Earth Science Notes

1. Earth Science Notes ROCK TYPES: Igneous Metamorphic Sedimentary

2. Igneous Rocks

3. Igneous Rocks • Rocks that form from magma or lava

4. Igneous Rock Magma: molten rock below the earth’s surface • Temperature: 1202oF to 2192oF • Located about 90 miles below the surface of the earth. • Magma is less dense than the surrounding solid rock, so it is forced to the surface.

5. Igneous Rock Lava: molten rock on the surface of the earth • Density of lava effects how fluid it is. • Dense lava flows very slow and has a different chemical composition than fast moving, less dense lava.

6. Types of Igneous Rocks Intrusive rocks: rocks made from magma • When magma cools the molecules and atoms in the magma begin to crystallize. • These rocks cannot be seen until the rock that is around it is worn away. • Sometimes earthquakes will expose intrusive rocks.

7. Intrusive Rocks

8. Types of Igneous Rocks Extrusive Rocks – rocks formed from lava. • Created when lava cools and hardens on the surface • Because of exposure to the air and other elements (i.e. water) lava will cool quickly keeping crystals small. • Volcanic glass forms this way.

9. Extrusive Rocks Tuff: formed from volcanic ash, pumice and scoria

11. Classifications of Igneous Rock • Basaltic Rocks • High Density, Dark Colored, Very Fluid • Chemical Composition: Iron, Magnesium, low silica (SiO2)

12. Basalt Rock Formations

13. Classifications of Igneous Rock • Granitic Rocks • Light Colored, Low Density, Very rigid • Chemical Composition: low magnesium and Iron, high silica (SiO2)

14. Granitic Rock Formations

15. Classifications of Igneous Rock • Andesitic Rocks • Intermediate between Basaltic and Granitic

18. IGNEOUS ROCKS Summary • Where do Igneous Rocks come from? • Magma and Lava • Types of Igneous Rocks • Intrusive / Extrusive • Classification of Igneous Rocks • Basaltic / Granitic / Andesitic

19. Metamorphic Rocks

20. Metamorphic Rocks • Rocks that are created because of a change in pressure and temperature.

21. Metamorphic Rock Formation • Metamorphic rocks can form igneous, sedimentary, or other metamorphic rocks. • Pressure on these rocks can be due to the immense amount of force applied from the rock above it. • Temperature can come from a rock being in close proximately of magma.

22. Classification of Metamorphic Rock Rocks are classified according to composition and texture. • Foliated rocks – formed when mineral grains line up in parallel layers. • Ex: Slate – used for blackboards, roofs, sidewalks

23. Foliated rocks

24. Classification of Metamorphic Rock Rocks are classified according to composition and texture. • Nonfoliated rocks – metamorphic rocks where mineral grains (crystals) grow and rearrange, but they do not form layers. • Ex: Quartzite – formed from sandstone that was changed by immense heat and pressure. Quartz crystals grow in size and become interlocking. • Ex: Marble – marble forms when limestone is put under extreme pressure and temperature.

25. Nonfoliated rocks

26. Metamorphic Rocks Summary • Metamorphic Rock Formation • Heat and pressure • Any rock type can become metamorphic • Classification • Foliated / Nonfoliated

27. Sedimentary Rocks

28. Sedimentary Rocks • Rocks formed from sediments • Sedimentary rocks often form as layers on the bottom of a body of water.

29. Sedimentary Rock Formation • Sediments are loose materials like small rocks, minerals, and organic debris. • Weathering and erosion produce sediments • Weathering – the breaking down of rocks into bits via chemical and mechanical means. • Erosion – the moving of these small bits of rock to a new location where they are deposited.

30. Sedimentary Rock Formation • Weathering and Erosion

31. Sedimentary Rock Formation • Sedimentary rocks form from other rocks • These rocks are compacted and cemented together. • Compaction – sediments stick together due to pressure • Cementation – minerals are deposited between pieces of sediment – holding it together.

32. Sedimentary Rock Formation • Compaction and Cementation

33. Classification of Sedimentary Rocks Detrital Sedimentary Rocks: sedimentary rocks made from broken bits of other rocks • Ex: Conglomerate – large sediments, rounded rocks • These types of rocks have rounded sediments because they were near wind and water • EX: Breccia – large sediments, sediments have sharp angles • These types of rocks have jagged sediments because they were not near wind and water

34. Detrital Sedimentary Rocks Breccia Conglomerate

35. Classification of Sedimentary Rocks Chemical Sedimentary Rocks: sedimentary rocks that form when dissolved minerals come out of solution. • Often founds along seas or lakeshores. • This type of rock is the only form of sedimentary rock that did not form from preexisting rocks. • Ex: Limestone (CaCO3) – forms when calcium carbonate comes out of a solution. • Limestone is deposited on bottom of lakes and seas. • Ex: Rock salt – forms when the evaporation of water occurs, leaving behind the salt

36. Chemical Sedimentary Rocks

37. Classification of Sedimentary Rocks Organic Sedimentary Rocks: sedimentary rocks made of once living things • This type of rock will form when clams, corals, snails, and mussels die and let their shells accumulate on the ocean floor. • Ex: Chalk – made from the shells of organisms. • Ex: Coal – formed from the decay and compaction of plant materials.

38. Organic Sedimentary Rocks

39. Sedimentary Rocks Summary • What makes a rock Sedimentary? • Formation of Sedimentary Rocks • Classification of Sedimentary Rocks • Detrital / Chemical / Organics