Structural Analysis and Synthesis: A Laboratory Course in Structural Geology

ISBN-13: 9781119535454 / Angielski / Spiralna / 2021 / 288 str.

Stephen M. Rowland; Ernest M. Duebendorfer

Spis treści

Preface viiAbout the Companion Website ix1 Attitudes of Lines and Planes 1Objectives 1Definitions 2Structural Elements 4Structural Grain 52 Outcrop Patterns and Structure Contours 9Objectives 9Structure Contours 12The Three-Point Problem 13Drawing a Topographic Profile 14Drawing Cross Sections of Structure Contour Maps 15Determining Outcrop Patterns with Structure Contours 15Gently Bent Layers 17Determining Exact Attitudes from Outcrop Patterns 18Determining Stratigraphic Thickness in Flat Terrain 19Determining Stratigraphic Thickness on Slopes 20Determining Stratigraphic Thickness by Orthographic Projection 203 Stereographic Projection 31Objective 31Plotting a Plane 33Plotting a Line 33Plotting the Pole to a Plane 34Line of Intersection of Two Planes 35Angles of Lines within a Plane 36Determining True Dip from Strike and Apparent Dip 37Determining Strike and Dip from Two Apparent Dips 384 Folds and Cross Sections 43Objectives 43Glossary of Fold Terms 43Classification by Shape 45Classification by Orientation 45Fold Classification Based on Dip Isogons 47Outcrop Patterns of Folds 48Cross or Structure Sections of Folded Layers 49The Arc Method 50Down-Plunge Projection 505 Stereographic Analysis of Folded Rocks 67Objectives 67Beta (ß) Diagrams 67Pi (pi) Diagrams 68Pole Plotter 68Determining the Orientation of the Axial Plane Using Fold Trace 69Constructing the Profile of a Fold Exposed in Flat Terrain 69Determining the Orientation of the Axial Plane Without a Fold Trace 70Simple Equal-Area Diagrams of Fold Orientation 71Contour Diagrams 71Determining the Fold Style and Interlimb Angle from Contoured Pi Diagrams 756 Rotations and Determining Original Directions in Folded Rocks 87Objectives 87Rotation of Lines 87The Two-Tilt Problem 89Cones: The Drill-Hole Problem 90Unfolding Folds 937 Foliations, Parasitic Folds, and Superposed Folds 95Objectives 95Foliations 95Parasitic Folds 97Superposed Folds 998 Strain Measurements in Ductile Rocks 107Objectives 107Longitudinal Strain 107Shear Strain 108The Strain Ellipse 108Strain Fields 108The Coaxial Total Strain Ellipse 109Measuring Strain in Deformed Objects 110Strain in Folds 111Deformed Fossils as Strain Indicators 111Mohr Circle for Sheared Fossils 112Mohr Circle for Boudinage 1139 Advanced Strain Measurements 125Objectives 125Fry Method 126Rf/phi Method 12710 Brittle Failure 131Objective 131Quantifying Two-Dimensional Stress 131The Mohr Diagram 133The Mohr Circle of Stress 134Rules for Going Between Mohr Space and Real Space 135The Failure Envelope 135The Importance of Pore Pressure 13811 Analysis of Fracture Systems 147Objectives 147Data Collection 148Rose Diagram 148Length vs Strike Graphs 149Interpreting Joint Strike Diagrams 150Contouring Joint Density 150Accounting for Dip in Joints 15212 Faults 157Objectives 157Measuring Slip 159Rotational (Scissor) Faulting 161Map Patterns of Faults 162Timing of Faults 16313 Dynamic and Kinematic Analysis of Faults 169Objectives 169Dynamic Analysis 169Kinematic Analysis 17414 Structural Synthesis 191Objective 191Structural Synthesis 191Some Suggestions for Writing Style 193Common Errors in Geologic Reports 19315 Deformation Mechanisms in Mylonites 197Objectives 197Deformation Mechanisms 197Fault Rocks 200Kinematic Indicators 202S-C Fabrics 202Asymmetric Porphyroclasts 202Oblique Grain Shapes in Recrystallized Quartz Aggregates 203Antithetic Shears 203Strain and Offset in Shear Zones 204Potential Sources of Error 20516 Construction of Balanced Cross Sections 213Objectives 213Thrust-Belt "Rules" 213Recognizing Ramps and Flats 214Relations Between Folds and Thrusts 215Requirements of a Balanced Cross Section 218Constructing a Restored Cross Section 219Constructing a Balanced Cross Section 22017 Introduction to Plate Tectonics 233Objectives 233Fundamental Principles 233Plate Boundaries 234Triple Junctions 235Focal-Mechanism Solutions ("Beach-Ball" Diagrams) 236Earth Magnetism 240Apparent Polar Wander 24218 Virtual Field Trip 253Objective 253Newfoundland Folds Field Trip 254Ramapo Fault Field Trip 255References 257Further Reading 259Index 265

O autorze

About the AuthorsStephen 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.