1)            What is the difference between island arc and continental magmatic arc?

A)        Island arcs occur in ocean-continent tectonic settings whereas continental arcs occur in ocean-ocean tectonic settings.

B)         Island arcs occur in divergent boundaries where as continental arcs occur in convergent boundaries.

C)         Island arcs and continental arcs are the same

D)       Island arcs occur in ocean-ocean tectonic settings whereas continental arcs occur in ocean-continent tectonic settings. 

2)           Which of the following is NOT and example of ocean-ocean convergence?

A)       Aleutian Islands

B)         Japan Islands

C)         Java-Sumatra/Nicobar Islands

D)       Trans-Mexican Volcanic Chain

E)         Kermadec-Tonga Islands 

3)            The San Andreas Transform is a plate boundary between which two tectonic plates?

A)       Pacific plate, Juan de Fuca plate

B)         Farallon plate, North American plate

C)         Nazca plate, Pacific plate

D)       Pacific plate, North American plate 

4)           What are the three types of plate tectonic boundaries?

A)       ocean-ocean, ocean-cont., cont.-cont.

B)         asthenosphere, lithosphere, mantle

C)         transform, divergent, convergent

D)       crust, mantle, core 

5)        What causes the mantle to melt at subduction zones (~150 km depth) to form arc volcanoes?

A)       higher temperature

B)         dewatering of ocean lithosphere

C)         mantle plumes 

6)        Igneous rocks are classified based principally on what two characteristics?

a.            volcanic, plutonic

b.              phaneritic, aphanitic

c.            texture, composition




7)        Volcanic rocks are typically ______ and plutonic rocks are typically ______.

A)       coarse grained, fine grained

B)         fine grained, coarse grained

C)         black, light

D)       mafic, felsic


8) What is the general definition of tuff?

A)        volcanic rock composed mostly of lapilli

B)          volcanic rock composed mostly of ash

C)         volcanic rock composed mostly of breccia

D)    D)    volcanic rock composed mostly of blocks

9)        Which of the following best describes tephra?

         i.          Lower flow-banded Rhyolite at Pinnacles

       ii.           Perlite in Lower Rhyolite unit

      iii.          Pink, Rhyolite Breccia unit

     iv.          Green Lapillit Tuff unit



10)    Stratovolcanoes have _____ lava and ______ eruptions.

A)        andesite, explosive

B)          mafic, non-explosive

C)          felsic, explosive

D)        basaltic, explosive


11)     What is the approximate age of the Pinnacles and Neenach volcanic fields, what is their geographic relationship, and what evidence do they provide concerning movement along the San Andreas fault?






12)     Why is the distinction between the San Andreas Transform and San Andreas Fault important?






13)     Which unit found at the Pinnacles and at the Neenach volcanic fields is characterized by glassy, perlite at top of the lava flow?







14)    Which volcanic unit exposed at the Pinnacles is not exposed at the Neenach volcanic field?







15)  How are the “caves” found at Pinnacles formed?







16)  If the rate of movement on the San Andreas Fault System is 2 cm/yr, how long in millions of years will it take for the Pinnacles to reach the Bay Area that is 100 miles to the north?






17)  What is a triple junction?







18)  What has been the geologic history of the Mendocino Triple Junction since its birth 28 million years ago?







19)  What is a slab window and how does this contribute to magmatism?







20)  Subduction zone magmatism occurs near the trench (like the Pinnalces and other volcanics in the Coast Ranges). TRUE or FALSE







21)  What is the age of eastern Coast Range Volcanics as you move from south to north (what is the age progression)?