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47 Cards in this Set

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lithosphere:
-all crust + upper rigid part of mantle

-cool rigid shell
what is the lithosphere composed of?
basaltic (and mantle are same)- Fe (iron) O2 (oxygen) Mg (magnesium) Si (silicon)

granite- O2, Si, Al (aluminum)
what is the importance of understanding the lithosphere?
-helps explain plate tectonics and continental drift
where are all the places vocanism is found in the ocean?
mid ocean ridge, seamounts, table mounts, hotspots (mantle plumes), ocean trenches (volcanic arc), abysill plains (abyssil hills)
why is the oldest ocean basin only 2 my?
because all the other crust has been subducted inder the lithosphere
isostacy:
up and down movement of crust

-result of lithosphere floating on plastic like asthenosphere
why is the isostatic adjustment important?
-provides evidence for movement of tectonic plates because if the continents can adjust themselves vertically then they must not be firmly fixed
what is the relationship between transform faults and fracture zones?
transform faults create fracture zones at the MOR
curie point:
(hardening) when this happens the magnetic rocks become fixed in the diection of earths magnetic feild (magnetic dip inclination)
magnetic polarity reversals:
creates magnetic anomilies: alternating identical stripes of reversed nmagnetisms in ocean floor
isostacy:
up and down movement of crust

-result of lithosphere floating on plastic like asthenosphere
why is the isostatic adjustment important?
-provides evidence for movement of tectonic plates because if the continents can adjust themselves vertically then they must not be firmly fixed
what is the relationship between transform faults and fracture zones?
transform faults create fracture zones at the MOR
curie point:
(hardening) when this happens the magnetic rocks become fixed in the diection of earths magnetic feild (magnetic dip inclination)
magnetic polarity reversals:
creates magnetic anomilies: alternating identical stripes of reversed nmagnetisms in ocean floor
abyssal hill:
volcanic features on th ocean floor that are less than 1000 m (.6 miles) which is the minimum height of a seamount
seamount:
tall volcanic peaks
guyot:
tall volcanic peaks with a flat top from waves
Moho:
-Mohorovicic discontinuity

-serves as the boundry b/t earths crust and the mantle

-entirely in lithosphere

_uner MOR it also difines the boundary b/t lithosphere and asthenosphere
How are the hypothesis of contiental drift and sea floor spreading reconciled by plate tectonics?
it describes as a whole how the outermost portion of the Earth moves
what property in the magnetic record found in oceanic crustal rocks that gave rise to sea floor spreading?
magnetic anomalies
Why are there earthquakes less than 10 km at MOR but as deep as 670 km at trenches?
because the seismic activity occurs at shallow areas on the MOR and deep within the trenches
HOw are heat flow, age of rock, distance from MOR and depth of ocean all related?
-heat flow is the heat from earths interior relasing to the surface; most of it to the MOR. THe heat flow to deep sea trenches is VERY little

-as the lava cools at the MOR it contracts and subsides fro0m ridge. THe youngest rock is at its axis, but as it subsides and gets further a away from the edge, younger rock is created.
how are the velocities of tectonic plates determained?
rate of sea floor spreading? which is different at different parts of MOR
why are abyssal plains so flat and featureless?
-formed by fine particles of sediment slowly drifting onto the oceanic floor

-over millions of years a thick blanket of sediment is produced by suspension settling

-with enough time these deposits cover most irregularities
how much of the earths surface is covered by ocean?
70.8%
Pacific Ocean:
worlds largest covering over half the ocean surface
Atlantic Ocean:
half the size of the Pacific

-separates the old world (Europe. Asia and Africa) from the New World
Indian:
slightly smaller than atlantic
Artic Ocean:
smallest and shallowest
Antartic Ocean:
portion of the Pacific, Atlantic and Indian
Average depth of ocean:
3729 meters (12,234 feet)
average height of the continents:
840 m (2756 ft)
distance to sun:
150 mil km (93 mil miles)
to moon:
3840 km (220,000 miles)
speed of light per sec:
300,000 km per second

186,000 mi per second
density:
amount of mass per unit volume
light year:
how far light travels in a year

-9.8 trillion km

-closest star is four lightyears away
circumfrence of earth:
40,000 km at equator
age of universe:
13.7 billion years
age of solar system:
5.5 billion years
age of sun and earth:
4.6 billion years
age of ocean:
200 million years?
where does earths water come from?
out gas, in comets?
big bang:
13.7 bil years ago
chemical comp of mantle:
O2, Si, Fe, Mg
chemical comp of core:
Fe (90%) Si, Ni (nickel), S (sulfer)