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Geology 3120 - A structural geology primer. Outline. Stress Lithology Strength Deformation styles Geologic time Deformation movements Attitudes Scaling Relationships Examples . Stress. Stress = (Force / Area). Shear. Tensile. Compressive. y. x. Lithology. Most stiff.
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Outline • Stress • Lithology • Strength • Deformation styles • Geologic time • Deformation movements • Attitudes • Scaling Relationships • Examples
Stress Stress = (Force / Area) Shear Tensile Compressive y x
Lithology Most stiff Granite Dolomite Arkose Quartz Sandstone Greywacke Coarse grained limestone Fine grained limestone Siltstone Marl, mudstone Shale Anhydrite Halite Least stiff (fluid)
Strength of rock Strength Depth • In addition to lithology, strength is a function of pressure, temperature, pre-existing weakness, chemical reactions, time
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
Deformation Styles Ductile N Brittle
Deformation Movements BEFORE AFTER
Attitudes Planes Faults Bedding Contacts Lines Slickenlines and grooves Mineral growth Piercing points
Scaling Relationships Displacement (D) Length (L)
Examples • Faults • Folds • Joints • Dikes • Shear zones • Extensional veins
Faults Black Mountains, Death Valley
Faults Black Mountains, Death Valley
Folds Carboniferous limestones beds, Grenoble, France
Folds Carboniferous limestones beds, Grenoble, France
Joints Joints in the Sandstone, Moab region
Dikes Granite dikes, Dillon, CO
Dikes Granite dikes, Dillon, CO
Shear zones San Gregario fault zone, California
Shear zones San Gregario fault zone, California
Extensional Veins Calcite-filled veins, French Alps
Extensional Veins Calcite-filled veins, French Alps