Folds Faults and Other Records of Rock Deformation
- Slides: 45
Folds, Faults and Other Records of Rock Deformation Ch. 11 Grotzinger, Jordan Press & Siever
Concepts you will need to know for the exams • • • • • • Deformation Normal fault Thrust/Reverse Fault Strike-slip Fault folds Stress tension compression shearing Factors athat determine the amount and type of deformation in a rock Temperature Fluids Pressure How fast materials are deformed Composition Time Fault breccia--- a example of brittle rock deformation Mylonite ----- an example of plastic deformation Joints fracturs and faults Anticlines and Synclines Dome, Valley and Ridge (TN) topography
A fold is a bend in a rock… But, how can this be? ? “Inequality is the cause of all local movements” LEONARDO DA VINCI (1452 -1519)
A fault is a break in a rock across which there is observable movement. When the break occurred an earthquake was generated, whether or not anyone was there to detect it. Sometimes faults die at depth and do not break the surface. Sometimes they do such as for the Armenia 1988 earthquake.
Directed pressure (cf. confining) in the earth leads to deformation if it is great enough. Rocks deform under three orientations for the directed pressure or STRESS.
The directed stress can have three orientations with respect to vertical: (Side view) (Side View) (Bird’s Eye View)
If the sediments are “soft” and folds develop: (Side view) (Side View) L H O I WG S H S L O W S H I G H S L O (Bird’s Eye W View) S
If the sediments are brittle faults can develop: (Side view) (Side View) (Bird’s Eye View)
If the sediments are brittle faults can develop: (Side view) (Side View) (Bird’s Eye View)
What is the direction of directed pressure? How many orientations of faults can be generated for the same directed pressure direction? ?
If the sediments two possible orientations for faults can develop: (Side view) (Side View) (Bird’s Eye View)
At least 6 factors control how rock deforms e. g. at shallow depth a rock may fracture whereas at depth it may flow. Factors are: (1) rock type (2) Confining and directed pressure (3) temperature (4) Fluids (5) Time (6) Rate of deformation
Brittle: Means a rock breaks quickly into sharp pieces, e. g. glass at room temperature Textures show that rocks break in a brittle fashion at shallow depths inside faults (I. e. fault breccia, fault flour)
Ductile-- Means that a rock breaks slowly, or has a lot of “give” Textures show that rocks break in a ductile fashion at depths of a few kilometers inside faults. The minerals recrystallize, and grow into new shapes
Joints are also fractures, but which do not show clear movement of blocks across them. ( Remember: Faults are also fractures but WITH movement across the fractures)
Different types of faults imply different directions of shortening and lengthening and can be used to imply different types of plate margin settings:
- True vocal folds and false vocal folds
- Folds faults and joints
- Make your own folds and faults
- Elastic compliance
- What does a strike slip fault cause
- Rock folds
- Stress that squeezes rock until it folds or breaks
- Igneous rock to metamorphic rock
- Fold
- Hanging wall vs footwall
- Factors affecting rock deformation
- Anterior and posterior axillary fold
- Anticline and syncline folds
- Nasolabial fold
- Chapter 3 standardized test practice answers
- Chapter 3 standardized test practice answers
- Branches of stratigraphy
- Gastric folds
- Decussate texture
- Osk
- Type of fold: downfolds or troughs
- 13.2 structures of the digestive system
- Kerckring folds
- Deformacion
- Gastric folds in stomach
- Thin
- Absorbent pads for skin folds
- Overlapping skin around the nail
- Buckle folds
- Terminology of folds
- Stomach
- Voueu
- Parts of triangular bandage
- Tympanic membrane diagram
- Respiratory membrane
- These folds shape the epidermis into fingerprints:
- Overfold diagram
- How can one type of rock change into another type of rock?
- Igneous rock to metamorphic rock
- Bungee climbing
- Ciclo de las rocas
- Normal reverse and transform faults
- Examples of little foxes that spoil the vine
- Plastic deformation
- Elastic and plastic deformation
- Fast and deep deformation approximations