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47 Cards in this Set
- Front
- Back
lithosphere:
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-all crust + upper rigid part of mantle
-cool rigid shell |
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what is the lithosphere composed of?
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basaltic (and mantle are same)- Fe (iron) O2 (oxygen) Mg (magnesium) Si (silicon)
granite- O2, Si, Al (aluminum) |
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what is the importance of understanding the lithosphere?
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-helps explain plate tectonics and continental drift
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where are all the places vocanism is found in the ocean?
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mid ocean ridge, seamounts, table mounts, hotspots (mantle plumes), ocean trenches (volcanic arc), abysill plains (abyssil hills)
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why is the oldest ocean basin only 2 my?
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because all the other crust has been subducted inder the lithosphere
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isostacy:
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up and down movement of crust
-result of lithosphere floating on plastic like asthenosphere |
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why is the isostatic adjustment important?
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-provides evidence for movement of tectonic plates because if the continents can adjust themselves vertically then they must not be firmly fixed
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what is the relationship between transform faults and fracture zones?
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transform faults create fracture zones at the MOR
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curie point:
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(hardening) when this happens the magnetic rocks become fixed in the diection of earths magnetic feild (magnetic dip inclination)
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magnetic polarity reversals:
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creates magnetic anomilies: alternating identical stripes of reversed nmagnetisms in ocean floor
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isostacy:
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up and down movement of crust
-result of lithosphere floating on plastic like asthenosphere |
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why is the isostatic adjustment important?
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-provides evidence for movement of tectonic plates because if the continents can adjust themselves vertically then they must not be firmly fixed
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what is the relationship between transform faults and fracture zones?
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transform faults create fracture zones at the MOR
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curie point:
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(hardening) when this happens the magnetic rocks become fixed in the diection of earths magnetic feild (magnetic dip inclination)
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magnetic polarity reversals:
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creates magnetic anomilies: alternating identical stripes of reversed nmagnetisms in ocean floor
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abyssal hill:
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volcanic features on th ocean floor that are less than 1000 m (.6 miles) which is the minimum height of a seamount
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seamount:
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tall volcanic peaks
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guyot:
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tall volcanic peaks with a flat top from waves
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Moho:
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-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 |
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How are the hypothesis of contiental drift and sea floor spreading reconciled by plate tectonics?
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it describes as a whole how the outermost portion of the Earth moves
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what property in the magnetic record found in oceanic crustal rocks that gave rise to sea floor spreading?
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magnetic anomalies
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Why are there earthquakes less than 10 km at MOR but as deep as 670 km at trenches?
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because the seismic activity occurs at shallow areas on the MOR and deep within the trenches
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HOw are heat flow, age of rock, distance from MOR and depth of ocean all related?
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-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. |
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how are the velocities of tectonic plates determained?
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rate of sea floor spreading? which is different at different parts of MOR
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why are abyssal plains so flat and featureless?
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-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 |
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how much of the earths surface is covered by ocean?
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70.8%
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Pacific Ocean:
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worlds largest covering over half the ocean surface
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Atlantic Ocean:
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half the size of the Pacific
-separates the old world (Europe. Asia and Africa) from the New World |
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Indian:
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slightly smaller than atlantic
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Artic Ocean:
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smallest and shallowest
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Antartic Ocean:
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portion of the Pacific, Atlantic and Indian
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Average depth of ocean:
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3729 meters (12,234 feet)
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average height of the continents:
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840 m (2756 ft)
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distance to sun:
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150 mil km (93 mil miles)
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to moon:
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3840 km (220,000 miles)
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speed of light per sec:
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300,000 km per second
186,000 mi per second |
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density:
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amount of mass per unit volume
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light year:
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how far light travels in a year
-9.8 trillion km -closest star is four lightyears away |
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circumfrence of earth:
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40,000 km at equator
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age of universe:
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13.7 billion years
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age of solar system:
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5.5 billion years
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age of sun and earth:
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4.6 billion years
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age of ocean:
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200 million years?
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where does earths water come from?
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out gas, in comets?
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big bang:
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13.7 bil years ago
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chemical comp of mantle:
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O2, Si, Fe, Mg
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chemical comp of core:
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Fe (90%) Si, Ni (nickel), S (sulfer)
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