Transcript IGNEOUS ROCKS

http://www.youtube.com/watch?
v=wv4M4wror58
ROCK
Composed of one or more minerals
Classified by
1. Origin – how they were formed
2. Mineral Content
3. Texture
ROCK
Composed of one or more minerals
Classified by
1. Origin – how they were formed
2. Mineral Content
3. Texture
IGNEOUS ROCKS
ESRT Page 6
http://www.youtube.com/watch?v=
aCnAF1Opt8M
Formation
• Solidification of magma
• Made up of inter grown mineral crystals
• Environments
a. Magma –
below ground
b. Lava –
above ground
a. Texture
Determined by the rate of cooling,
refers to the size, shape and
arrangement of crystals which
grew out of the cooling
magma/lava
1. Intrusive
• You can visibly see
Mineral crystals
the ____________
• cooled slowly,
deep beneath
the Earth’s surface
• large to medium
crystals
Pegmatite – Very Coarse Texture
Granite - Coarse Texture
2. Extrusive
• Very small or no _______________
Mineral crystals
• cooled quickly on earth’s surface
• glassy to fine (can see with a hand lens)
crystals
3. Porphyritic
• Contains crystals of two markedly different
sizes
• identify with the majority of crystals
4. Vesicular
• Porous from trapped gas pockets
b. Color
Based on the mineral content or what it is
made of
Mafic
Dark colored, high in Iron (Fe) and
Magnesium (Mg), more dense
Felsic
• Light colored, high in Aluminum (Al) and
Silicon (Si), less dense
HOW DO YOU KNOW ITS AN
IGNEOUS ROCK
1. Mineral Crystals
or
2. Vesicular – Gas pockets
Order in which minerals crystallize from a cooling
magma/lava to form igneous rocks