceanography"

Maganese nodules

potential mineral resources of deep oceans, rock concretions on the sea bottom formed of concetric layers of ireon and manganese hydroxides around a core

Pytheas

proposed method of determining latitude with the north star/horizon & that tides were caused by the moon

other fields of oceanography

remote sensing, seismology, human interaction, etc.. .

by 1800

seafaring nations had establishes government offices with the primary responsibily for producing charts that could be used by mariners to navigate safely and avoid reefs/shoals

Continental slope

shelf break joins it and it extends to 2-3km

The 5.6 km territorial sea

standard for nations, control over that length of ocean around/near their borders

Polynesians used

stars, winds, wave patterns, clouds and seabirds to navigate

Back-Arc Basins

subducted plate's rate of destruction can exceed a the rate at which the two plates are movine toward each other and the edge of the plate gets stretched which causes a thinnning of the lithosphere at the edge (behind a magmatic arc), generally shallow seas with an ocean floor with lots of sediment eroded by wind and water from magmatic arc

early development of transportation and trade started in ....

the mediterranean (polynesian/micronesian cultures in pacific ocean might have during the same time)

Last 225 million years=

the spreading cycle (Pangea to now)

Artifacts, rock carvings and paintings from cave dwelling people means...

they were using harpoons, fishhooks, net and primitive boats by the late stone age (6000 BCE), first boats came much later

Continental Rise

trench turns into this which then joins the deep-ocean floor

Theories of continental drift and plate tectonics were developed in...

twentieth century

Seamounts

undersea cone-shaped mountains , some have guyots (flat tops)

Eustatic Sea-Level Change

warm and cools periods expand or contract oceans and raise or lower sea leve. happens much faster that isostatic sea level changes

Phoenicians

were a great sea power from 1100 to 850 BCE

Rift Zones

where a continent is being pulled apart

The first human boats were made of...

wood, reeds, animal skins or tre bark. (substances that don't usually survive for study)