About the Authors Stephen M. Rowland is Professor Emeritus of Geology at the University of Nevada, Las Vegas, NV, USA. Ernest M. Duebendorfer is Professor Emeritus of Geology at Northern Arizona University, Flagstaff, AZ, USA. Alexander Gates is Distinguished Service Professor & Chair in the Department of Earth and Environmental Sciences, Rutgers University, Newark, NJ, USA.

Preface vii About the Companion Website ix 1 Attitudes of Lines and Planes 1 Objectives 1 Definitions 2 Structural Elements 4 Structural Grain 5 2 Outcrop Patterns and Structure Contours 9 Objectives 9 Structure Contours 12 The Three-Point Problem 13 Drawing a Topographic Profile 14 Drawing Cross Sections of Structure Contour Maps 15 Determining Outcrop Patterns with Structure Contours 15 Gently Bent Layers 17 Determining Exact Attitudes from Outcrop Patterns 18 Determining Stratigraphic Thickness in Flat Terrain 19 Determining Stratigraphic Thickness on Slopes 20 Determining Stratigraphic Thickness by Orthographic Projection 20 3 Stereographic Projection 31 Objective 31 Plotting a Plane 33 Plotting a Line 33 Plotting the Pole to a Plane 34 Line of Intersection of Two Planes 35 Angles of Lines within a Plane 36 Determining True Dip from Strike and Apparent Dip 37 Determining Strike and Dip from Two Apparent Dips 38 4 Folds and Cross Sections 43 Objectives 43 Glossary of Fold Terms 43 Classification by Shape 45 Classification by Orientation 45 Fold Classification Based on Dip Isogons 47 Outcrop Patterns of Folds 48 Cross or Structure Sections of Folded Layers 49 The Arc Method 50 Down-Plunge Projection 50 5 Stereographic Analysis of Folded Rocks 67 Objectives 67 Beta (ß) Diagrams 67 Pi (pi) Diagrams 68 Pole Plotter 68 Determining the Orientation of the Axial Plane Using Fold Trace 69 Constructing the Profile of a Fold Exposed in Flat Terrain 69 Determining the Orientation of the Axial Plane Without a Fold Trace 70 Simple Equal-Area Diagrams of Fold Orientation 71 Contour Diagrams 71 Determining the Fold Style and Interlimb Angle from Contoured Pi Diagrams 75 6 Rotations and Determining Original Directions in Folded Rocks 87 Objectives 87 Rotation of Lines 87 The Two-Tilt Problem 89 Cones: The Drill-Hole Problem 90 Unfolding Folds 93 7 Foliations, Parasitic Folds, and Superposed Folds 95 Objectives 95 Foliations 95 Parasitic Folds 97 Superposed Folds 99 8 Strain Measurements in Ductile Rocks 107 Objectives 107 Longitudinal Strain 107 Shear Strain 108 The Strain Ellipse 108 Strain Fields 108 The Coaxial Total Strain Ellipse 109 Measuring Strain in Deformed Objects 110 Strain in Folds 111 Deformed Fossils as Strain Indicators 111 Mohr Circle for Sheared Fossils 112 Mohr Circle for Boudinage 113 9 Advanced Strain Measurements 125 Objectives 125 Fry Method 126 Rf/phi Method 127 10 Brittle Failure 131 Objective 131 Quantifying Two-Dimensional Stress 131 The Mohr Diagram 133 The Mohr Circle of Stress 134 Rules for Going Between Mohr Space and Real Space 135 The Failure Envelope 135 The Importance of Pore Pressure 138 11 Analysis of Fracture Systems 147 Objectives 147 Data Collection 148 Rose Diagram 148 Length vs Strike Graphs 149 Interpreting Joint Strike Diagrams 150 Contouring Joint Density 150 Accounting for Dip in Joints 152 12 Faults 157 Objectives 157 Measuring Slip 159 Rotational (Scissor) Faulting 161 Map Patterns of Faults 162 Timing of Faults 163 13 Dynamic and Kinematic Analysis of Faults 169 Objectives 169 Dynamic Analysis 169 Kinematic Analysis 174 14 Structural Synthesis 191 Objective 191 Structural Synthesis 191 Some Suggestions for Writing Style 193 Common Errors in Geologic Reports 193 15 Deformation Mechanisms in Mylonites 197 Objectives 197 Deformation Mechanisms 197 Fault Rocks 200 Kinematic Indicators 202 S-C Fabrics 202 Asymmetric Porphyroclasts 202 Oblique Grain Shapes in Recrystallized Quartz Aggregates 203 Antithetic Shears 203 Strain and Offset in Shear Zones 204 Potential Sources of Error 205 16 Construction of Balanced Cross Sections 213 Objectives 213 Thrust-Belt "Rules" 213 Recognizing Ramps and Flats 214 Relations Between Folds and Thrusts 215 Requirements of a Balanced Cross Section 218 Constructing a Restored Cross Section 219 Constructing a Balanced Cross Section 220 17 Introduction to Plate Tectonics 233 Objectives 233 Fundamental Principles 233 Plate Boundaries 234 Triple Junctions 235 Focal-Mechanism Solutions ("Beach-Ball" Diagrams) 236 Earth Magnetism 240 Apparent Polar Wander 242 18 Virtual Field Trip 253 Objective 253 Newfoundland Folds Field Trip 254 Ramapo Fault Field Trip 255 References 257 Further Reading 259 Index 265