Midterm Study Guide – GLG115L

What is the first step in identifying rocks and minerals according to the identification tables?

Start with the first (left-most) column and move right.

What are the two classifications of igneous rock texture?

Extrusive and Intrusive.

What texture describes igneous rocks with a fine grain size due to quick cooling?

Aphanitic.

Define 'foilation' in metamorphic rocks.

The presence of layered or banded texture caused by high pressure.

What are the two main types of sedimentary rocks?

Detrital (Clastic) and Biochemical.

What are the main elements that dominate the Earth's crust?

Silicon and Oxygen.

What characterizes mafic rocks?

They contain more Fe & Mg, are darker, and denser.

Describe the process of lithification in sedimentary rock formation.

The process that compacts and cements sediments into solid rock.

What is the result of convergent plate boundaries?

Mountains, volcanoes, trenches, and subduction zones.

What is a characteristic feature of explosive eruptions?

High viscosity and the ability to trap gases.

Name an example of an index mineral in metamorphic rocks.

Micas or garnets.

What type of igneous rock texture indicates mixed cooling rates?

Porphyritic.

What process includes weathering, erosion, transportation, and deposition?

The formation of sedimentary rocks.

What describes the difference between continental crust and oceanic crust?

Continental crust is older, thicker, and less dense; oceanic crust is younger, thinner, and more dense.

What defines the term 'metamorphism'?

The process of changing a rock's form due to temperature and pressure changes.