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:

14. Know this picture

15. Use Bowen’s Reaction Series: 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 Rock Textures Physical Conditions

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 AndesiteFine-grained Basalt Pumice GraniteVesicular basalt Gabbro Rhyolite Porphorytic Basalt