Igneous rocks Flashcards
Rock
Solid materials composed of one or more minerals
Polymineralic Rock
Rock composed of two or more minerals mixed togther
monomineralic Rock
Rock composed of a single mineral
How are rocks classified?
How they form
The Rock cycle
The continuing change from one rock type to another rock type over a very long period of time (igneous, sedimentary, metamorphic)
igneous rocks
Formed from melting and solidification of magma/lava
sedimentary rocks
Deposition, burial, compaction and cementation of sediments
metamorphic rocks
Formed from any rock type due to extreme heat and pressure
What are two ways igneous rocks can form?
Extrusive/Volcanic and Intrusive/Plutonic
Extrusive/Volcanic formation process
On earths surface, fast, the crystal is less than 1 mm or none, the texture is glassy/fine/vesicular (ex. Obsidian, basalt, pumice)
Intrusive/plutonic formation process
inside earth, slow, crystal is 1mm or greater, the texture is coarse (ex. Granite, gabbro)
Vesicular
A rock with gas pockets (holes) formed when gas bubbles became trapped in rapidly cooling lava
what are igneous rocks made of?
Depends upon the presence of certain elements (AI & SI or Fe &Mg)
If igneous rocks have Aluminum (AI) and/or Silicon (SI) they are….
Felsic, light color, low density
if igneous rocks have iron (Fe) and/or Magnesium (Mg) they are…
Mafic, dark color, high density
