Ch 9 Wegeners continental drift hypothesis stated that

Ch 9 Wegener’s continental drift hypothesis stated that all the continents once joined together to form ____. • a. two major supercontinents • b. two major supercontinents and three smaller continents • c. one major supercontinent • d. three major supercontinents

Ch 9 The supercontinent in the continental drift hypothesis was called ____. • • a. Panthalassa b. Pangaea c. Mesosaurus d. Africa

Ch 9 What hypothesis states that the continents were once joined to form a single supercontinent? • • a. plate tectonics c. continental drift b. seafloor spreading d. paleomagnetism

Ch 9 In the plate tectonics theory, the lithosphere is divided into ____. • • a. 100 major plates b. 7 major plates and many smaller plates c. many small plates, but no large plates d. 50 major plates and many smaller plates

Ch 9 The lithospheric plates move an average of ____. • • a. 5 inches per year b. 50 inches per year c. 5 centimeters per year d. 50 centimeters per year

Ch 9 A tectonic plate consists of ____. • • a. the crust and uppermost mantle b. the oceanic and continental crust only c. the crust and entire mantle d. the asthenosphere only

Ch 9 Which of the following is a geographic example of a transform fault boundary? • • a. the East African Rift valley b. the San Andreas Fault c. the Mid-Atlantic Ridge d. the Andes Mountains

Ch 9 New ocean crust is formed at ____. • • a. divergent boundaries c. continental volcanic arcs b. convergent boundaries d. transform fault boundaries

Ch 9 Which of the following results when divergence occurs between two oceanic plates? • a. seafloor spreading • b. a subduction zone • c. an ocean trench • d. a volcanic island arc

Ch 9 What forms when one oceanic plate is forced beneath another plate? • a. an ocean basin • b. an ocean ridge • c. a subduction zone • d. a rift valley

Ch 9 Deep ocean trenches are associated with ____. • • a. ocean ridge systems b. subduction zones c. transform fault boundaries d. rift zones

Ch 9 • What type of plate boundary is illustrated in Figure 9 -1? • a. transform fault boundary • b. divergent boundary • c. convergent oceanic-oceanic boundary • d. convergent oceanic-continental boundary

Ch 9 Volcanic island arcs are associated with what type of plate boundary? • a. divergent boundary • b. convergent continental-continental boundary • c. convergent oceanic-continental boundary • d. convergent oceanic-oceanic boundary

Ch 9 Continental volcanic arcs are associated with what type of plate boundary? • a. convergent continental-continental boundary • b. convergent oceanic-continental boundary • c. transform fault boundary • d. convergent oceanic-oceanic boundary

Ch 9 If a deep ocean trench is located adjacent to a continent, active volcanoes would likely be found ____. • • a. seaward from the trench b. along the axis of the trench c. at the ends of the trench d. landward from the trench

Ch 9 Why are subduction zones not commonly found at convergent continental-continental boundaries? • a. Continental lithosphere is too buoyant to be forced down into the mantle. • b. Subduction zones are never found at convergent boundaries. • c. Oceanic lithosphere is too buoyant to be forced down into the mantle. • d. Continental lithosphere is too dense to be forced down into the mantle.

Ch 9 Strips of alternating magnetic polarities found in rocks in the ocean basins ____. • a. conflict with theory of plate tectonics • b. provide evidence that Earth’s magnetic field has never reversed polarity • c. indicate changes in Earth’s gravitation field • d. provide evidence for seafloor spreading.

Ch 9 What do the strips of low-intensity magnetism represent on the ocean floor? • a. areas where there is no magnetism • b. areas where the rocks have a normal polarity • c. areas where the rocks have a reversed polarity • d. areas of different types of rock.

Ch 9 What feature is labeled A in Figure 9 -2? • a. subduction zone • b. trench • c. volcanic island arc • d. continental volcanic arc

Ch 9 According to Figure 9 -2, if the plate labeled H descends into Earth’s interior, what will occur between the positions labeled Y and X? • a. The rock at X will be cooler than the rock at Y. • b. Earthquake foci will be shallower at Y and increase in depth at X. • c. Earthquake foci will be deeper at Y and decrease in depth at X. • d. Rifting will begin to occur between Y and X.

Ch 9 According to Figure 9 -2, if the plate labeled H descends into Earth’s interior, what will occur between the positions labeled Y and X? • a. The rock at X will be cooler than the rock at Y. • b. Earthquake foci will be shallower at Y and increase in depth at X. • c. Earthquake foci will be deeper at Y and decrease in depth at X. • d. Rifting will begin to occur between Y and X.