Geologic StructuresStructural Geology – study of deformation of
rocks and the forces that cause deformation
Structural Geology is concerned with deformation of the Earth's crust
Where is deformation occurring today? • Plate boundaries • Active orogenic belts • (Impact structures)
Where has deformation occurred in the past? • Identify ancient orogens • Relative ages of rocks vs. deformation
Why do we want to understand deformation? • Natural hazards • Economic resources • Basic science
The tectonic plates
Geologic StructuresStress – Compression,
Tension, Shear
Stress – Strain relationsStrain – Elastic, Plastic, Brittle
Elastic range
Geologic Maps
Geologic Maps – strike & dip (angle, direction), geologic cross-sections
http://www.visualentities.com/applets/blockdiagram.htm
Geologic MapsFolds – antiforms, synforms, limbs, hinge line (axis), axial plane, domes, basins,
Folds
Domes
Truncated Dome
Folds
Plunging folds, domes, basins
Types of foldsOpen, isoclinal, overturned, recumbent
Joints, cracks, fracturesTensional, compressional, sets
Joints, cracks, fractures
Several sets
“Anticracks” – pressure solutionStylolites
FaultsFault plane, hanging wall, footwall
Faults – dip-slip, strike-slip, oblique-slip
Fault planesDip-slip – normal, reverse
Dip-slip – normal (horst & graben)
Dip-slip – normal fault zone, Iran
Pliocene-Pleistocene, Zanjan-Tabriz highway
Dip-slip – reverse (thrust)
Strike-slip & Oblique-slip
כיווני מאמץ והעתקים
התקצרות – חיוביתהתארכות - שלילית
Strike-slip faulting features
כיווני מאמץ ראשיים והעתקים
התקצרות – חיוביתהתארכות - שלילית
Geologic StructuresMining
Geologic Structures
Oil Reservoirs
Oil Reservoirs
Oil Reservoirs