geologic structures structural geology – study of deformation of rocks and the forces that cause...

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