Structural Geology of Rocks and Regions

George H. Davis is the Provost and Regents Professor of the Geosciences, University of Arizona.?He received his Ph.D. in Economic Geology from The University of Michigan, Ann Arbor, and his MA in Structural Geology from The University of Texas, Austin. Stephen J. Reynolds is Associate Professor of Geology, Arizona State University. He received his masters and Ph.D. in Geosciences from the University of Arizona. Dr. Reynolds has received the ASU Department of Geology Outstanding Teacher Award three times and has been nominated for the College of Liberal Arts and Sciences Distinguished Teaching Award, 1993.

• P A R T 1 FUNDAMENTALS 1 CHAPTER 1 Nature of Structural Geology 2Motivation and Context 2Practical Applications 5Field Work 7“Deformation” is the Heart of the Matter 7Architecture and Structural Geology 16Plate Tectonics and Structural Geology 18The Fundamental Structures 21Concept of Detailed Structural Analysis 29The Time Factor 32CHAPTER 2 Displacement and Strain 34Transformations 34Displacement Vectors and Deformation 35Kinematics 36Deformation and Kinematics in Active Tectonic Settings 40Translation 44Rotation 53Strain 59Coaxial and Noncoaxial Strain 78Three-Dimensional Strain Analysis 84On to Dynamics 89CHAPTER 3 Force, Stress, and Strength 90Introduction 90Dynamic Analysis 91Force 95Tractions 101Stress 106Determining Relationships between Stress and Strain 120Conducting Deformation Experiments in the Laboratory 128Evaluating Mechanical Behavior During Testing 138Conclusions 147CHAPTER 4 Deformation Mechanisms and Microstructures 148Exploring at the Fine Scale 148Crystalline Structure and the Strength of Solids 149Slip Systems and Bonding 152Deformation Mechanisms 157Deformation Experiments 181The BrittleDuctile Transition 188A Few Final Thoughts 191P A R T 2 STRUCTURES 192CHAPTER 5 Joints 193Definitions and Distinctions 193Glimpse of Joint Formation in Response to Loading and Stress 201Detailed Look at Individual Joint Surfaces 204Growth of Joint Sets 212Joint Spacing in Relation to a Single Bed 216Joint Saturation and Joint In-Filling 223Creation of Joints in the Laboratory 226Influence of Pore Fluid Pressure on Jointing 230A Microscopic Look at the Mechanics of Jointing 236Examples of Interpreting Regional Joint Patterns 239Opportunities in Fracture Analysis 247CHAPTER 6 Faults 249Introduction 249Recognizing Faults: The Physical Character of Faults 251Brittle Fault Rocks 260Map and Subsurface Expressions of Faults 267The Naming and Classification of Faults 272Determination of Slip on Faults 278Strain Significance of Faults 281Mechanics of Faulting 286Thrust Fault Systems 305Normal Faulting 321Strike-Slip Faulting 334Concluding Remarks 343CHAPTER 7 Folds 344Incentives for Study 344Anticlines and Synclines 351Geometric Analysis of Folds 358Transition from Geometry to Dynamics 383Buckling 384Flexural Folding 390Kink Folding 397Passive Folding 401Regional Tectonic Folding 403Conclusions 404CHAPTER 8 Fault-Fold Interactions 405Incentives for Even Further Study 405General Model of Fault-Related Folding 407Assumptions About Dip Domains and Fault-Related Folds 408Fault-Bend Folds 409Fault-Propagation Folds 414Fault-Related Folding Created Through Stretching 428Salt-Related Structures 433Structural Inversion 443Folds Associated With Strike-Slip Faulting 447Role of Structural Development in Sedimentation 449Structural Balance 452Small-Scale Structures, and Scaling 459Concluding Thoughts 461CHAPTER 9 Foliation and Lineation 463Nature of Foliation and Lineation 463Nature of Cleavage 465Microscopic Properties of Cleavage and Schistosity 472Strain Significance of Cleavage 475Relationship of Cleavage to Other Structures 487Foliation 492Lineation 501Descriptive/geometric Analysis of Foliation and Lineation 511Strain, Shearing, and Fabric Development 515Estimating Strain 520“Tectonite-Forming” Geologic Settings 526On to Shear Zones 529CHAPTER 10 Shear Zones and Progressive Deformation 530The Nature of Shear Zones 530Types of Shear Zones 540Why Shear Zones Form, Thin, and Thicken 546Strain in Shear Zones 548Determining Sense of Shear 556Fabric Development and its Relation to the Amount of Strain in Shear Zones 577Inside the Ellipse: Progressive Deformation 586On to Active Tectonics 598CHAPTER 11 Active Tectonics 599Structural Geology and Active Tectonics 599Plan of Action for This Chapter 600Western United States 603The San Andreas Fault 606The Los Angeles Basin 616The Eastern California Shear Zone 627Relation To Cascadia, American Northwest 649The Basin and Range 656The Wasatch Front 666The Hurricane Fault 673Finishing Up 677Summing Up 680P A R T 3 DESCRIPTIVE ANALYSIS: HOW TO FUNCTION IN THE FIELD, AND HOW TO REDUCE THE DATA 683A. Nature of Descriptive Analysis 684B. Geologic Mapping 687C. Mapping Contact Relationships 697D. Identifying Primary Structures 706E. Measuring the Orientations of Structures 711F. Preparing Geologic Cross-Sections 718G. Preparing Subsurface Contour Maps 726H. Using Orthographic Projection 728I. Carrying Out Stereographic Projection 735J. Evaluating Rotation Using Stereographic Projection 751K. Determining Slip on a Fault through Orthographic and Stereographic Projection 757L. Carrying Out Strain Analysis 760M. Determining the Relationship ofFaults to Principal Stress Directions 767N. Carrying Out Joint Analysis 769O. Engaging in Fault Analysis 778P. Carrying Out Fold Analysis 779Q. Deciphering Structure in Boreholes 785R. Studying Shear Zones in the Field 790S. Determining Focal Mechanisms for Earthquakes 793REFERENCES 799AUTHOR INDEX 823SUBJECT INDEX 829