1. Aim: How are igneous rocks formed? Do Now: Describe what “Solidification” means in your own words.

2. How does the lava change as it moved across the landscape? Why?

3. How can we describe how Igneous rocks form? Intrusive vs. Extrusive Rocks Lava – forms Extrusive rocks Magma – forms Intrusive rocks

4. How would we describe intrusive igneous rocks? Intrusive (Plutonic) rocks Rocks form underground from slow cooling of magma Large visible interlocking and intergrown mineral crystals.

5. Extrusive (Volcanic) rock Rocks form on the surface from fast cooling lava Very small or non-visible mineral crystals How are extrusive igneous rocks different from intrusive igneous rocks? Some volcanic igneous rocks can form from ash and dust

6. How are the following two igneous rocks different? Depending on the minerals in the magma/lava, it will groups igneous rocks according to their mineral composition and color. Felsic Rocks Mafic Rocks

7. Why are igneous rocks felsic in color? Felsic- Light-colored; silica rich magma/lava (very viscous and thick), contains large amounts of potassium feldspar, quartz, and aluminum (Al). **Felsic rocks have a low density. (less dense). Felsic rocks minerals: Potassium Feldspar (pink) Quartz (white/clear) Biotite (black) Amphibole (Hornblend) Ex. Granite is an example of a felsic igneous rock

8. Why are igneous rocks mafic in color? Mafic- Dark-colored, magma/ lava is low in silica (thinner), contains higher amounts of iron (Fe) and magnesium (Mg). **Mafic rocks have a high density (more dense). Mafic rock minerals include: – Plagioclase Feldspar (Ca) – Pyroxene – Olivine – Amphibole Ex. Basalt is an example of a mafic rock.

9. ESRT page 6

10. Summary Igneous Activity Identify if the igneous rock samples are intrusive or extrusive and explain why. Rock Samples Intrusive or Extrusive Reason Bonus Question Mafic or Felsic Intrusive Very slow cooling -very large crystals Felsic Extrusive Fast Cooling – small crystals Mafic Intrusive Slow cooling - large crystals Felsic

11. Extra Summary Questions 1.How do we differentiate between intrusive and extrusive igneous rocks? 2.Why are their mafic and felsic color igneous rocks? 3.Why does pumice float in water? 4.How can igneous rocks be classified?

12. Summary Igneous Activity Identify if the igneous rock samples are intrusive or extrusive and explain why. Rock SamplesIntrusive or Extrusive ReasonBonus Question Mafic or Felsic