1. The Rock Cycle

2. Ag Earth Science – Chapter 3.1
3.1 Vocabulary

3. mineral
A natural occurring, inorganic crystalline material with a unique chemical composition.

4. rock
A consolidated mixture of minerals

5. igneous rock
A rock formed by the crystallization of molten magma

6. sedimentary rock
Rock formed by from weathered products of preexisting rocks that have been transported, deposited, compacted, and cemented.

7. metamorphic rock
Rock formed by the alteration of preexisting rock deep within the Earth by heat, pressure, and/or chemically active fluids.

8. rock cycle
A model that illustrates the origin of the three basic rock types and the interrelatedness of Earth materials and processes.

9. magma
A body of molten rock found at depth including any dissolved gases and crystals.

10. lava
Magma that reaches the Earth’s surface.

11. weathering
The disintegration and decomposition of rock at or near the Earth’s surface.

12. sediments
Loose particles created by weathering and erosion of rock, by chemical precipitation from solution in water, or from the secretions of organisms and transported by water, wind, or glaciers.

13. Rocks
A rock is any solid mass of mineral or mineral-like matter that occurs naturally as part of our planet.
Rocks are classified into 3 major types
Igneous Rocks
Sedimentary Rocks
Metamorphic Rocks

14. The Rock Cycle
Interactions among the Earth’s water, air, and land can cause rocks to change from one type to another
The continuous processes that cause rocks to change make up the rock cycle
When magma (molten material beneath the Earth’s surface) cools and hardens, igneous rocks form. Magma that reaches the surface is called lava.

15. When weathered (process by which rocks are physically and chemically broken down into small pieces called sediments) sediments are compacted and cemented together, they form sedimentary rocks.
When sedimentary rocks are subjected to extreme pressure and heat, they change in metamorphic rock.

16. The Rock Cycle

17. Powers of the Earth’s Rock Cycle
Heat from the Earth’s interior are responsible for forming both igneous and metamorphic rocks
Weathering and the movement of weathered materials are generated by the sun’s energy and produce sedimentary rock.

18. Ag Earth Science – Chapter 3.2
3.2 Vocabulary

19. ignis
Latin word for “fire”

20. intrusive igneous rock
Igneous rock that formed below the Earth’s surface

21. extrusive igneous rock
Igneous rock that has formed on the Earth’s surface

22. porphyritic texture
An igneous texture consisting of large crystals embedded in a matrix of much smaller crystals

23. granitic composition
A compositional group of igneous rocks that indicate a rock is composed entirely of light-colored silicates, mainly quartz and feldspar

24. basaltic composition
A compositional group of igneous rocks indicating that the rock contains substantial dark silicate minerals and calcium-rich plagioclase feldspar

25. andesitic composition
A composition of igneous rocks lying between felsic and mafic

26. ultramafic
Igneous rock composed mainly of iron and magnesium-rich minerals

27. Formation of Igneous Rocks
Igneous – Comes from the Latin word “ignis” which means “fire”

28. Formation of Igneous Rocks
Intrusive Igneous Rocks – rocks that form when magma hardens (cools) beneath the Earth’s surface.
Example – Granite

29. Formation of Igneous Rocks
Extrusive Igneous Rocks – rocks that form when lava hardens (cools) above the Earth’s surface.
Example – Rhyolite

30. Classification of Igneous Rocks
Texture and composition are two characteristics used to classify igneous rocks.

31. Classification of Igneous Rocks
Course Grained Texture – Slow cooling = large crystals. Large crystals exhibit “course-grained” texture.

32. Classification of Igneous Rocks
Fine Grained Texture – Rapid cooling = small mineral grains. Small grains are said to have “fine-grained” texture.

33. Classification of Igneous Rocks
Glassy Texture – Lava spews on surface = may not be time for ions to arrange themselves into crystals. Random distributed ions = glassy texture.

34. Classification of Igneous Rocks
Porphyritic Texture – Large body of magma may take thousands of years to harden. Variety of temperature/cooling within large mass = large crystals and fine-grained minerals.

35. Classification of Igneous Rocks
Granite Composition – Made almost entirely of light colored silicate minerals quartz and feldspar.

36. Classification of Igneous Rocks
Basaltic Composition – Rocks that contain many dark silicate minerals and plagioclase.

37. Classification of Igneous Rocks
Andesitic Composition – In-between granite (light) and basaltic (dark) compositions.

38. Classification of Igneous Rocks
Ultramafic – Composed almost entirely of dark silicate minerals (peridotite).

39. Classification of Igneous Rocks

40. Ag Earth Science – Chapter 3.3
3.3 Vocabulary

41. erosion
The incorporation and transportation of material by a mobile agent such as water, wind, or ice.

42. deposition
The process by which an agent of erosion loses its energy and drops the sediment it is carrying.

43. compaction
Process by which sediments are squeezed together by the weight of overlying materials driving out water.

44. cementation
Solidification of sediments by deposition of dissolved minerals

45. clastic sedimentary rock
A sedimentary rock made of broken fragments of existing rock

46. chemical sedimentary rock
Sedimentary rock consisting of material that was precipitated from water by either inorganic or organic means

47. Formation of Sedimentary Rocks
Sedimentary – Comes from the Latin word “sedimentum” which means “settling”

48. Formation of Sedimentary Rocks
Weathering, Erosion, and Deposition
Erosion – involves weathering and the removal of rock
When an agent (wind, ice, water, or gravity) loses energy, it drops the sediments.
Deposition – the process of erosion losing energy and dropping sediment.

49. Formation of Sedimentary Rocks
Compaction and Cementation
Compaction – process of “squeezing” or compacting sediments
Cementation – dissolved minerals are deposited in the tiny spaces among sediments.

50. Formation of Sedimentary Rocks
The 5 Main Processes that Form Sedimentary Rocks
weathering
erosion
deposition
compaction
cementation

51. Classification of Sedimentary Rocks
Clastic Sedimentary Rocks – Made up of weathered bits of rocks and minerals

52. Classification of Sedimentary Rocks
Classified according to particle size
Conglomerate –(gravel) rounded, large gravel-size or larger pebbles cemented together
Breccia – (gravel) angular particles
Sandstone – sediments are sand-sized grains
Siltstone – fine-grained sediments

53. Classification of Sedimentary Rocks
Chemical and Biochemical Sedimentary Rocks – form when dissolved substances precipitate, or separate, from water solution.
Examples – limestones, rock salt, chert, flint, and rock gypsum.

54. Features of Some Sedimentary Rocks
The many unique features of sedimentary rocks are clues to how, when, and where the rocks formed.
Each layer is a “time period”
Fossils are unique in sedimentary rocks

55. Ag Earth Science – Chapter 3.4
3.4 Vocabulary

56. metamorphism
The changes in mineral composition and texture of a rock subjected to high temperatures and pressure within the Earth

57. contact metamorphism
Changes in rock caused by the heat from a nearby magma body

58. regional metamorphism
Metamorphism associated with large-scale mountain building

59. hydrothermal solution
The hot, watery solution that escapes from the mass of magma during later stages of crystallization

60. Formation of Metamorphic Rocks
Metamorphism – “to change form”
Formation of Metamorphic Rocks
Most metamorphic changes occur at elevated temperatures and pressures.
These conditions are found a few kilometers below the earth’s surface and extend into the upper mantle

61. Formation of Metamorphic Rocks
Types of Metamorphism
Contact Metamorphism – Hot magma moves into rock
Regional Metamorphism – large scale deformation and high-grade metamorphism due to extreme pressures and temperatures. (Example – mountain building)

62. Agents of Metamorphism
The agents of metamorphism are heat, pressure, and hydrothermal solutions

63. Agents of Metamorphism
Heat – Most important agent of metamorphism. Provides energy for chemical reactions. Heat comes from magma and change in temperature with depth.

64. Agents of Metamorphism
Pressure (Stress) – Increases with depth (example – bottom of swimming pool). Pressure causes spaces between minerals to close = greater density.

65. Agents of Metamorphism
Reactions to Solutions – solutions that surround mineral grains aid in recrystallization by making it easier for ions to move. When hot, water-based solutions escape from magma, they are called hydrothermal solutions. These hot fluids promote recrystallization.

66. Classification of Metamorphic Rocks
The texture of metamorphic rocks can be foliated or nonfoliated

67. Classification of Metamorphic Rocks
Foliated Metamorphic Rocks – a texture that gives the rock a layered appearance

68. Classification of Metamorphic Rocks
Nonfoliated Metamorphic Rocks – a texture that does not exhibit a banded or layered appearance.