Oceanography 10                                                                                                 West Valley College

R. Lopez                                                                                                                

Study Questions Chapter 3 (page 53-85:

Plate Tectonics, Sea Floor Spreading, and the Scientific Method


1)       The Earth is composed of three compositional layers.  Name all three (p. 54 Fig. 3.1 text).



2)       The CRUST is the outer skin of the earth and it is composed of two types.  What are they? 




3)       Define earthquake focus, epicenter, body waves, and seismic waves.




4)       What is the difference between p-waves and s-waves?




5)       How do we know that Earth’s outer core is liquid FeO metal and that the inner core is solid FeO metal?




6)       The CRUST and the uppermost MANTLE make up the outer rocky layer of the Earth.  What is this sphere called? (Hint: it means rock in Greek; p. 58, text)



7)       Below the rocky sphere of the Earth is the aesthenosphere.  What is the definition of the aesthenosphere? (p. 58 of text)




8)        The boundary between the crust and upper mantle is known as the ___________?




9)       How do theories in science differ from non-scientific theories like the ones that you may read about in newspapers?





10)    Fill in the blanks: In the Scientific Method, you 1) Raise questions; 2) Gather data; 3)___________; 4) Prediction; 5) _________________.



11)    Name the three basic concepts of Plate Tectonics.



12)    There are three types of Plate Tectonic boundaries: Transform, ___________, and ____________.




13)    Mid-Oceanic Ridges are examples of what type of Plate Boundary?



14)    Mid-Oceanic Ridges are really chains of huge undersea _______________?




15)    The process of generating new oceanic crust is called Sea Floor Spreading.  Where does this occur?



16)     A region of magnetic force encompasses the Earth.  The lines of force leave near the geographic South Pole and reenter the Earth near the geographic North Pole.  This is known as Earth’s _____.




17)    When basaltic lava forms at a Mid-Oceanic Ridge, minerals called magnetite act as tiny compass needles that point to the magnetic North Pole.  If the magnetite minerals are aligned horizontal in the rock, then you are at (a) North Pole or (b) Equator?





18)    What are Magnetic Reversals?





19)    Describe Normal Polarity vs. Reverse Polarity by drawing lines of force either leaving or entering the North and South Poles.





20)    What is Paleomagnetism (see page 75, Garrison)?





21)    What instrument do we use to measure the direction and amount of residual magnetism in a rock (top of page 76, Garrison)?




22)    Magnetic anomalies are the alternating patterns of reverse and normal magnetized stripes on the sea floor that are symmetric about a spreading center.  Be able to briefly describe how they originated by using the concepts of Sea Floor Spreading and Plate Tectonics (see p. 76-77, Fig. 3.28, Garrison text).






23)    What are the three types of Convergent Boundaries?




24)    Continental Volcanic Arcs form at Ocean-Ocean convergent boundaries. True or False?





25)    Be able to describe how Island Arcs form (i.e. convergent margin subduction zone, upper mantle melting, magma rising into crust, formation of island arc volcanoes; p. 51 and Figs. 3.17 Garrison).





26)    Know the difference between a Fracture Zones and Tectonic Transform Boundary (p. 74, Fig. 3.25).






27)    What is the difference between Island Arc Volcanoes and Ocean Island Volcanoes?




28)    The Hawaiian Islands consist of a chain of volcanic islands that form a line of islands and seamounts together with the Emperor Seamount Chain in the northern Pacific Ocean.  How do these chains of volcanic islands and seamounts support the Theory of Plate Tectonics? (Fig. 3.33)