Igneous rock

Chapter 4

What are the conditions that produce magma

flux melting: addition of voltiles

decompressional melting:(temp increase and PSI Decrease)

Heat transfer

Bowen’s Reaction Series?

specific order in different minerals crystallize from cooling magma

greatest to least (Olivine, pyroxene, amphibole, biottite mica)

What kind of rock forms from felsic magma cooled in a large pluton underground?

Granite batholiths

(if more then 100 km=stock, if less then 100 km=batholyth)

( from tabular intrusions) (Dike or sill)

  Distinguish between crystalline, glassy, and pyroclastic igneous rocks.

igneous intrusions and extrusions, granite diorite and basalt sloow cooling

glassy is fast cooling and did not form crytals, obsidian

volcanic explosions, pumice and tuff

Obsidian is a glassy volcanic rock.  How does it form and why is it called a “glass”?

its formed from fast volcanic cooling and is glass because it formed no crystals or mineral grains

what layer is magma from

upper mantle or asthenosphere

❑        What exactly is magma and how does magma form? 

flux, decompresional, heat transfer

what size rocks are plutonic/intrusive and volcanic/extrusive.

Clastic

ex=tiny crystals

in=big crystals

❑        What is the difference between felsic and mafic magma?

felsic high silica

mafic low silica

xenolith

foreign rock that gets trapped inside magma and becomes enclosed in an igneous rock as the magma cools.

❑        What is a pluton and how is it related to batholiths?

Pluton magma intrusion from underground while batholiths are extrusions above surface

❑        Match these igneous rocks with their textures:  obsidian, granite, tuff, gabbro, diorite.

glassy, earthy, ashy, rough and coarse

3 general texture categories for igneous rocks

glassy crystaline, a fragmential

  Know the names of the igneous rocks and their classification as intrusive or extrusive, plutonic or volcanic.  Know the volcanic equivalents of plutonic rocks

fel: rhyolite and granite

int: andesite and diorite

mafic: basalt and gabbro

ultra: Komaite and peridolite

Can you tell the difference between a plutonic and volcanic rock by looking at its texture? 

yes