Processes in Structural Geology and Tectonics


Contents


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Preface

 

1. GEOLOGIC STRUCTURES AND DEFORMATION REGIMES

INTRODUCTION

CLASSIFICATION OF GEOLOGIC STRUCTURES

SEDIMENTARY STRUCTURES -The Use of Bedding in Structural Analysis --Graded Beds and Cross Beds --Surface Markings --Disrupted Bedding -Conformable and Unconformable Contacts -Compaction and Diagenetic Structures -Penecontemporaneous Structures

SALT STRUCTURES Why Halokinesis? -Geometry of Salt Structures and Associated Processes -Other Gravity-Driven Structures -Importance of Salt Structures

IGNEOUS STRUCTURES -Structures Associated with Sheet Intrusions -Structures Associated with Plutons -Structures Associated with Volcanic Extrusion -Cooling Fractures

IMPACT STRUCTURES

DEFORMATION STRUCTURES -Structural Analysis and Scales of Observation -Guidelines for Structural Analysis -Deformation Regimes -Plate Tectonics

 

2. FORCE AND STRESS

INTRODUCTION -Mechanics -Units and Fundamental Quantities -Force

STRESS -2D Stress: Normal Stress and Shear Stress -3d Stress: Principal Planes and Principal Stresses -The Components of 3D Stress -The Stress Ellipsoid

DERIVING KEY STRESS RELATIONSHIPS

MOHR DIAGRAM FOR STRESS -Constructing the Mohr Diagram

STRESS STATES -Common Stress States in Mohr Space

ISOTROPIC STRESS AND NON-ISOTROPIC STRESS

METHODS OF STRESS MEASUREMENT -Present-Day Stress -Global Stress Patterns -Paleostress

 

3. THE FRICTIONAL REGIME

INTRODUCTION -Brittle Deformation -Categories of Brittle Deformation

PROCESSES OF BRITTLE DEFORMATION -An Atomistic View

TENSILE CRACKING -Elasticity -Stress Concentration

AXIAL EXPERIMENTS -Modes of Crack-Surface Displacement

FORMATION OF SHEAR FRACTURES -Shear Failure Criteria and Failure Envelopes

STRESS AND FAULT TYPES: ANDERSON’S THEORY
FRICTIONAL SLIDING -Frictional Sliding Criteria -Will New Fractures Form or Will Existing Fractures Slide?

LIMITING STRESSES FOR SLIDING ROLE OF FLUIDS -Effect of Pore Pressure on Failure

 

4. JOINTS AND VEINS

INTRODUCTION

SURFACE FEATURES OF JOINTS -Plumose Structure -Why Does Plumose Structure Form?

JOINT ARRAYS -Joint Sets and Joint Systems -Cross-Cutting Relations between Joints -Joint Spacing -Joint spacing and bed thickness -Joint spacing and lithology -Joint spacing and tensile strength -Joint spacing and the magnitude of strain

ORIGIN AND INTERPRETATION OF JOINTS -Related to Uplift and Unroofing -Sheeting (or Exfoliation) Joints -Hydraulic Fracturing

JOINT TERMINATIONS VEINS AND VEIN ARRAYS -Formation of Vein Arrays -Blocky and Fibrous Vein Fill -Interpretation of Fibrous Veins

LINEAMENTS

5. FAULTS

INTRODUCTION FAULT GEOMETRIES AND DISPLACEMENT -Basic Vocabulary

FAULT SYSTEMS -Geometric Classification of Fault Arrays -Normal Fault Systems -Reverse Fault Systems -Strike-Slip Fault Systems -Inversion of Fault Systems

FAULT BENDS -Dip-Slip Faults -Strike-Slip Faults

SUBSIDIARY FAULTS FAULT DIMENSIONS AND TERMINATIONS -Fault Terminations -Fault Dimensions and Self-Similarity

FAULT SURFACES -Slickensides and Slip Lineations

FAULT ROCKS -Classification of Fault Rocks Fault Character with Depth

FAULT ROCKS: MYLONITES -Types of Mylonites

MECHANICS OF FAULTS -The Thrust Paradox -Thrust Wedges

FAULTS AND SOCIETY -Faulting and Resources -Faulting and Earthquakes

 

6. DEFORMATION AND STRAIN

INTRODUCTION

DEFORMATION AND STRAIN

HOMOGENEOUS STRAIN AND STRAIN ELLIPSE

STRAIN PATH

COAXIAL AND NON-COAXIAL STRAIN

SUPERIMPOSED STRAIN

STRAIN QUANTITIES -Longitudinal Strain -Volumetric Strain -Angular Strain -Other Strain Quantities -Natural Strain
3D STRAIN STATES
REPRESENTATION OF STRAIN -Orientation -Shape and Intensity -The Role of Volume Change

FINITE STRAIN MEASUREMENT -Initially Spherical Objects -Variably-shaped Objects --Center-to-Center Method --Rf /φ Method -Angular and Length Changes --Angular Changes --Length Changes

LESSONS FROM STRAIN ANALYSIS -Patterns in Strain Quantities -What Do We Measure?

 

7. THE PLASTIC REGIME

INTRODUCTION

VISCOSITY -Strain Rate

CRYSTAL DEFECTS -Point Defects -Line Defects (or Dislocations)

CRYSTAL PLASTICITY DISLOCATION CREEP -Dislocation Glide -Cross-Slip and Climb -Strain and Dislocations

WHERE DO DISLOCATIONS COME FROM?

DEFORMATION MICROSTRUCTURES -Mechanical Twinning (Low-T Plasticity) -Recovery (Low- to Medium T Plasticity) -Recrystallization (Medium-T Plasticity) --Mechanisms of Recrystallization --Stress and Recrystallization

DIFFUSIONAL MASS TRANSFER -Grain-Boundary and Volume Diffusion -Pressure Solution -Superplasticity

DEFORMATION MECHANISM MAPS -Applications and Limits

CONFUSING TERMINOLOGY? -Deformation Behaviors, Mechanisms and Regimes -Brittle and Ductile Behavior

 

8. FOLDS

INTRODUCTION

ANATOMY OF A FOLD -Fold Facing: Antiform, Synform, and Anticline, Syncline

FOLD CLASSIFICATION -Fold Orientation -Fold Shape in Profile

FOLD SYSTEMS -The Enveloping Surface -Fold Symmetry and Fold Vergence

A FEW SPECIAL FOLD GEOMETRIES MECHANICS OF FOLDING -Passive Folding and Active Folding -Buckle Folds -Folded Multi-layers

KINEMATICS OF FOLDING -Flexural Slip/Flow Folding -Neutral-surface Folding -Fold Shape Modification -Example Scenarios

FAULT-RELATED FOLD GEOMETRIES -Fault-bend Folds -Fault-propagation Folds --Detachment Folds

SUPERPOSED FOLDING -Principle of Fold Superposition -Fold Interference Patterns -Elements of Fold Style -Fold Transposition --Sheath Folds -A Final Note

 

9. FABRICS AND FABRIC ELEMENTS

INTRODUCTION

FABRIC TERMINOLOGY

FOLIATIONS -Cleavage --Disjunctive Cleavage --Pencil Cleavage --Slaty Cleavage --Phyllitic Cleavage --Cleavage Refraction --Crenulation Cleavage --Synthesis: Bedding-Cleavage Relationships -Schistosity -Gneissosity
MYLONITES -Mylonitic Foliations -Shear-Sense Indicators --Geometry and Orientation --Grain-Tail Complexes --Fractured Grains and Mica Fish --Composite Foliations: C-S and C-C' Structures -Summary of Shear-Sense Indicators

FOLIATION KINEMATICS AND METAMORPHISM

FOLIATIONS AND STRAIN -Cleavage and Strain -Mylonitic Foliations and Strain --Rotated Grains --Foliation Orientation

LINEATIONS -Form Lineations -Surface Lineations -Mineral Lineations -Interpretation of Lineations

 

10. THE LITHOSPHERE

INTRODUCTION

ROCK CREEP CURVE

LINEAR RHEOLOGIES -Visco-elastic Behavior -Elastico-viscous Behavior -General Linear Behavior

DEFORMATION ENVIRONMENTS -Deformation Apparatus -Confining Pressure -Temperature -Pore-Fluid Pressure -Strain Rate Strain-dependent Behavior -Competency and Strength -Synthesis: From Laboratory to Nature

A MICROSTRUCTURAL VIEW OF LABORATORY BEHAVIOR

NON-LINEAR RHEOLOGY

EARTH’S RHEOLOGIC LAYERING -Strength Profiles -The Lithosphere -The Asthenosphere

 

11. PLATE TECTONICS

INTRODUCTION

EARTH’S INTERNAL LAYERS -Seismic Layering

THE CRUST -Oceanic Crust -Continental Crust -Age of the Crust -The Moho

THE MANTLE -Subdivision of the Mantle -Mantle Plumes

THE CORE

THE TENETS OF PLATE TECTONICS -Insights from Earthquakes

KINEMATICS OF PLATE TECTONICS -Absolute Plate Velocities -Relative Plate Velocities -Triple Junctions

MECHANICS OF PLATE TECTONICS -Plate-driving Forces

PLATE TECTONIC CYCLES -Wilson Cycle -Supercontinent Cycle

 

12. EXTENSIONAL TECTONICS

INTRODUCTION

TECTONICS OF OCEAN RIDGES

CROSS-SECTIONAL STRUCTURE OF A RIFT -Normal Fault Systems -Examples of Rift Structure in Cross Section -Rift Topography and Rift-Margin Uplifts -Rock Assemblages in Rifts -Rift Accommodation Zones

KINEMATICS OF RIFTING -Cordilleran Metamorphic Core Complexes -Stretching and Subsidence

RIFT EVOLUTION

PASSIVE MARGINS

CAUSES OF RIFTING

 

13. CONTRACTIONAL TECTONICS

INTRODUCTION

CONVERGENT PLATE MARGINS -The Downgoing Slab -The Trench -The Accretionary Wedge -The Forearc Basin and the Volcanic Arc -The Backarc Region -Plate Coupling at Convergent Margins

COLLISIONAL TECTONICS -Stage 1: Pre-collision and Initial Interaction -Stage 2: Abortive Subduction and Suturing -Stage 3: Crustal Thickening and Extensional Collapse

COLLISIONAL OROGENY -Fold-Thrust Belts --Settings of Fold-Thrust Belts --Generalized Cross-section of a Fold-Thrust Belt -Kinematics of Thrust Systems -Insights from Modeling

RELATED PROCESSES OF COLLISIONAL TECTONICS -Extrusion Tectonics -Plateau Uplift -Accretionary Tectonics

OROGENIC ARCHITECTURE -Curved Orogens (Oroclines) -Speculation on Orogenic Styles

 

14. WRENCH TECTONICS

INTRODUCTION

CLASSES OF STRIKE-SLIP FAULTS -Transfer Faults -Transcurrent Faults

STRIKE-SLIP SYSTEMS -Distributed Deformation in Strike-Slip Zones -Transpression and Transtension -Restraining and Releasing Bends -Strike-Slip Duplexes -Understanding the Complexity of Strike-Slip Zones

SETTINGS OF CONTINENTAL STRIKE-SLIP ZONES -Continental Transfer Faults -Continental Transcurrent Faults -Settings of Oceanic Strike-Slip Zones -Oceanic Transform Faults -Oceanic Fracture Zones

 

15. A GLOBAL VIEW AND REGIONAL ESSAYS

INTRODUCTION

GLOBAL DEFORMATION PATTERNS

WHAT CAN WE LEARN FROM REGIONAL PERSPECTIVES? -Orogenic Architecture

SOME SPECULATION ON OROGENIC STYLES

REGIONAL ESSAYS:

THE TECTONIC EVOLUTION OF THE EUROPEAN ALPS AND FORELANDS - Stefan Schmid

THE TIBETAN PLATEAU AND SURROUNDING REGIONS - Leigh Royden and Clark Burchfiel

TECTONICS OF THE ALTAIDS: AN EXAMPLE OF A TURKIC-TYPE OROGEN - Cêlal Sengör and Boris Natal’in

THE TASMAN OROGENIC BELT, EASTERN AUSTRALIA: AN EXAMPLE OF PALEOZOIC TECTONIC ACCRETION - David Gray and David Foster

THE NORTH AMERICAN CORDILLERA - Elizabeth Miller

THE CENTRAL ANDES: A NATURAL LABORATORY FOR NONCOLLISIONAL MOUNTAIN BUILDING - Richard Allmendinger and Teresa Jordan

THE APPALACHIAN OROGEN - James Hibbard

THE CALEDONIDES - Kevin Pickering and Alan Smith

TECTONIC GENEALOGY OF NORTH AMERICA - Paul Hoffman

PHANEROZOIC TECTONICS OF THE UNITED STATES MIDCONTINENT - Stephen Marshak and Ben van der Pluijm

CLOSING REMARKS

THE GEOLOGIC TIMESCALE

ADDITIONAL READING


v1.2; last update:

11-May-2017

 


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