OCE1001 midterm

approximately what percentage of earth is covered by oceans?

70.8%

what ocean is the deepest on earth?

Pacific ocean

what is the average depth of the worlds oceans?

12,080 feet

what are the four principal oceans plus one?

pacific,atlantic, indian, arctic, and southern ocean or antarctic ocean

the deepest spot in the ocean is deeper than mount everest is high. true or false

true (challenger deep)

could all the continents fit into the space of the Pacific ocean? true or false

true

based on the scientific method, science supports the explanation of the natural world that_____.

best explains all available observations

the age of discovery was the time period in ocean exploration history when ______.

when the western european world realized the vastness of earths water covered surface

when was the age of discovery?

30 year period from 1492-1522

who led the voyage of the Victoria, the first vessel known to circumnavigate the earth?

Ferdinand Magellan; Juan Sebastian del Cano completed the circumnavigation by taking the last of the ships after Ferdinand Magellan's death.

who followed behind Bartholomeu Diaz and continued to india, establishing a new eastern trade route?

Vasco de Gama in 1498

who financed Christopher Columbus and for what reason?

financed by the Spaniards in order to find a new route to the East Indies across the Atlantic ocean

even though Christopher Columbus is accredited with discovering North america (he landed in the caribean and never stepped foot on north america) Who was the first to set foot on North America?

John Cabot in 1497

who was the first to discover the pacific and how did he discover it?

Vasco Nunez de Balboa landed on panama and noticed another large ocean to the west from onto of a mountain

who initiated the circumnavigation of the earth and how did he die?

Ferdinand Magellan, he was killed in the Philippines by the hand of the inhabitants of the island

when and who sailed around Cape Agulhas (southern tip of Africa)?

Bartholomeu Diaz in 1486

who discovered a way to prevent scurvy, and with what food item?

James cook, discovered that a diet containing the german staple sauerkraut prevented scurvy

the GPS system is a tool used for determining surface ____.

location

the most accurate scientific estimation of earths age is based on ____.

radiometric methods of determining the age of meteorites and moon rocks

the cosmological model for the formation of the sun and the res of our solar system is called the

nebular hypothesis

the oceans are believed to have been formed about_____.

4 billion years ago

the early oceans and atmosphere are thought to have come from within the earth by a process called "outgassing". true or false

true

Which of the following statements concerning density stratification is FALSE?

density stratification has caused our Earth to be homogeneous throughout

Of the following, which best describes the physical property of the asthenosphere?

plastic

What physical property determines the order of Earth's layers?

density

The vertical movement of crust to accommodate additional weight or removal or weight is called ___________.

isostatic adjustment

Which gas was absent from Earth's early atmosphere?

oxygen

The naturalist Charles Darwin, who is credited with developing the theory of evolution by natural selection, suggested that the changes organisms display through time were the result of __________.

adaptations to different environmental conditions.

What did Stanley Miller's 1952 experiment demonstrate?

Organic molecules could be created from the materials contained in Earth's early atmosphere and ocean

The subdivisions of the geological time scale __________.

were initially based on fossil evidence, extinctions, and boundaries of sedimentary rock units

Oceans contain what percent of all the water on or near Earths surface?

97.2%

Evidence suggests boat technology was developed approximately how many years ago?

40,000

The first humans from the Western Hemisphere known to have developed the art of navigation were whom?

the Phoenicians

Who were the first people to colonize Iceland?

the vikings

Who discovered Greenland?

Erik "the red" Thorvaldson

Who may have discovered Baffin Island?

Erik "the red" Thorvaldson

Who discovered Newfoundland?

lief Eriksson

What is theory?

A theory is a well substantiated explanation of some aspect of the natural world that can incorporate facts, laws, logic inferences, and tested hypotheses.

What is viscosity?

a measure of a substances resistance to flow

what is plate tectonics?

The outer most portion of earth is composed of a patch work of thin, rich plates that move horizontally with respect to one another.

Pangea

super continent 250 million years ago

paleomagnetism

study of magnetism over geological time

Oceanic-continental Convergence

occurs where two plates converge, and the denser plate is sub-ducted

Oceanic-oceanic convergence

occurs where two plates of the same composition converge in neither plate being sub-ducted

divergent boundaries

plate boundary most closely associated with the formation of new ocean floor

convergent boundaries

found where plates are moving against each other and one plate subduct's beneath the other

transform boundaries

formed where lithospheric plates slowly grind past one another

how often does earths magnetic field switch polarity?

250,000 to several million years

seismic moment magnitude

the scale used to measure earthquake intensities

Panthalassa

huge ocean that surrounded Pangea

what do nearly all igneous rocks contain?

magnetite

magnetite

naturally magnetic iron mineral. particles in magma align themselves with earths magnetic field. they can only align when they're in lava form, once hardened they cannot move.

Basalt

the rock type that comprises oceanic crust. also has the largest concentration of magnetite

Magnetic dip

the degree to which a magnetite particle points into earth. magnetic dip is directly related to latitude.

magnometer

a sensitive device dragged behind a vessel back and forth in an evenly spaced pattern that measures earths magnetic field and how it was affected by the magnetic properties of rocks on the ocean floor

what is the mid-ocean ridge?

continuous underwater mountain range that winds through every ocean basin in the world and resembles the seam on a baseball.

ocean trenches

deepest parts of the ocean floor and resemble a narrow crease trough

subduction

plate bending downward and slowly plunging back into the earths interior

subduction zone

the sloping area from the trench along the downward moving plate

according to the plate tectonic theory, how is new ocean floor created?

new ocean floor is created at the mid-ocean ridge by sea floor spreading and moves off the ridge to eventually be subjected and remelted in the mantle

earthquake

sudden release of energy caused by fault movement or volcanic eruptions

rift valley

a central downward linear depression

rifting

further splitting apart of the land

oceanic rises

gently sloping and fast-spreading parts of the mid-ocean ridge

East Pacific rise

between the Pacific and Nazca plate is a broad, low, gentle swelling of the sea floor with a small indistinct central rift valley. spreads at 6.5 inches per year.

oceanic ridges

steeper-sloping and slower-spreading areas of the mid-ocean ridges

Mid-Atlantic ridge

between South America and African plates is a tall, steep, rugged oceanic ridge that has an average spreading rate of 1 inch per year and stands at 10,000 feet above the surrounding sea floor

hotspots

areas of intense volcanic activity that remains more or less in the same location over long periods of geological time and are unrelated to plate boundaries

Nematath

a chain of extinct volcanoes that is progressively older as one travels away from a hotspot

seamounts

large underwater cone shaped volcanoes

table-mounts or guyots

flat topped underwater volcanoes; unlike anything on land

fringing reef

initially develop along the margin of a landmass, where the temperature, salinity, and turbidity of the water are suitable for reef-building corals

barrier reef

linear or circular reefs separated from landmass by a well-developed lagoon

Atol

as a barrier reef around a volcano continue to subside, coral builds up toward the surface. after millions of years the volcano submerges but the reef continues to grow

Paleogeography

the study of historical changes of continental shapes and positions

continental accretion

the process by which continents are thought to add material such as islands, bits and pieces of continents to create larger landmasses

island arc's are?

convergent plate boundaries

mountains are?

convergent plate boundaries

oceanic trenches are?

convergent plate boundaries

rift valleys are?

divergent plate boundaries

volcanoes are?

divergent plate boundaries

a device used for side scan sonar

Geological Long-range Inclined Acoustical Instrument (GLORIA)

uses high frequency sound waves to measure ocean depth

Precision Depth Recorder (PDR)

when, where and who attempted to measure the oceans depth?

about 85 B.C by a Greek named Posidonius in the mediterranean sea

what is the standard unit of ocean depth?

fathom

used to determine shape and position of boundaries

seismic survey

abyssal clay is what type of phrase?

terrigenous sediment

what are the 3 major continental margins?

1) continental margin

2) deep-ocean basins

3) mid-ocean ridge

continental margin

shallow areas close to continents

deep-ocean basins

deep water areas farthest from land

mid-ocean ridge

composed of shallower areas near the middle of an ocean

passive margins

are embedded within the interior of lithospheric plates and are therefore not in close proximity to any plate boundary (example: east coast of U.S where there is no plate boundary)

active margins

associated with lithospheric plate boundaries and are marked by a high degree of tectonic activity.

what are the two types of active margins?

1)convergent active margins: associated with convergent plate boundaries

2) transform active margins: les common and are associated with transform plate boundaries

what is the measurement of ocean depths and the charting of the shape, or topography of the ocean floor?

bathymetry

continental shelf

generally flat zone extending from the shore beneath the ocean surface to a point at which a marked increase in slope angle occurs

shelf break

is is usually flat and relatively featureless because of marine sediment deposits but can contain coastal islands, reefs, and raised banks. this is what ends the continental shelf

continental slope

lies beyond the shelf break, is where the deep ocean basins begin

submarine canyons

narrow but deep submarine valleys that are v-shaped in profile view and have branches or tributaries with steep overhanging walls (kind of look like canyons made on land by rivers)

turbidity currents

underwater avalanches of muddy water mixed with rocks and the debris