Please fill out and return this sheet after viewing Program #6.   If you are unsure of an answer, give your best intelligent guess.
 

1.  What intellectual dispute did James Hutton have with Abraham Werner?

Hutton believed that granites formed from cooling magma; Werner believed that granites crystallized from oceans (his approach was "Neptunism")

2.  What are sources of heat in Earth's interior?

Residual heat from Earth's formation; radioactive decay of certain unstable elements

3.  What are different compositional categories of igneous rocks?

mafic magmas contain more iron, magnesium, and calcium; felsic rocks contain more aluminum, sodium, potassium

4.  How do glassy igneous textures form?

from instantaneous cooling (quenching) that happens so quickly that crystals don't have time to form.

5.  What is the general difference in crystal texture between plutonic and volcanic rocks?

Plutonic rocks have coarser (larger) grains; volcanic rocks have finer (smaller) grains

6.  What minerals crystallize first in the discontinuous series of Bowen's Reaction Series?

olivine and pyroxene

7.  What composition of plagioclase feldspar crystallizes first in the continuous series of Bowen's Reaction Series?

calcium-rich

(can you explain what Bowen's Reaction Series is?)
 

8.  How does the H2O content affect the temperature at which rocks can melt?

additional H2O lowers the temperature at which a rock melts

9.  What is the difference between the types of magma's derived from mid-ocean ridges and from subduction zones?

mid-ocean ridges produce more mafic (basaltic) magmas; subduction zones produce magmas that are a little more felsic (andesitic)

10.  What are plutons?

intrusions of magma that accumulate undergroud.  Often they form magma chambers to supply volcanic lava.

11.  What are dikes?  sills?

vertical planar intrusions that typically cut across layering; sills are horizontal planar intrusions that generally are parallel to sedimentary layers.

12.  What are batholiths?  How do they form?  What is a specific example of a batholith?

large intrusions that form when successive plutons rise toward the surface and crystallize.  Sierra Nevada batholith

13.  What is the compositional difference between continental and oceanic crust?

continental crust is generally more felsic; oceanic crust is more mafic