Download Structural Geology Review

Structural Geology Review – Definitions & Concepts for which you should have a
working knowledge.
PRIMARY & GEOPETAL STRUCTURES
• Primary Sedimentary Structures: Stratigraphy,
sedimentary structures, unconformities
• Primary Igneous Structures: Pillow lavas, chilled
margins, flow-top breccias, graded phase layering
SECONDARY STRUCTURES
• Fractures/Joints: Mode I, II, III
• Faults: Types
• Fault Rocks
• Folds: geometric description, classification
• Folds: Kinematic models of folding (e.g., flexural
slip, passive shear, etc.)
• Shear zone rocks
• Planar & linear fabrics (e.g., beds, foliations,
lineations, etc.
ORIENTATION
• Strike, dip
• Trend, plunge
• Azimuth vs. quadrant
• Brunton compasses
• Stereographic analysis
• Importance of geologic maps & cross sections &
3-D visualization
RHEOLOGY – the relationship between stress,
strain rate, pressure, temperature, viscosity, etc.
• Brittle Deformation • f(pressure, differential stress, pore fluids, thermal
stress, composition, anisotropy)
• Loss of cohesion
• Ductile Deformation
• No loss of cohesion at crystal/grain scale or larger
• f(temperature, fluid presence, strain rate,
composition)
• Plastic Deformation (intra-crystalline deformation –
within crystal deformation
• f(temperature, fluid presence, strain rate,
composition)
KINEMATIC COMPATIBILITY
• Are structures of diverse geometries/orientations
compatible with a single kinematic model for
structural evolution?
• Examples: Mode II fractures, mid-ocean ridges &
transform faults, folding
STRESS & STRAIN (DYNAMICS & KINEMATICS)
• Stress; graphic representation on Mohr circles
• Strain
• Finite/Total vs. incremental strain
• Strain Ellipsoid
• Non-coaxial flow
• Co-axial flow
• Simple shear
• Pure shear
• General shear
• Transpression, transtension
EARTH’S TECTONIC ELEMENTS
• Crust: oceanic vs. continental; thicknesses,
composition
• Lithosphere & lithospheric mantle
• Asthenosphere: composition, physical state,
rheology
PLATE TECTONICS
• Sea-floor spreading at mid-ocean ridges &
marginal basins
• Subduction zones, volcanic/magmatic arcs
• Transform faults
• Ophiolites, serpentinites, suture zones
STRUCTURAL SETTINGS WE MAY STUDY
Fold & Thrust Belts:
Pyrenees
Alps
Himalaya
Andean
Cordilleran (US/Canada/Mexico): Sevier,
Laramide, Ancestral Rockies
Icy satellites
Detachment faulting and highly extended terranes,
“Core Complexes”:
US Cordillera
Greece
D’entrecastreau Islands
Slow spreading oceanic
Transform Faults:
San Andreas Fault
Anatolian Fault