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23 Cards in this Set
- Front
- Back
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What evidence did Wegener use to estimate the time of Pangaea's break up?
a. fossil data b. coal deposits c. ocean-floor topography d. magnetic isochrons |
a.
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Harry Hess' theory of __________ explained how ocean crust is generated and destroyed.
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seafloor spreading
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What is thought to be the driving mechanism of plate movement?
a. volcanoes b. conduction of heat in the mantle c. continental drifting d. convection currents in the mantle |
d.
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Where do tectonic plates interact?
a. at plate centers b. at mid-ocean ridges c. in deep-sea trenches d. at plate boundaries |
d.
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Rocks close to mid-ocean ridges are __________ rocks far from mid-ocean ridges.
(older than, younger than) |
younger than
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The thickness of ocean sediments that are close to a mid-ocean ridge is __________ the thickness of ocean sediments that are far from mid-ocean ridges.
(more than, less than, same as) |
less than
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What is the name of Alfred Wegener's hypothesis about moving landmasses?
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continental drift
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How are the convection currents set in motion?
a. slab push and ridge pull b. the heat from radioactive decay c. spreading mid-ocean ridges d. slab push |
a
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When a divergent plate boundary forms on continents, a __________ forms.
a. mid-continent ridge b. rift valley c. volcano d. crater |
b
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The __________ states that Earth's crust and ridged upper mantle are broken into plates that move at different rates and in different directions.
a. hypothesis of continental movement b. theory of plate tectonics c. hypothesis of continental drift d. theory of seafloor spreading |
b
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A place where two plates slide laterally past each other is called a __________.
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transform boundary
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Wegener proposed that the continents were __________.
a. formed at deep ocean trenches b. floating on top of oceanic crust c. formed at mid-ocean ridges d. plowing through oceanic crust |
d
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Why did Wegener think that the Antarctic continent had been closer to the equator in the geologic past?
a. existence of coal beds b. existence of volcanic rocks c. existence of the Transantarctic Mountains d. evidence of fossil fish |
a
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What two topographic features of the ocean floor were discovered only with the use of sonar?
a. mid-ocean ridges and earthquakes b. mid-ocean ridges and deep-sea trenches c. shallow-sea trenches and volcanic islands d. volcanic islands and mid-ocean ridges |
b
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What is the study of Earth's magnetic record?
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paleomagnetism
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Which type of information was NOT collected by Wegener to support his continental drift hypothesis?
a. glacial deposits b. fossils c. seafloor magnetic data d. rocks |
c
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What evidence did Wegener use to estimate the time of Pangaea's break up?
a. ocean-floor topography b. magnetic isochrons c. coal deposits d. fossil data |
d
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What can form when two continental plates collide?
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fold mountains
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Formed when an ocean basin between converging oceanic and continental plates is entirely subducted.
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continental-continental convergent plate boundary
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Where are most divergent boundaries found?
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on the seafloor
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Convergent boundaries are classified according to the what? Name the types.
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type of crust involved. ocean-ocean, ocean-continental, continental-continental
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Which of the following landforms results from divergence of continental crust?
a. a mountain range b. a rift valley c. a deep-sea trench d. a long fault |
b. a rift valley
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Which of the following best describes what happens when an oceanic plate converges with a continental plate?
a. a deep-sea trench and an island arc form. b. both plates become fractured, and a series of long faults form on the surface. c. both plates crumple and a folded mountain range forms. d. a trench and a mountain range with many volcanoes form. |
d.
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