1. Earth Science Notes ROCK TYPES: Igneous Metamorphic Sedimentary

2. Igneous Rocks

3. Rocks that form from magma or lava

4. Igneous Rock Magma: molten rock below the earth’s surface  Temperature: 1202 o F to 2192 o F  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 (SiO 2 )

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 (SiO 2 )

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. 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. 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 Conglomerate Breccia

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 (CaCO 3 ) – 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