The Rock Cycle and Igneous
Rocks
1)
Read
Harden’s discussion of igneous rocks and the rock cycle (p. 18-26, 33-35).
2)
Be
able to sketch and discuss the rock cycle diagram (Harden Fig. 2-19).
3)
What
is the origin of the term “igneous”, and what do all igneous rocks have in
common?
4)
What
are sediments, what are they composed of, and where are they deposited?
5)
What
is the difference between sediments and sedimentary rock?
6)
What
does the process of lithification involve?
7)
What
is the most distinctive feature of sedimentary rocks as a group?
8)
What
is the origin of the term “metamorphic”, and how do metamorphic rocks form?
9)
Igneous
rocks are classified based principally on what two characteristics?
10)
Why
is grain size important? Contrast grain
sizes of volcanic and plutonic rocks.
11)
Be
able to draw a simple cross-section showing a magma chamber, pluton,
sill, dike, and country rock.
12)
How
do sills and dikes differ?
13)
How
do intrusive and extrusive igneous rocks differ?
14)
All
igneous rocks share what common characteristic?
15)
What
is a batholith? Name one batholith in
California.
16)
Describe
a porphyritic texture, and what does it tell you about the cooling history of
the rock?
17)
Name
the principal igneous rock-forming silicate minerals, and group them as “light”
or “dark” minerals.
18)
Know
the igneous rock classification chart like I did in lecture, including
compositional terms such as felsic (silicic) and mafic. Know the directions that SiO2, FeO, dark
minerals, and light minerals increase or decrease according to rock type on the
chart.
19)
Peridotite
is important for at least two reasons.
What are they?
20)
What
is the most abundant type of volcanic rock on earth? Be able to make a simple cross-section sketch of oceanic crust at
a mid-ocean ridge and show where basalt and gabbro are found. What are pillow basalts and what is their
significance? (See Harden, Figs. 9-4,
12-12, and 16-28).
21)
What
is magnetite, Earth’s Magnetic Field, and the Curie point?
22)
What
is paleomagnetism and inclination?
23)
If
a lava solidifies at the equator, what will be the declination? If the lava solidifies near 45° North
latitude, what will be the inclination?
24)
Be
able to sketch the plate tectonic setting of the common rock types (granite,
rhyolite, granodiorite, andesite, diorite, basalt, and gabbro) and say a few
words about their origin.