GL 107 Earth Systems Science
K. Hannula
Discussion questions for 9/24/07
1. Which metamorphic changes tend to be the result of increases in temperature?
Mostly changes in minerals in the rock, especially changes from clay minerals to micas.
2. Which metamorphic changes tend to be the result of increases in pressure?
- Changes in minerals, to minerals in which atoms are packed more closely. Also, directed pressure, or "stress", causes minerals to change in orientation or to fold.
3. Define "foliated texture."
A layered or banded appearance to a metamorphic rock, caused by parallel alignment of minerals.
4. Describe the typical features of the following metamorphic rocks:
slate: fine-grained metamorphic rock with a foliation (or rock cleavage) which allows the rock to be broken into sheets
schist: foliated metamorphic rocks in which the mineral grains are visible.
gneiss: banded metamorphic rock that usually doesn't contain many platy minerals. Usually has alternating light- and dark-colored layers.
marble: Metamorphic rock consisting of large interlocking calcite grains.
quartzite: metamorphic rock consisting of grains of the mineral quartz.