1. Earth Science Standard 3c: Students know how to explain the properties of rocks based on the physical and chemical conditions in which they formed, including plate tectonic processes.

2. As magma cools and crystallizes minerals form in predictable patterns Bowen discovered 2 main patterns: a)Right-branch – continuous, gradual change of mineral compositions in the feldspar group b)Left-branch – minerals rich in iron and magnesium change abruptly as the temperature of the magma decreases

4. 1.Texture (Rate of Cooling) 2.Color (Mineral Composition)

5. Determined by rate of cooling where and how fast the lava or magma cooled 2 Locations of cooling: a)Intrusive (cooled inside Earth) b)Extrusive (cooled on Earth’s surface)

6. Not exposed to weather since inside Earth Very hot within Earth so cooling takes a long time! Slow Cooling Large mineral grains (can see with human eye) Hundreds to millions of years to cool The larger the mineral grains the slower it cooled! Coarse-grained Texture (phaneritic)

8. Intrusive: Course-grained, interlocking

9. Exposed to weather since form on top of Earth Cooler on Earth’s surface so cools more quickly! Very Fast Cooling = NO mineral grains & Glassy Texture Hours to Days Fast Cooling = Fine-grained Texture (mineral grains not seen with human eye (aphanitic) Days to Weeks

11. Porphyritic = started cooling slowly and the cooling sped up Some large crystals (phenocrysts)surrounded by a fine-grained texture

13. Intrusive: Course-grained, interlocking Extrusive: Fine-grained, discrete crystals, often glassy

14. Determined by mineral composition 4 classifications: a)Felsic b)Mafic c)Intermediate d)Ultramafic

15. a)Felsic = Light colored; white to pink; high silica b)Mafic = Dark colored; blackish-gray; low silica c)Intermediate = Gray; between felsic and mafic d)Ultramafic = black-green; very low silica

16. Felsic = continental crust Mafic = oceanic crust Intermediate = coastlines

18. Extrusive FelsicIntermediateMaficUltramaficTexture ObsidianBasaltic Glass Glassy (non- crystalline) RhyoliteAndsesiteBasaltFine- grained Intrusive GraniteDioriteGabbroPeridotiteDuniteCoarse- grained Pegmatite Very Coarse- grained Classification of Igneous Rocks

19. Formation of Igneous Rocks Pyroclasts Extrusive Intrusive Porphyry: partially crystalline

20. Compositional Classification Granite Quartz Orthoclase Biotite Plagioclase

21. Compositional Classification Granite Granodiorite Quartz Amphibole Plagioclase

22. Compositional Classification Granite Granodiorite Diorite Plagioclase Amphibole

23. Compositional Classification Granite Granodiorite Diorite Gabbro Plagioclase Pyroxene

24. Compositional Classification Granite Granodiorite Diorite Gabbro Peridotite Pyroxene Olivine

26. Granite Gabbro Intrusive Igneous Rocks

27. Rhyolite Basalt Extrusive Igneous Rocks Where did these rocks form? How can you tell? Color?