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Exam 1 Exam 2 Exam 3 Exam 4
Series1
Thrust Faults
What kind of fault is it? Precambrian
Paleozoic
How Thrust belts form
Thrust Belt in a Sandbox
Parts of a Thrust-Belt
Components of a thrust belt
forethrustBackthrust
Basal DetachmentBasement
Origin of Foreland Basins
Asia Topography
Sevier Thrust Belt, Wyoming
•Complex Imbricate fan
•Basement involved def.
•Thin-skin def.
Appalachians
Sequence of deformation
Forward propagation of deformation front
1
1
1
1
2
2
2
3
3
Canadian Rockies Mountain Front
Faults of the Canadian Rockies
Bow andarrow rule
Distribution of Shortening
Mt. Yamnuska, Canadian Rockies- McConnell Thrust
Mt. Yamnuska, Canadian Rockies- McConnell Thrust
Cretaceous foreland basin strata
Cambrian limestone
Dev. Limestone
Palliser Fm.
Cretaceous, Belly River Gp.
Lewis
Thrust
Folded Paleozoic Rocks of the Sawback ranges
Front Ranges
E W
Front Ranges
E W
Rundel Thrust
Pz limestone
Jur-K Kootenay Fm.
Detached folds- Jura Mts.
SaltDetachment surface
Calico Bluff, Eagle, AK
Pop-up Structure- A Faulted Fold
Thrust Breaching the Surface- Landers, CA
Geometry of Thrust Sheets
The shape of the fault plane determines the geometry of the folds
The hanging wall conforms to the shape of the footwall
Fault-bend-fold
Progression
Thrust belt movie
Termination of fault-related fold
Fault-related Folding
Duplex
Thrust belt movie
Duplex Spacing
Duplex Structure in thin-bedded sandstones and shales
Fault-propagation
fold
The fault grows as displacement grows
Map patternsComplicated due to erosion of the thrust sheets
Mechanical Paradox of Thrust Sheets
• Stress required to move a thrust sheet is larger than the strength of the rock
• Like trying to push a Jell-O block across the table
Solutions:
1. Reduce Basal Friction High fluid Pressure
2. The sheet does not move all at once
Role of Fluid Pressure
Like pushing a wrinkle out of a rug
Critical Wedge Growth
Keystone thrust fault, southern Nevada
BBDD