CH 4 Intrusives

1
CH 4 - Intrusives

• Are you ready for the test?

2
What is country rock?

• Existing rock already formed.

3
What are intrusives?

• Igneous rock formed underground between country
  rock.

4
What does concordant mean?

• Parallel to country rock

5
What does discordant mean?

• Perpendicular to country rock.

6
4 ways to classify intrusives

• Size
• Shape
• Depth
• Relation to country rock

7
Most abundant intrusive rock?

• Granite

8
Why is erosion important to studying intrusives?

• Expose intrusives.

9
Shallow vs deep intrusives make what type of
rocks?

• Shallow small grained crystals aphanitic, like
  basalt
• Deep large grained crystals phaneritic, like
  granite

10
What are xenoliths?

• Alien rocks

11
Know real pictures of intrusives.
12
Name the intrusives
13
Name the intrusives
14
Know this picture
15
Use Bowens Reaction Series
Rock Textures Physical Conditions

• What minerals in what rocks?
• What minerals form in what order?
• What rocks minerals come from what magma?
• What rocks minerals are most/least stable?
• What minerals form at what temps?
• Discontinuous vs continuous branches
• Aphanitic vs Phranetic rocks

16
What rocks come from Mafic magma?

• Basalt, Gabbro

17
What rocks come from Felsic magma?

• Granite, Rhyolite

18
What rocks come from Intermediate magma?

• Andesite, diorite

19
What rocks are found at divergent boundaries?

• Mafic - Basalt, Gabbro

20
What rocks are found at convergent boundaries?

• Intermediate andesite, diorite
• Felsic granite, rhyolite

21
What three factors can lower minerals melting
points?

• Pressure
• Mixing minerals
• Pressurized Water

22
What are 4 ways magma can change?

• Differentiation crystal settling
• Magma mixing
• Assimilation
• Partial Melting

23
Be able to identify 9 igneous rocks.

• Obsidian Andesite Fine-grained Basalt
• Pumice Granite Vesicular basalt
• Gabbro Rhyolite Porphorytic Basalt