Structural Geology and Rock Mechanics

• Important Terms

  • Bed
  • Strata
  • Stratigraphy
  • Outcrop
  • Azimuth
  • Quadrant
• Strata


  • A layer of rock or sediment characterized by certain lithological properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as either bedding surfaces or bedding planes
• Stratigraphy


  A branch of geology concerned with the study of rock layers and layering
• Outcrop


  An exposure of a solid rock on the surface of the Earth
• Azimuth


  A compass direction of the line measured in degrees (0° - 360° clockwise from North with (North = 0°, East = 90°, South = 180°, and West = 270°)
• Quadrant


  A compass direction measured 0° to 90° form north or south
• Two Types of Views

  • Map View/Top View
  • Cross-Sectional View
• Attitude


  A general term for the orientation of a line or plane
• Attitude of Beds

  • Planar Attitude
  • Linear Attitude
• Planar Attitude


  Defined by the strike and dip
• Linear Attitude


  The attitude of linear structure is defined by the Trend and Plunge
• Pitch/Rake


  The acute angle between the line and the strike of the plane on which the line lies
• Brunton Compass


  A specialized instrument used widely by those needling to make an accurate degree and angle measurements in the field
• Outcrop


  A rocky exposition on the Earth's surface but usually occurs as vertical walls (cliffs, quarries, mine faces, road sections, etc.)
• Outcrop Patterns


  • Flat - Lying Bed
  • Plunging Folds
  • Rule of V's
• Two Kinds of Outcrops


  • Natural Outcrops
  • Outcrops cause by Human activities
• Geological Map


  A specialized type of map that depicts the geological features and formations of a particular area
• Elements of Geological Maps

  • Base Map
  • Legend and Formation Label
  • Color
  • Fault Lines
  • Fold Lines
  • Strike and Dip Lines
  • Geologic Cross-Section
• Types of Geological Map

  • Surface Geological Map
  • Structural Map
  • Mineral Map
  • Geological Hazard Map
• Geologic Structure


  Structures often formed by powerful tectonic forces deep within the Earth. These forces can fold and fracture rocks, creating features like faults and folds
• Two Types of Geologic Structure

  • Primary Structure
  • Secondary Structure
• Primary Structure


  • A structure that developed during the formation of the rocks
• Secondary Structure


  • A structure that developed in a sedimentary or igneous rock after lithification and in metamorphic rocks during or after their formation
• Parts of Folds

  • Axis of fold
  • Axial plane
  • Limbs of a fold
  • Crest and Trough
  • Wavelength of a fold
• Classification of Folds

  • Symmetrical Fold
  • Asymmetrical Fold
  • Overturned Fold
  • Recumbent Fold
  • Chevron Fold
• Types of Folds

  • Anticline
  • Syncline
  • Monocline
  • Domes and Basins
• Types of Faults

  • Normal Fault
  • Reverse Fault
  • Strike-Slip Fault
  • Oblique Fault
• Joints


  Any Fracture, without any movement
• Classification of Joints

  • Geometric Classification
  • Genetic Classification
• Rock Mechanics


  A branch of geomechanics that focuses on studying the behaviour of rocks and how they respond to various forces and condition
• Physical Properties

  • Density
  • Porosity
  • Permeability
  • Mineral Composition
• Mechanical Properties

  • Compressive Strength
  • Tensile Strength
  • Shear Strength
  • Poisson's Ratio
  • Young Modulus
• Types of Tensile Strength

  • Yield Strength
  • Ultimate Strength
  • Breaking Strength
• Manners of Tensile Failure

  • Ductile Failure
  • Brittle Failure
• Hardness


  The hardness property of rocks refers to their resistance to scratching, abrasion, or indentation
• Elasticity


  The elasticity of rocks refers to their ability to deform reversibly under stress and then return to their original shape once the stress is removed
• a branch of geology that deals with the form, arrangement, and internal structure of rocks

  Structural Geology and Rock Mechanics
• Bed


  a layer of sediments or rocks such as coal, that extends under a large area and has a distinct set of characteristics that distinguish it from other layer below and above it.