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22 Cards in this Set
- Front
- Back
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Orgeny (Orogenesis) |
-Mostly occur along plate margins |
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Deformation |
-A term for all changes in the original forms or size of a rock body -Mostly occur along plate margins -Caused by tension (pulling apart) or compression (pushing together) |
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Folds: Anticline |
Upfolded or Arched Strata
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Folds: Syncline |
Downfolded Strata
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Plunging Anticlines & Synclines |
Plunging folds die out in one direction
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Symmetrical & Asymmetrical |
Symmetrical- Limbs are mirror images
Asymmetrical- Limbs are not mirror images Overturned- One limb is tilted beyond the vertical |
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Domes |
-More or less circular -Upwarped -Oldest rocks in center Ex. Mount Elden, AZ |
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Basins |
-More or less circular -Downwarped -Youngest rocks in center Ex. Death Valley |
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Faults |
Fractures in rocks where appreciable displacement has taken place.
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Hanging Wall |
The rock above the fault surface
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Footwall |
The rock below the fault surface
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4 Types of Faults |
-Normal -Reverse -Thrust -Strike-Slip |
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Normal Fault |
Hanging wall block moves down caused by tensional forces
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Reverse Fault |
-Hanging wall black moves up
-Caused by compressional forces -Dips greater than 45 degrees |
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Thrust Fault |
Same as reverse fault, but dips less than 45 degrees
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Strike-Slip Fault |
A fault along which displacement is horizontal.
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Transform Faults |
Large strike-slip that cuts through the lithosphere. |
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Joints |
-A fracture in rock along which there has been no appreciable displacement -Not Faults |
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Continental Accretion & Terranes |
Small crustal fragments collide with and accrete to continental margins. Accreted crustal blocks are called terranes. Ex. Along North America's Pacific Coast |
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Buoyancy of the Continentals and Isostasy, as applied to mountain ranges, as they erode. |
The Earth's crust floats in gravitational balance. When weight is removed from the crust, uplift occurs. This process is called isostatic adjustment.
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The Laramide Rockies |
-Major tectonic event that formed the RockyMountains -Occurred 70-40 million years -Occurred in the interior of a plate -Occurred 1,000 miles from nearestsubduction zone |
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Orogenisis |
Refers to the processes that produce a mountain belt |
