1. Part 3: Igneous Activities - Intrusive & Extrusive
IGNEOUS ROCKS
Part 3: Igneous Activities - Intrusive & Extrusive

2. ROCK CYCLE Emphasizing Igneous Rocks

3. MODEL OF IGNEOUS ROCK BODIES
cinder cone
lava flow
composite volcano
Volcanic neck
volcanic pipe
sill
dike
magma
stock
batholith
laccolith

4. INTRUSIVES
Dikes (small, discordant intrusives)

5. INTRUSIVES
Xenoliths & assimilation

6. Magmatic differentiation
Crystal settling can concentrate mafic minerals
Remaining magma is more felsic

7. VOLCANOES Types: Shield (Hawaiian) Composite (Mt. St. Helens)
Cinder cone (Sunset Crater, Arizona)

8. VOLCANIC ERUPTIONS
Doming, outgassing, & earthquakes before eruption

9. VOLCANOES Western North American volcanoes
Plate tectonic collision zone (subduction)
Andesitic composition
Explosive
Part of the Pacific Ocean Basin's marginal "ring of fire"
Can you locate Mt. St. Helens?

10. HAWAIIAN ("hot spot") BASALTIC NON-EXPLOSIVE FLOWS

11. LAVA FLOW TYPES Aa (blocky) in Hawaii Pahoehoe (ropey) in Hawaii
less fluid
cooler
thick crust
fractured surface
Pahoehoe (ropey) in Hawaii
more fluid
hotter
thin crust
surface not brittle

12. LAVA FLOW TYPES Pillow lavas Eruptions of Basalt under water
Mid-ocean ridges (=plate tectonic spreading zones)

13. END OF FILE

15. BASALT

17. GRANITE