Exam 2 part 1 Flashcards
Study for exam 2.
What are Felsic and Mafic rocks and what do the terms mean?
Igneous Rocks, Felsic and Mafic are terms to describe what they are made of
What does felsic and mafic mean in terms of composition?
It means that felsic rocks have more silica in them while mafic rocks do not.
What influences Magma behavior?
Silica content
Generally, what silica content does Granitic Magma have and what consistency does it have?
It generally has a high silica content and it’s consistency is also viscous, meaning it has high resistance to internal flow
Generally, what silica content does Basaltic Magma have and what consistency does it have?
It generally has a low silica content and it’s consistency isn’t viscous, meaning it has low resistance to internal flow
What does intermediate mean for felsic and mafic rocks?
It means that it’s in the middle between felsic and mafic rocks in terms of it’s silica content.
What kind of rock is Phaneritic and where can you find it?
It’s a coarse grained igneous rock and you can find it from cooled magma underground
What kind of rock is Aphantitic and where can you find it?
It’s a fine grained igneous rock and you can find it from cooled magma above around.
What is the name of a Felsic Phaneritic rock?
Granite
What is the name of a Felsic Aphanitic
Rhyolite
What are Obsidian and Pumice and what is the difference between them?
They are both igneous rocks with glassy texture, but obsidian is compact and dark in color while Pumice is frothy and light in color
What are Andesite and Diorite and what is the difference between them?
They are both igneous rocks but Andesite has a volcanic origin and is fine grained and Diorite has a Plutonic origin and is coarse grained
What is Basalt and what is it made of?
Volcanic igneous rock with a amphanic texture. Made of calcium-rich plagioclase feldspar and pyroxene.
What is the most common extrusive igneous rock?
Basalt
What is Gabbo and what is an equivalent of?
Plutonic igneous rock with a Phanetitic texture. Equivelant of Basalt meaning it’s also made of calcium rich plagioclase feldspar and pyroxene
Which rock is a significant percent of the ocean floor?
Gabbo
What are pyroclastic rocks?
Fragments ejected during a volcanic eruption
What is tuff?
Ash-sized fragments
What is Volcanic Breccia?
Fragments bigger than ash
What is tuff made of?
It can be made of anything that’s in the lava flow. Tuff is just a fragment size
How does heat work in the crust?
It gets warmer, 20 celcius to 30 celcius per kilometer
If rocks are near their melting point, where are they usually?
In the lower crust and upper mantle
When you have a lot of pressure on a rock what does it do?
It increases the rock’s melting point in temperature
What happens if you decrease the pressure of a rock that has had a lot of pressure on it?
It will melt because of decompression melting
