STRUCTURAL ANALYSIS & SYNTHESIS
STRUCTURAL ANALYSIS & SYNTHESIS A LABORATORY COURSE IN STRUCTURAL GEOLOGY
Structural Analysis and Synthesis is the best-selling laboratory manual of its kind. Specifically designed to support the laboratory work of undergraduates in structural geology courses, the book helps students analyze the various aspects of geological structures, and to combine their analyses into an overarching synthesis.
This book is intended for use in the laboratory portion of a first course in structural geology. As is explicit in the book's title, it is concerned with both the analysis and synthesis of structural features. In this fourth edition, the has been broadened to include a range of new content and features, including:
* Video content that demonstrates how to perform some of the more challenging structural geology techniques
* An acknowledgment of the increasing importance of environmental applications of structural geology - vital to students who may go on to pursue careers in the environmental sphere
* An increased emphasis on quantitative techniques, complete with descriptions of computer program applications
* Contingent with this quantitative emphasis, the book also outlines the limitations of such techniques, helping students to appropriately apply the techniques and evaluate their trustworthiness
Structural Analysis and Synthesis is a renowned and widely recognized aid to students in grasping and mastering the techniques required in structural geology, and will find a home wherever the principles and practices of structural geology are taught.

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 (¿) 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 TwöTilt 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/¿ Method 127

10 Brittle Failure 131

Objective 131

Quantifying TwöDimensional 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