Igneous Rocks Flashcards
What are the three main categories or families of rocks?
Igneous, Sedimentary, Metamorphic
Rocks are solid ______ of minerals
aggregates
Rocks are usually made up of…
several minerals as well as non-mineral content (organic debris, volcanic glass, etc)
What does graininess refer to?
the size of its individual mineral grains
______ is the size of a rocks individuals mineral grains
Graininess
Rock formations depend on….
environmental conditions.
Rocks contain clues to decipher geological history
How are igneous rocks formed?
from the solidification of magma
the solidification of _____ forms igneous rocks?
magma
How are sedimentary rocks formed?
by deposition of layers of sediment.
Particles of other rocks get lithified or solidified together
A _______ rock has been altered from the original rock
metamorphic
Metamorphic rocks are altered from their original rock due to these two factors…
high temperatures or high pressures
Could a metamorphic rock original have been an igneous or sedimentary rock?
Yes, due to high temp or pressures the rock was metamorphosed
The _____ cycle describes ways that rocks are transformed into different types of rocks, as well as how they melt and are broken down.
rock
Igneous rocks are formed from the _____ and _______ of magma
cooling, crystallization
What are the two main properties that dictate the type of igneous rock that forms out of the magma?
rate of cooling
the composition of the magma
Igneous rocks are categorized by their…
grain size and silica content
When magma cools very _____ then large crystals form
slowly
when magma cools very slowly the rock crystals that are forming have time to grow very large before they are fully solidified
Where does magma have time to cool slowly?
underground
We call rocks that are formed from slow cooling?
Coarse-grained
Intrusive
Plutonic
What are the three plutonic igneous rocks?
Granite, Diorite, Gabbro
Each has large mineral crystals that can be easily seen
_______ rocks form when magma is crystalized underground.
Plutonic
When magma cools down quickly then _____ crystals form
small
the mineral crystals don’t have much time to grow before they solidify.
We call rocks formed from quick cooling…
Fine-grained
Extrusive
Volcanic
Volcanic rocks have ______ grains
small
What are the three volcanic igneous rocks?
Rhyolite, Andesite, and Basalt
Where do volcanic rocks form?
at or near the surface
Do Volcanic Rocks form from the crystallization of magma or lava?
lava
Do Intrusive rocks form from the crystallization of magma or lava?
magma
What makes Pumice and Obsidian special igneous rocks?
They formed from a cooling of magma so rapid that there was no time for mineral grains to form
We can group igneous rocks based on these two factors
mineral composition and rate of cooling g
These type of igneous rocks have a high silica content
Felsic rocks
What are three properties of Felsic rocks?
- High silica content (typical minerals quartz and feldspar)
- light colored
- constitute most of the continental crust
What are two felsic rocks?
Granite and Rhyolite
If two felsic rocks are pulverized, will they have the same mineral composition/make-up?
yes
_____ and _____ are the two felsic rocks
Granite, rhyolite
These type of igneous rocks have a low silica content
Mafic
What are the four properties of mafic rocks?
- low silica content
- contain more iron rich minerals
- dark colored
- constitute most of the oceanic crust
Which igneous rock group constitutes most of the continental crust?
Felsic
This type of igneous rock contains iron rich minerals like olivine and pyroxene/..
Mafic
What are the two Mafic rocks?
Gabbro and basalt
Gabbro and basalt are the two _____ rocks?
Mafic
If I pulverized Gabbro and basalt would you be able to tell them apart?
No, because they are made of the same chemical content
This type of igneous rock constitutes most of the oceanic crust
Mafic rocks
What is the silica content of intermediate igneous rocks?
intermediate silica content
What are the two intermediate igneous rocks?
Diorite and Andesite
