Geology 1010 Chapter 4 Exam Questions
with Correct Answers
What does course grained igneous stone mean? - Answer- You can see all the stones
that make it up in there like the top of a rocky mountain brownie
What is a fine grain igneous stone? - Answer- The minerals are too small to individually
identify
What is porphyritic texture? - Answer- Igneous texture- small and large crystals in one
rock- two stages of cooling
What causes course grained stones? - Answer- Slow cooling time allowing for separate
minerals to grow.
What is the difference between intrusive and extrusive stone? - Answer- Intrusive was
created inside and extrusive was created outside.
What is pumice? - Answer- a very light and porous volcanic rock formed when a gas-
rich froth of glassy lava solidifies rapidly.
What is scoria? - Answer- It is a larger version of pumice
What is obsidian? - Answer- a sharp, glasslike volcanic rock, very felisc and it can have
small crystals in it
Which one of the following magma compositions has the highest viscosity? - Answer-
Felsic
What is the order of magma viscosity from lowest to highest? - Answer- Ultra Mafic
Mafic
Intermediate
Felsic
What happens when you melt an ultra mafic rock? - Answer- It moves up a step and
becomes mafic.
What happens when you melt a rock? - Answer- It moves up a step in viscosity.
with Correct Answers
What does course grained igneous stone mean? - Answer- You can see all the stones
that make it up in there like the top of a rocky mountain brownie
What is a fine grain igneous stone? - Answer- The minerals are too small to individually
identify
What is porphyritic texture? - Answer- Igneous texture- small and large crystals in one
rock- two stages of cooling
What causes course grained stones? - Answer- Slow cooling time allowing for separate
minerals to grow.
What is the difference between intrusive and extrusive stone? - Answer- Intrusive was
created inside and extrusive was created outside.
What is pumice? - Answer- a very light and porous volcanic rock formed when a gas-
rich froth of glassy lava solidifies rapidly.
What is scoria? - Answer- It is a larger version of pumice
What is obsidian? - Answer- a sharp, glasslike volcanic rock, very felisc and it can have
small crystals in it
Which one of the following magma compositions has the highest viscosity? - Answer-
Felsic
What is the order of magma viscosity from lowest to highest? - Answer- Ultra Mafic
Mafic
Intermediate
Felsic
What happens when you melt an ultra mafic rock? - Answer- It moves up a step and
becomes mafic.
What happens when you melt a rock? - Answer- It moves up a step in viscosity.
