module 3 and 4 geology

What is an ion?

 

An atom that has gained or lost 1 or more electrons and is charged either positively or negatively.

Is glass a mineral?

 

no because it lacks a crystal structure

The most common class of minerals on Earth is:

silicates

As the silicate structures change from isolated silica tetrahedra to chains and frameworks of silica tetrahedra, the number of silicon atoms relative to oxygen atoms ________.

Increases

How do the electrons behave in a mineral with metallic bonding?

 

They can move relatively easily from atom to atom inside the mineral.

Which is the weakest type of atomic bond?

 

Van der Waals

Is concrete a rock?

true

Nonsilicate minerals make up about ____ percent of Earth’s crust.

8

Which of the following are true of light colored silicate minerals? (Select all that apply)

low density and commonin earth’s continental crust

Ion

an atom that has gained or lost 1 or more electrons and is charged either positively or negatively

Cation

an atom that has lost one or more electrons to become positively charged

anion

an atom that has gained one or more electrons to become negatively charged

What does pyroclastic texture in an igneous rock suggest about its formation?

 

The rock was likely formed by a violent volcanic eruption.

Why do we find coarse grained igneous rocks at the Earth's surface?

 

These rocks have been exposed by uplift and erosion.

What is the geothermal gradient?

 

the increases in temperature of the Earth with increased depth

Most igneous rocks are composed of ______ minerals.

silicate

What is a lahar? 

 

mudflow of volcanic ash and water

Why does a more felsic magma have a higher viscosity than a mafic magma at the same temperature?

 

felsic magmas contain more silica tetrahedrons in framework structures which resist flowing past one another

Why does water induce melting in a subduction zone?

 

The addition of water lowers the melting temperature of rock.

In igneous rocks, grain size generally indicates what about the rock?

 

how quickly or slowly the magma cooled

Which of the following could cause rock to melt? (select all that apply)

increase in temperature, change in composition, and decrease in pressure

What is partial melting?

 

some of the rock is melted, some remains solid.

Why does magma rise?  

 

magma is less dense than surrounding rock