Igneous rocks & Volcanoes study Flashcards
Why rocks?
Most Earth processes involve rocks
what is a rock?
A solid mass of minerals or mineral type materials
do rocks have multiple minerals
Yes, some have multiple minerals, but others have just one, and some have no minerals, or organic materials
How many types of rocks are there
5
Igneous
Formed from cooled lava or magma (melted rock)
All rocks start here
what do all rocks start as
a igneous rock
What type of rocks are igneous
Lava, and magma
Sediments
When rocks are exposed to weathering forces it creates sediments
What happens when sediments are compacted
It creates sedimentary rocks (Lithification)
Metamorphic
When rocks are exposed to heat and pressure it changes the chemistry of the rock
The heat is not enough to melt, it is around 150-200 °C
what are Igneous rocks formed from?
Formed from rocks that have melted then cooled
Intrusive Rock
Forms from magma that has cooled below the surface
It is formed inside the earth*
Extrusive Rock
Forms from lava that cools at the surface
It is formed at the surface of the earth
Phaneritic
Coarse grained, large easy to see crystals or grains
Ex. granite
Aphanitic
Fined grained, smaller crystals or grains that cooled quickly
Ex. Basalt
Porphyritic
Has both large and small crystals because it cools at different times
Ex. Andesite porphyry
Glassy
No crystals because it cools so fast
Ex. Obsidian, and pumice
It is smooth
Felsic
Contains a lot of feldspar and silica, Usually light in color and less dense
Ex: Granite
Mafic
Contains large amount of magnesium and ferrum (iron) rich silicates, Usually dark in color and more dense
Ex: Basalt
What are the most common igneous rocks
Granite (In), and basalt (Ex)
Volcano
as rock melts it becomes less dense and rises. If the molten rock can escape through a crack or think spot it creates a volcano
Magma
molten rock that is below Earth’s surface
Lava
molten rock that is on Earth’s surface
Something that comes out of a volcanoe
Divergent Boundary
where plates are pulled apart
Convergent Boundary
where plates are pushed together
Hot Spots
Intraplate volcanoes are not at a plate boundary at all but in the middle of a plate
What is a Volcano?
A mountain that spews out things like lava, magma, ash, etc.
Everything is around 1,000 - 2,000 °F
Active volcanoes
A volcano tha is erupting or showing signs of erupting
Dormant volcanoes
not active but could reawaken
Extinct volcanoes
extremely unlikely to awaken
Very unlikely to erupt
Can volcanic explosions be explosive
Yes, the can be both explosive, and gentle
Felsic (granite)
gives very thick or viscous magma so you are more likely to see explosive eruptions, due to trapped gas
Mafic (basalt)
Is thinner so gas can easily escape so usually less explosive eruptions
Is lava the only thing that comes out of a volcanoes
No
exspect lava what do volcanoes spew out
gases like water vapor, carbon dioxide, sulfur, etc.
Can Pyroclastic also come out of a volcanoes
yes
Pyroclastic clouds
the combo of super heated gas and dust
Shield volcanoe
usually form from basaltic lava, they are large broad and flat. Usually less explosive.
Ex: Hawaii
Cinder Cone volcano
are formed from dust, ash, and cinders
Composite volcano
Are symmetrical. They have layers of lava and pyroclastic material
Crater
A big hole, usually from a expslosion
Caldera
formed when a volcano is no longer active and the top of the magma chamber starts to collapse in on itself
Volcanic Necks
when magma hardens within a vent on a active volcano
Lava Plateaus
Extensive areas of flood basalt
Often at fissures where there is flood lava
Plutons
Structures formed from magma cooled underground
Sills
Cooled magma between parallel layers of sedimentary rock
Laccolith
Similar to sills but in a lens shape because of thicker magma
Dikes
Magma moves into a break in the rock layers
Hot springs
groundwater is heated by magma and forced to surface
Mudflow
volcano melts ice and combines with debris
Geyser
if heated groundwater turned to steam
Geothermal
heat can be harvested for energy
what is another name for a Igneous rock?
they are also called volcanic rocks
Where are Igneous rocks formed?
Some igneous rock forms at the surface but most is underground
Do extrusive rocks have crystals
yes, and no, they tend to have smaller or no crystals because of fast cooling.
Do intrusive rocks have crystals?
yes, and they tend to have larger crystals because of slow cooling.
What is another name for a intrusive rock?
they are sometimes called plutonic rock
