GEOL 100 - EXAM 2: Textbook Questions

in progress

When a positively charged sodium ion is chemically bonded to a negatively charged chlorine ion the result is sodium chloride (i.e., the mineral halite).   This is an example of ____________________________________.

Ionic bond

Minerals have a crystalline structure. What does this mean?

Atoms are arranged in an orderly, repeating arrangement

3. What is the most common mineral formed by living organisms?

Calcite

What elements make up the silica tetrahedra, the basic unit of silicate minerals?

4 oxygens and 1 silicon

Why are mica minerals “like a sandwich”?

Because layers of weak bonds cause the platy mineral to easily cleave into sheets

Which mineral group is an important source of copper, lead, and zinc ore?

Sulfides

Which mineral property involves observing the color of a mineral in powdered form?

Streak ???

Which of the following luster descriptions is a common starting point for mineral identification?

Metallic/non-metallic

Cleavage is a result of ________________ in a mineral’s atomic structure.

weakness

If a mineral scratches a copper penny but NOT a piece of glass, then the Moh’s Hardness value for that mineral is about _________.

4.5

Porphyritic rocks with coarse grained crystals surrounded by a finer grained groundmass indicate what?

the rock cooled slowly then more quickly 

The rate of cooling for intrusive rock is

slow

Which rock composition has the least amount of silica?

Felsic

Partially melting and ultramafic rock would immediately produce magma of what composition?

Mafic

What is the name of a volcanic hazard composed of hot gases and lapill that runs downhill at tremendous speed (perhaps > 100 mph!)?

Pyroclastic flow 

What is the most common material found in sandstones?

Quartz

What do chemical and detrital sedimentary rocks have in common?

Both involve water in their formation

Which of the following is NOT part of the process of diagenesis and lithification?

Melting

Which of the following is the correct order of grain sizes from smallest to largest for clastic (detrital) sedimentary rocks?

clay, silt, sand, pebble, cobble, boulder

What story does a sedimentary rock tell?

Ideas about ancient landscapes

How can you distinguish metamorphic quartzite from sedimentary stone?

Quartzite breaks across the grains while sandstone breaks around the grain 

What are polymorphic minerals?

Minerals that have the same chemical formula but different chemical formulas 

How does burial metamorphism occur?

Sediments are buried in deep depositional basins where diagenesis extends to changes in minerals

Which of the following types of metamorphism results in a distinct foliation?

Directed stress

Index minerals are ___

Minerals that only form at certain temperatues/pressures