1. Sedimentary and Metamorphic Rocks
Chapter 6

2. Formation of Sedimentary Rocks
Sediments- pieces of solid material that have been deposited on the earth’s surface by water, wind, ice, gravity, or chemical precipitation.
Weathering- a set of physical and chemical properties that break rock into smaller pieces.
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3. Formation of sedimentary Rocks
Clastic sediments- rock and mineral fragments formed by weathering
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4. Formation of Sedimentary Rock
Erosion- the removal and movement of surface materials from one location to another.
Wind
Water (moving)
Gravity
Glaciers
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5. Formation of sedimentary rocks
Deposition- sediments are dropped by the erosional force in a new location causing them to “pile” up on each other.
Largest sedments typically settle out first (bottom)
Small sediments typically settle out last (top)
Not all sediments are sorted-- glaciers
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6. Formation of sedimentary rocks
Burial- sediments are typically deposited on low areas of the earth called sedimentary basins. The sediments layer or “pile” on top of each other causing lithification
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7. Formation of Sedimentary Rock
Litification- physical and chemical process of changing sediment into sedimentary rock
Begins with pressure (weight) of the overlying sediments forcing grains of sediments below close together.
Sediments buried 3-4km below the earth’s surface will experience relatively high temperatures causing cementation.
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8. Formation of sedimentary rock
Cementation- occurs when mineral growth cements sediment grains together into solid rock.
New mineral forms from ground water precipitation.
Existing mineral grows larger
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9. Features of sedimentary rock
Bedding- horizontal layering
Graded bedding- particle size becomes progressively heavier and larger toward the bottom.
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10. Features of sedimentary rock
Cross bedding- formed when inclined layers of sediment move forward across a horizontal surface
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11. Features of sedimentary rock
Fossils- preserved remains, impressions, or any other evidence of once-living organisms
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12. Types of sedimentary rocks
Clastic sedimentary rocks- form from deposited loose sediment
Course grained- gravel-sized rock and mineral fragments (conglomerate)

13. Types of sedimentary Rocks
Clastic
Medium grianed- sand-sized sediments (sandstone)

14. Types of sedimentary rocks
Red Rock Canyon, Nevada
Clastic
sandstone

15. Types of sedimentary rocks
Clastic
sandstone
Balanced sandstone formation at Red Rock Canyon

16. Types of sedimentary rocks
Clastic
sandstone

17. Types of sedimentary Rock
Clastic
Fine grained- silt and clay size particles (shale)

18. Types of sedimentary rocks
Chemical- minerals dissolved in water are left behind when the water evaporates
Evaporites- most common calcite, halite, gypsum

19. Types of sedimentary rock
Chemical
Organic- formed from the remains of organisms (limestone)

20. Metamorphic rock
Metamorphism- change in the combination of minerals in a rock because of added heat and pressure.
Regional metamorphism- metamorphism in a large region of the earth’s crust.

21. Metamorphic Rock
Contact metamorphism- occurs when molten rocks come in contact with other rocks.
Hydrothermal metamorphism- very hot water reacts with rock.
Metamorphic
Sedimentary

22. Metamorphic rock Metamorphic textures- Foliated- wavy layers or bands
Nonfoliated- rocks that lack mineral grains in bands.
Porphyroblasts- some minerals will grow large and be surrounded by other smaller minerals.
Nonfoliated
porphyroblast
foliated
Chlorite and Biotite
Gneiss
Marble

23. Metamorphic rock
Solid state alterations- a mineral changes to a new mineral without melting. 
Granite
Gneiss

24. Rock Cycle