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27 Cards in this Set
- Front
- Back
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What does Plate Tectonics explain? |
earthquakes and volcanic activity (usually happen in concentrated belts) |
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What evidence is there of continents once being connected? |
Mesosaurus fossil remains found on both South America and Africa |
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What happens to rocks that make up the sea floor as you move away from a mid ocean ridge? |
The rocks get older as you move farther away from the ridge |
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Which plate subducts when two plates converge? |
the denser plate subducts under the less dense plate |
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Explain the process of the formation and breakup of Pangea |
Pangea formed when Gondwana moved Northward and converged with other landmasses. Pangea broke up into two seperate landmasses and eventually broke into the shape it is today |
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Compare continental crust and Oceanic crust |
Continental crust is less dense and is mostly basalt Oceanic crust is more dense and is mostly granite |
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What is happening in the mantle at a divergent plate boundary? Convergent plate boundary? |
Divergent: seperating and rising, temp. is increasing Convergent: coming together and sinking, temp. is decreasing |
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What plate boundaries can volcanoes form at? |
divergent or convergent boundaries |
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differences between lava and magma |
Magma is composed of molten rock and is stored in the earth's crust- Lava is magma that has reached the surface of the earth |
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what are the three types of volcanos |
1. Stratovolcano (composite): conical, made of layers of hardened lava flows 2. Cindercone: steep, conical, formed from lava fragments that have been ejected from a volcanic vent 3. Shield: shield-shaped,with a broad base and gently sloping sides that is made of basaltic lava |
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What affects the formation of magma? |
temperature, pressure, and composition |
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Where do volcanoes form? Provide examples |
overs hot spots, divergent boundaries (rifts, mid-ocean ridges), convergent boundaries (subduction zones) |
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What happens to the viscosity as silica content of magma is increased? What is viscosity? |
the viscosity becomes greater -Viscosity: thickness (consistency) |
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Why does Hawaii has many extinct volcanoes and only one active one? |
There is only one volcano over the hot spot. As the plate moves over the hotspot, a volcano will move off and a new one will form |
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What does one seismograph station tell us about an earthquake? How many seismograph stations do we need for an exact location? |
tell the size of earthquake- 3 will give an exact location |
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What is the major cause of earthquakes? |
Plates colliding and other tectonic activites |
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What are P-Waves and S-Waves? Compare the movement of each |
P-Waves: earthquake wave that is the first to be detected, travels the inside of earth- moves in a line like motion S- Waves: earthquake wave that is second to be detected, travels the surface of earth- moves in waves (up&down) |
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What are the names of the surface waves? |
Love and Rayleigh |
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What have we learned about Earth's interior through the study of earthquake waves? |
the outer core is liquid the inner core is solid |
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What is the epicenter? Focus? |
Epicenter: point on earth's surface located directly above the focus Focus: location where an earthquake begins |
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Where do mountains grow when an oceanic crust and continental crust collide? |
on the continental crust |
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example of a mountain range forming where two continental crusts collided? |
the Himilayas |
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Different types of faults |
Normal: hanging wall moves down with respect to the footwall Reverse: hanging wall moves up with respect to the footwall Strike-slip: 2 plates sliding past each other horizontally (San Andreas) |
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three parts of a fold in a folded mountain |
anticline: top of fold (A-shape) syncline: bottom of fold (U-shape) limb: straightish part in between the anticline and the syncline |
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What are grabens? Horsts? |
Grabens- blocks of crust that have dropped between normal faults Horsts: blocks of crust that has moved upward between normal faults |
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What is a continental margin? What does active and passive mean? |
zone of the ocean floor that seperates the oceanic crust from the continental crust Active: sites of tectonic activity (earthquakes and volcanoes) Passive: no tectonic activity |
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What is involved in the formation of fault-block mountains? |
when faults in the earth's crust force some materials up and down, it breaks up into blocks from compression |
