Download Igneous Rocks

Today’s Objective:
What makes Igneous Rocks special?
Do Now: THINK
What are sedimentary and how are they
classified?
Environments of Formation
ESRT pg 6
Environments of Formation
– rocks that
form when magma hardens beneath
Earth’s surface.
** The slower MAGMA
cools the larger the
crystals ***
Granite
– When lava hardens on the Earth’s surface.
-Lava cools quickly, resulting in
- Smaller crystals.
- Vesicular texture (holes).
- No Crystals at all (glassy).
Textures of Igneous Rocks
Textures of Igneous Rocks
Intrusive
– Slow cooling results in the
formation of large crystals.
Extrusive
– Rapid cooling of magma or
lava results in rocks with
small, interconnected
mineral grains.
Ex: Obsidian
Extrusive
– Glassy texture results
from cooling that is so fast
that minerals do not have a
chance to crystallize.
Ex: Pumice
- Vesicles (holes, pores, or
cavities) are the result of
gas bubbles, which often
occurs during volcanic
eruptions.
Characteristics of Igneous Rocks
Composition of Igneous Rocks
– a lighter color
– a darker color
- a lower density
- a higher density
- rich in Silicon (Si) and
Aluminum (Al)
- rich in Iron (Fe) and
Magnesium (Mg)
Mineral Composition of Igneous Rocks
Rhyolite is made
up of:
- Potassium
feldspar
- Quartz
- Plagioclase
feldspar
- Biotite (mica)
- Amphibole
Mineral Composition of Igneous Rocks
What is Gabbro
made of?
- Plagioclase
feldspar
- Biotite (mica)
-Pyroxene
- Olivine
- Amphibole
Using your knowledge of earth science, your
earth science reference tables and your class
notes contrast Basalt and Granite in terms of
how each forms, the texture of each, the color
and the composition in your notebook.
Basalt
Formation
Texture
Color
Composition
Granite