ROCK TYPES

1
ROCK TYPES

• Igneous
• Sedimentary
• Metamorphic

2
ROCK CYCLE

• Not a one-way process

3
IGNEOUS ROCKS

• Form from lava or magma
• Crystallization
• Compaction and cementation of ash
• Two properties
• Texture
• Mineral content

4
TEXTURE

• Intrusive - formed below surface, slow cooling,
  large crystals
• Extrusive - formed at or near surface, fast
  cooling, small crystals
• Porphyritic - large crystals within fine grained
  mass, varied cooling
• Glassy - very rapid cooling, no crystals
• vesicular

5
MINERAL CONTENT

• Felsic (granitic) - light color, less dense
• Intermediate (andesitic) - medium color
• Mafic (basaltic) - mostly dark, dense
• Ultramafic - very dark and dense

6
BOWENS REACTION SERIES

• Minerals crystallize at different temperatures
• Felsic at lower temps, mafic at higher

7
MINERAL CONCENTRATION

• Magmatic differentiation
• Selective crystallization
• Immiscible liquids
• Replacement
• Evaporite
• Placer
• Groundwater enrichment
• Secondary
• Residual

8
SEDIMENTARY ROCKS

• Form from compacted sediments
• Processes
• Weathering and erosion
• Deposition
• Compaction
• Lithification / cementation
• Two types
• Detrital (clastic)
• Chemical

9
DETRITAL SEDIMENATRY ROCKS

• Course grained
• Conglomerate, breccia
• Medium grained
• sandstone
• Fine grained
• siltstone
• Very fine grained
• shale

10
CHEMICAL SEDIMENTARY ROCKS

• Evaporites
• Rock salt
• Precipitates
• chert
• Biochemical
• limestone
• Organic
• coal

11
METAMORPHIC ROCKS

• Meta means change, morph means form
• Formed by heat, pressure, or chemically active
  fluids applied to existing rocks

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METAMORPHIC SETTINGS

• Contact
• Regional

13
Metamorphic Textures

• Foliated
• Visible layers or banding
• Opposing directed forces
• Non-foliated
• No layers
• Multi directional forces

14
ROCK USES

• Metallic ores - Igneous origin
• Pegmatites
• Hydrothermal solutions
• Vein deposits
• Disseminated deposits
• Nonmetallic resources
• Building materials
• Industrial minerals