Rocks and Minerals

1. Rocks and Minerals Science 2201

2. Grains of sand…

3. Many ongoing processes constantly change the surface of the globe.

4. Our Earth is cyclic and restless.In other words, ---everything on the earth operates in cycles---the surface of the earth is constantly changing

5. Geology • The science that considers the history of the earth, as recorded in rocks

6. Basic Structure of the Earth • 8,000 miles in diameter • lithosphere, hydrosphere, atmosphere • 4 spherical regions: • crust, mantle, outer core, inner core

7. Earth Structure

9. Rocks • Igneous = formed by the cooling and crystallization of magma (melted rock) • Sedimentary = formed from accumulation of weathered material (sediments) • Metamorphic = formed from preexisting rocks that have been transformed (changed)

10. Igneous, Sedimentary, Metamorphic ü    Each type of rock records a different complex past. ü    Each type of rock can be changed from one form to another and back again.  geologists call these transformations the “rock cycle”

11. Rock Cycle

12. Rocks An aggregate or mixture of minerals. Composition can vary Most rocks are composed of more than one mineral Minerals Inorganic chemical elements or compounds found in the Earth’s crust. > 3000 minerals are found in Earth’s crust What are Rocks? What are Minerals?

13. Limestone made of Calcite

14. Granite contains 3 minerals.

15. Minerals ·  minerals are the building blocks of rocks ·  differ in composition and properties See Minerals link on Pacing Guide • Weinman Mineral Museum…you gotta go!

16. Pyrite, Fe2S Quartz, SiO2 Crystal Form

17. 1.Talc 2.Gypsum 3.Clacite 4.Fluorite 5.Apatite 6.Orthoclase 7.Quartz 8.Topaz 9.Corundum 10.Diamond Moh’s Hardness Scale

18. Cleavage & Fracture

19. Crystal form Hardness Plane of Cleavage Luster Color and Streak Specific Gravity Physical Properties of Minerals

20. Mineral Luster • the appearance of its surface as it reflects light • minerals of the same color can have different luster.

21. Color and Streak • Color: red rubies, or blue sapphires, same mineral—corundum (Al2O3) • Streak refers to the color of a mineral in its powdered form, example – hematite

22. Specific Gravity • A density measure • compares weight of a volume of substance to the weight of the same volume of water • Example: • cm3 pyrite weighs 5X as much as cm3 water • cm3 gold weighs 20X more than cm3 water

23. Igneous Rock ·  formed by cooling & crystallization of magma. ·   means “formed by fire” ·  make up about 95% of the earth’s crust · basalt (ocean floor) and granite (continents) are common examples

24. Extrusive Form at earth surface Example-basalt Fine texture Small minerals Fast cooling Intrusive Form inside crust Example-granite Course texture Large minerals Slow cooling Igneous Rock

25. Igneous Rocks

26. Sedimentary Rock ·  formed from the weathered material carried by water, wind, or ice ·  most common rocks in the upper crust ·  cover over 2/3 of the earth’s surface ·  sandstone, shale, and limestone

27. Clastic Broken pieces of rock Particle deposition at river bottom, beach, or desert Cementation Ex-quartz mineral forms sandstone Chemical Dissolved materials precipitate from solution Inorganic or organic Ex-calcite mineral or calcium carbonate from shells forms limestone Sedimentary Rock

28. Sedimentary Rocks

29. Metamorphic Rock • ---formed from preexisting rocks (igneous, sedimentary, or other metamorphic) • ----metamorphic means “changing in form” • ----marble and slate are common examples

30. Foliated Elongated minerals align in parallel layers H & P separates minerals into parallel layers Igneous granite to metamorphic gneiss Nonfoliated Smooth, solid homogenous blend of minerals in rock H & P recrystallizes rock Igneous limestone to metamorphic marble. Metamorphic Rock

31. Metamorphic Rock

32. Metamorphic Rock Origin • Slate from shale • Quartzite from sandstone • Marble from limestone

33. Discussion Question for Review • Chapter 17 Try p. 362-363 Discussion Questions 1-5, 7,9,10. • Chapter 18 Try p. 387 Discussion Questions 1,2,3,5.