Geology 3120 A structural geology primer

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Geology 3120 - A structural geology primer
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Outline

• Stress
• Lithology
• Strength
• Deformation styles
• Geologic time
• Deformation movements
• Attitudes
• Scaling Relationships
• Examples

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Stress
Stress (Force / Area)
Shear
Tensile
Compressive
y
x
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Lithology
Most stiff
Granite Dolomite Arkose Quartz Sandstone Greywacke
Coarse grained limestone Fine grained
limestone Siltstone Marl, mudstone Shale
Anhydrite Halite
Least stiff (fluid)
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Strength of rock
Strength
Depth

• In addition to lithology, strength is a function
  of pressure, temperature, pre-existing weakness,
  chemical reactions, time

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Regarding Geologic Time

• Page 36
• Required knowledge Eras, Periods
• Eras - Paleozoic (540-248 My) Mesozoic (248-65
  My) Cenozoic (65-0 My)
• Periods - COSDMPP TJK
• TQ

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Deformation Styles
Ductile
N
Brittle
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Deformation Movements
BEFORE
AFTER
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Attitudes
Planes Faults Bedding Contacts
Lines Slickenlines and grooves Mineral
growth Piercing points
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Scaling Relationships
Displacement (D)
Length (L)
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Examples

• Faults
• Folds
• Joints
• Dikes
• Shear zones
• Extensional veins

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Faults
Black Mountains, Death Valley
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Faults
Black Mountains, Death Valley
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Folds
Carboniferous limestones beds, Grenoble, France
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Folds
Carboniferous limestones beds, Grenoble, France
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Joints in the Sandstone, Moab region

• Joints

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Dikes
Granite dikes, Dillon, CO
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Dikes
Granite dikes, Dillon, CO
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Shear zones
San Gregario fault zone, California
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Shear zones
San Gregario fault zone, California
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Extensional Veins
Calcite-filled veins, French Alps
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Extensional Veins
Calcite-filled veins, French Alps