Author Question: The classification of rocks into igneous, metamorphic, and sedimentary rocks is a genetic ... (Read 173 times)

audragclark · **on:** Jul 16, 2018

The classification of rocks into igneous, metamorphic, and sedimentary rocks is a genetic classification. Create a descriptive classification of rocks.

Compare that classification system to the genetic one. Assess the strengths and weaknesses of each system.
What will be an ideal response?

Question 2

Which conditions are required for metamorphism?

What will be an ideal response?

milbourne11 · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

The students will invent some sort of descriptive classification. We suspect classifications based on color and grain size will be common. Other things such as shape or size of the actual rocks may also be suggested.
We suspect that many students will state that two advantages of the descriptive system are: 1) it is descriptive; and 2) it is easy to use. A disadvantage of the descriptive system would be the lumping together of rocks that have formed in numerous ways. The current system base on origin is more difficult for a beginning user because it requires interpretation but it is more useful in understanding how the Earth works.

Answer to Question 2

High temperatures and pressures, similar to those found within Earth.