1. Earth Science Rocks

2. What is a Rock?

3. A group of minerals bound together!

5. Classification of Rocks

6. Igneous Rock Formed by the cooling and hardening of magma.

7. Sedimentary Rock Formed by layers of sediments.

8. Metamorphic Rock Formed by heat and pressure on other rocks.

9. Rock Formation Review

13. Igneous Rocks Make up 95% of the rocks of the crust of Earth.

14. Classifications

15. Intrusive Igneous Rock Forms below the Earth’s surface.

16. Forms when magma enters a pocket or chamber underground and solidifies into crystals as it cools very slowly.

17. Slow cooling allows large crystals to form.

18. Mineral crystals within intrusive igneous rocks are large enough to see without any magnification.

19. Granite

20. Extrusive Igneous Rock Forms above the Earth’s surface.

21. The lava cools very quickly, in less than a day or two, there is no time for elements to bond forming minerals.

22. Elements are frozen in place. The minerals have enough time to form but not time to grow into large crystals.

23. PumiceObsidian Scoria

24. Igneous Rock Review

25. Textures Glassy Instanteous Cooling No Grains

26. Textures Aphanitic Quick Cooling Fine Grains

27. Phaneritic Slow Cooling Course Grain

28. Mineral Percentage

30. Lab: Mineral Percentages

31. Magma Chemistry Felsic Magma is thick and slow moving. Has large amounts of silica (SiO 2 ).

32. Mafic Magma is hotter, thinner and more fluid. Has lower amounts of silica (SiO 2 ).

33. Intermediate

34. Ultramafic Large amounts of iron and magnesium.

36. Lab: Classifying Igneous Rocks-Interactive

37. Lab: Classifying Igneous Rocks

38. Sedimentary Rock Formed by layers of sediments.

39. Bits of rock, and deposits them on the bottom of the river bed.

40. Deposited rocks build up in layers, and the weight of the top layers compresses the bottom layers.

41. The compression squeezes out water, leaving salt crystals that cement the rocks together.

42. Lab: Sand

45. Clastic Sedimentary Rock Are composed of pieces of rock, minerals, or fossils that have been cemented together. Sandstone is an example.

47. Fossils

48. Chemical Sedimentary Rock Chemical sedimentary rocks form by precipitation or the growth of new minerals in water.

49. Precipitation can create large sedimentary structures like stalactites and stalagmites, which grow in caves.

50. Organic Sedimentary Rock

51. Lab: Classifying Sedimentary Rocks

53. Metamorphic Rock

54. Metamorphic Rock Formation

56. Contact Metamorphism Magma comes in contact with an already existing body of rock.

57. The existing rocks temperature rises and also becomes infiltrated with fluid from the magma.

58. Under the intense heat, existing rocks begin to melt and eventually recrystallize as new species that are stable at higher temperatures.

59. Contact metamorphism produces non-foliated (rocks without any cleavage) rocks such as marble, quartzite, and hornfels.

60. High Temperature-Low Pressure Metamorphism

61. Metamorphic Rock Formation Dynamic Metamorphism

62. Dynamic Metamorphism Dynamic Metamorphism also occurs because of mountain-building.

63. The mineral grains in rocks subjected to extreme pressure often rearrange themselves in a parallel fashion, creating a foliated texture.

64. These huge forces of pressure cause the rocks to be bent, folded, crushed, flattened, and sheared.

65. Contact Metamorphism High Temperature-Low Pressure Metamorphism Dynamic Metamorphism High Pressure-Low Temperature Metamorphism

66. Metamorphic Rock Formation Regional Metamorphism

67. Regional Metamorphism The metamorphosed area can cover thousands of square kilometers. Rock in a mountain- building region is transformed by both heat and pressure.

69. Contact Metamorphism High Temperature-Low Pressure Metamorphism Dynamic Metamorphism High Pressure-Low Temperature Metamorphism Regional Metamorphism Pressure & Temperature Metamorphism

72. Hydrothermal Metamorphism

73. Slate Schist Gneiss Sometimes rocks are metamorphosed just a little bit. Other times, rocks are altered intensely.

74. The degree that rocks are changed by metamorphism depends on how much heat and pressure they are put under, and for how long they are subject to these conditions.

75. The amount of metamorphism is called the Metamorphic Grade.

76. Millions of years after a rock has been metamorphosed, geologists can figure out how much heat and pressure it was subject to by looking at its minerals.

77. Non-Foliates Non-Foliates are metamorphic rocks that have no cleavage at all, do not have wavy layers.

78. Nonfoliated Textures Hornfils

79. Foliates Foliates are composed of large amounts of micas and chlorites. These minerals have very distinct cleavage.

80. Foliated metamorphic rocks will split along cleavage lines that are parallel to the minerals that make up the rock.

82. Foliated Textures

83. Slaty Finely crystalline rock in which minerals, such as mica, are aligned paralle to one another, which means that the rock splints readlily along the mica cleavage planes.

84. Schistose Minerals are aligned in easily visible parallel bands and, because of their platy alignment, the rock splits easily.

85. Gneissose Characterised by a coarse foliation with individual bands several centimeters across. The foliation may wrap around larger crystals. All the minerals are coarsely granular and readily identifiable.

86. Phyllitic This texture is formed by the parallel arrangement of platy minerals, usually micas, that are barely macroscopic (visible to the naked eye).

87. Lab: Metamorphic Rock Classification

88. Lab: Classifying Metamorphic Rocks

89. Porphyroblasts Crystals grow quite large surrounding materials remain small.

92. Lab: Rock Hound