Transcript Nature of Structural Geology

Overview of Structural Geology
(Chapter 1 in D &R)
Why is it important?
- fundamental discipline in Earth Sciences- “the study
of the architecture of the Earth’s crust”
- geometry is key to many ES applications (oil, mining);
Our goals: (1) to learn how to make structural observations and
present them to others;
(2) to interpret the processes that led to the “final
“product”- the geologic observations.
Primary vs. secondary structures.
Primary: depositional contacts, cross-bedding, ripple markes,
Ropy textures in lavas, mud-cracks;
Secondary: these are the real structures we’re after- and
are due to rock regional deformation. Examples:
Folds, faults, shear zones, etc.
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Structural analysis:
1. Descriptive analysis
2. Kinematic analysis- deformational movements- translations,
rotations,distorsions, etc.
3. Dynamic analysis - interprets the forces and stresses
associated to deformations.
Scale of analysis.
Geologic time scale
4.5 Ga old, structures can be very old. Rates of processes.
Kinematic reconstruction:
Rotations, translations, dilations, distortions
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Dynamic analysis:
- physical models (experimental)
- mathematical models (theoretical)
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Read Chapter 1 in DR
Next: Large scale deformations
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