Transcript Igneous Rocks

Aim: How are Igneous Rocks formed?
Do Now: Take out your ESRT and turn to page 6. Look
at the chart called Scheme for Igneous Rock
identification and answer the questions below.
1) What types textures of igneous rocks will we see?
2) List the two environments of formation for Igneous
Rocks?
- what do you think “in” and “ex” refers to in each word?
I. Igneous Rock:
• Igneous means “fire”
• These rocks come from very hot material
such as magma or lava.
- Magma is found below the crust (inside
the Earth)
- Lava is found on top of the crust
(Outside the Earth)
II. Environment of Formation
A. Intrusive (plutonic) – when magma
cools/hardens beneath Earth’s surface.
(intrusive = inside)
•Magma cools slowly
underground.
•Creates a coarse
texture. (large
crystals)
Granite
B. Extrusive (volcanic) - when lava
cools/hardens above the Earth’s surface.
• Lava cools quickly
on the surface.
•Creates fine, glassy
and vesicular
textures.
Rhyolite
III. Textures
- Coarse (large) crystals
- Fine (small) crystals
- Glassy (no crystals)
- Vesicular (gas pockets)
Granite
Pumice
Obsidian
Rhyolite
With your partner, take 3 min to walk around
the room and find the 4 cards labeled Rock A,
B, C and D.
Identify the Texture of each group of rocks at
the card using your notes we just took.
IV. Other Characteristics
• Color is described as light or dark
• Density is described as high or low
• Composition is described as:
- Mafic: containing Iron (Fe) and Magnesium (Mg)
- Felsic: containing Silicon (Si) and Aluminum (Al)