Who proposed the theory of continental drift? |
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Alfred Wegener |
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Which of the following concepts was developed earliest? |
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continental drift |
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How old are the fossils of the reptile Mesosaurus found in Africa and South America
that suggest the two continents were once together? |
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about 300 million years old |
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When was the theory of plate tectonics developed? |
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1960s |
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Where is new lithosphere created? |
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divergent plate boundaries |
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Where does volcanism occur? |
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convergent plate boundaries and divergent plate boundaries |
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Where are the world's highest mountain ranges created? |
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Convergent plate boundries |
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Which type(s) of plate boundaries indicate(s) the direction of relative plate motions |
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transform fault boundries |
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New lithosphere is created ____________. |
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at mid-ocean ridges |
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What type of plate boundary is shown in the diagram? |
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a subduction zone |
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Which of the following locations could be represented by the diagram? |
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the west coast of South America |
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In which ocean are most of the world's convergent plate margins located? |
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Pacific Ocean |
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The east coast of North America is __________. |
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not a plate boundary |
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Which of the following is associated with a divergent plate boundary? |
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earthquakes
volcanism
rifting
all of the above |
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Which of the following is a divergent plate boundary? |
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the Mid-Atlantic Ridge |
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At what type of plate boundary do the deepest earthquakes occur? |
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convergent |
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Approximately how deep (below sea level) are the deepest deep-sea trenches? |
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10 km |
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Which of the following is not associated with convergent plate boundaries? |
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spreading centers |
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Which of the following is a type of convergent plate boundary? |
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subduction zone |
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Which of the following mountain ranges formed as a result of ocean-continent
convergence? |
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the Andes |
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When a deep-sea trench is located next to a continent, where would you expect to find
active volcanoes? |
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on the continent side of the trench |
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What plate is subducting beneath southwestern Canada and the northwestern United
States? |
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the Juan de Fuca Plate |
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The west coast of South America is __________. |
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a convergent plate boundary |
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Which of the following is an example of a transform plate boundary? |
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the San Andreas Fault |
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What type of plate boundary is parallel to the direction of plate movement? |
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transform plate boundary |
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Which of the following mountain ranges is the product of continent-continent
convergence? |
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the Himalayas |
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The North American Plate is bounded by ______ plate boundaries. |
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convergent, divergent and transform |
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Which of the following can be used to determine the rates of plate motion? ( )
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astronomical positioning seafloor magnetic anomalies global positioning system
D) all of the above |
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The questions refer to this cross section, which depicts magnetized oceanic crust at a spreading
center. The “+” symbol indicates positive (normal) magnetic anomalies; the “–” symbol
indicates negative (reverse d) magnetic anomalies.
How fast are points C and D spreading apart from each other? |
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about 100 millimeters/year |
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The questions refer to this cross section, which depicts magnetized oceanic crust at a spreading
center. The “+” symbol indicates positive (normal) magnetic anomalies; the “–” symbol
indicates negative (reverse d) magnetic anomalies.
“Normal” magnetized crust at the spreading center formed during the ________ epoch. |
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Brunhes |
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Modern seafloor spreading rates range from _________. |
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2 to 15 centimeters per year |
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What two scientists related the positive and negative magnetic bands on the seafloor to
seafloor spreading? |
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F.J. Vine and D.H. Mathews |
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Which of the following is commonly used to determine the age of seafloor samples
recovered by the deep-sea drilling project? |
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foraminifera fossils |
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Which of the following plates is moving the fastest? |
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the Pacific Plate |
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On a map of the seafloor, the boundaries between normally magnetized oceanic crust
and reversely magnetized oceanic crust are called __________. |
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isochrons |
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When was the supercontinent of Pangaea assembled? |
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approximately 250 million years ago |
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How old are the oldest rocks on the ocean floor? |
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about 200 million years old |
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The oldest continental rocks are __________ than the oldest oceanic rocks. |
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much older |
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Isochrons on the seafloor are roughly __________ the ridge axis along which they were
created. |
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parallel to and symmetic about |
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Why are isochrons on the Pacific seafloor more widely spaced than isochrons on the
Atlantic seafloor? |
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the pacific seafloor formed at a faster spreading rate than the Atlantic seafloor |
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What ocean used to lie between Africa and Eurasia and was the ancestor to today's
Mediterranean Sea? |
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Tethys |
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When did the supercontinent Pangaea begin to break apart? |
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about 200 million years ago |
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Pangaea split into two continents: Laurasia, made up of the northern continents, and
______, made up of the southern continents. |
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Gondwana |
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When did India begin to collide with Asia to form the Himalayas? |
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about 50 million years ago |
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Compared to slower moving plates, faster moving plates are bounded by a greater
proportion of __________. |
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subduction zones |
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What drives plate tectonics? |
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mantle convection |
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Which of the following forces is important in driving plate tectonics? |
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A) the pulling force of a sinking lithospheric slab
B) the pushing force of a plate sliding off a mid-ocean ridge
C) the suction force of a retreating subduction zone
D) all of the above |
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How deep are plates subducted? |
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2900 km |
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Regions of intense localized volcanism such as Hawaii form above plumes of fast-rising
material that originate in the __________. |
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deep mantle |
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The Hawaiian volcanoes are __________. |
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not located at a plate boundary |
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The Earth's lithosphere is broken up into approximately _____ large plates. |
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12 |
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New oceanic crust is created at ________. |
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mid-ocean ridges |
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Shallow focus earthquakes are associated with which type of plate boundary? |
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A) divergent
B) convergent
C) transform
D) all of the above |
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Mid-ocean ridges are also referred to as _________. |
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spreading centers |
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An island arc forms when there is __________ convergence |
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ocean-ocean |
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The convergence of the North American Plate with the Juan de Fuca Plate forms the
______ subduction zone. |
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Cascadia |
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Mount St. Helens is part of the ____________. |
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Cascade Range |
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The Great Rift Valley of East Africa is an early-stage _________. |
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divergent boundary |
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The Appalachian Mountains formed from an ancient ____________ plate boundary. |
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convergent |
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Oceanic crust that records negative magnetic anomalies formed when the Earth's
magnetic field was ___________. |
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reversed from what it is today |
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Astronomical positioning measures points on the Earth's surface relative to ________. |
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the position of fixed stars |
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If the position between antennas on two plates moving away from each other changes by
5 mm/yr, then each plate is moving at approximately ______. |
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2.5 mm/yr |
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Rhodinia is a supercontinent that formed __________. |
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before Pangea |
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Fifty million years in the future geoscientists predict the east coast of North America
will be _____________. |
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a convergent plate boundary |
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The main type of plate boundaries are (proper names only): __________. |
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convergent, transform, divergent |
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What kind of plate boundary defines the eastern edge of the plate we live on here in the
United States? |
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mid-ocean rift |
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How do we determine absolute direction of plate movement over millions of years? |
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with seafloor isochrons |
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__________ are the most extensive mountain ranges on Earth today. |
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mid-oceanic ridges |
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Who first described world tectonics in terms of rigid plates? |
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Tuzo Wilson |
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Who first proposed the three different kinds of plate boundaries widely accepted today |
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Tuzo Wilson |
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Which of the following locations is least likely to have active volcanoes? |
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transform fault |
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How many major plates cover the Earth's surface? |
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12 |
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Which of the following plates is the largest? |
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A) Cocos Plate
B) Indian Plate
C) North American Plate
D) Pacific Plate |
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Which of the following plates contains only oceanic crust? |
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Nazca Plate |
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Who first suggested that the Earth's surface might be a fragile shell resting on fluid? |
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Alfred Wegener |
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