Stratigraphy: A Modern Synthesis Andrew D. Miall

Stratigraphy: A Modern Synthesis

123 Andrew D. Miall Department of Geology University of Toronto Toronto, ON Canada

ISBN 978-3-319-24302-3 ISBN 978-3-319-24304-7 (eBook) DOI 10.1007/978-3-319-24304-7

Library of Congress Control Number: 2015952024

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Springer International Publishing AG Switzerland is part of Springer Science+Business Media (www.springer.com) “For Meredith, Henry and Owen” Preface

The stratigraphic record is the major repository of information about the geological history of Earth, a record stretching back for nearly 4 billion years. Stratigraphic studies fill out our planet’s plate-tectonic history with the details of paleogeography, past climates, and the record of evolution, and stratigraphy is at the heart of the effort to find and exploit fossil-fuel resources. The exploration of this history has been underway since James Hutton first established the basic idea of uniformitarianism toward the end of the eighteenth century, and William Smith developed the stratigraphic basis for geological mapping a few decades later. Modern strati- graphic methods are now able to provide insights into past geological events and processes on time scales with unprecedented accuracy and precision, and have added much to our under- standing of global tectonic and climatic processes. But it has taken 200 years and a modern revolution to bring all the necessary developments together to create the modern, dynamic science that this book sets out to describe. It has been a slow revolution, but stratigraphy now consists of a suite of integrated concepts and methods, several of which have considerable predictive and interpretive power. It is argued in Chap. 1 of this book that the new, integrated, dynamic science that stratigraphy has become is now inseparable from what were its component parts, including sedimentology, chronostratigraphy, and the broader aspects of basin analysis. In this chapter, the evolution of this modern science is traced from its nineteenth-century beginnings, including the contri- butions that such special fields as facies analysis, fluid hydraulics, plate tectonics, and the reflection-seismic surveying method have made to its evolution. The following are just some of the major features of the stratigraphy of the early twenty-first century: Sequence stratigraphy has become the standard methodology for docu- mentation, mapping and interpretation, replacing the old descriptive practices of lithostratig- raphy; reflection-seismic methods, including the use of 3-D seismic and the application of seismic geomorphology, have become steadily more advanced tools for subsurface exploration and development; the Geological Time Scale is being standardized with the universal adoption of the system of Global Stratigraphic Sections and Points (GSSPs) and has become much more precise, with the incorporation of several new methods for evaluating deep time. The basic field and subsurface observations on which stratigraphy is based are described in Chap. 2. Facies analysis methods are detailed in Chap. 3, and the recognition of depositional environments by facies methods is described in Chap. 4. Chapter 5 provides a succinct summary of sequence models for siliciclastic and carbonate sediments, and Chap. 6 describes modern mapping methods for use in surface and subsurface studies, including seismic methods. The synthesis of all this material is detailed in Chap. 7, which includes a discussion of the current attempts to standardize sequence-stratigraphic terminology and the Geological Time Scale. Chapter 8, the concluding chapter of the book, focuses on the new understanding we are acquiring about the processes by which the stratigraphic record preserves elapsed geologic time. Refinements in chronostratigraphic methods are revealing the importance of breaks in the sedimentary record and the ubiquity of missing time, and are revealing an important disconnect between sedimentation rates and preservational processes operating at the present

vii viii Preface day versus those we interpret from the rock record. This calls for a significant modification in the way that we apply the traditional principles of uniformitarianism to our reconstructions of geologic history. The new synthesis that is the subject of this book is offered for advanced undergraduate and graduate training and for use by professionals, particularly those engaged in mapping and subsurface exploration and development.

Toronto Andrew D. Miall April 2015 Revision History

My first book, Principles of Sedimentary Basin Analysis, has gone through three editions, published successively in 1984, 1990, and 1999. A year or so ago, I realized that it might be time for a new edition. In reviewing the changes that have taken place in the whole broad field of sedimentary geology since that last edition, it became clear that stratigraphy is the area that has undergone the most significant changes in the last decades, and that is what I decided would most usefully be treated at length in this book. Stratigraphy has undergone a revolution that has brought together multiple developments dealing with different themes and concepts in sedimentary geology and basin analysis. Chapter 1 includes a new section in which I trace the evolution of these many themes, and attempt to show how they have come together during the last few decades (since about 1990). The text of Chaps. 2 and 4 from Principles has been updated and becomes Chaps. 2–4 in the present book. Chapter 3 of Principles, which dealt with dating and correlation, and the formal methods for the definition and naming of units, has been substantially rewritten and incorporates much of the material I wrote for “Sophisticated Stratigraphy,” a review prepared at the invitation of the Geological Society of America (Miall 2013). It has been moved further along in the present book, appearing as Chap. 7, the point being that stratigraphy should now be seen as a science that synthesizes sedimentary geology, and which therefore requires that the subject is best addressed once the work of sedimentological description and interpretation is underway. Chapters 5 and 6 of the present book are those that have undergone the most complete rewriting, to reflect the major changes in the science since the previous edition. Sequence stratigraphy (Chap. 5) has become the standard method for formal description and paleo- geographic interpretation, and mapping methods (Chap. 6) are now dominated, at least in the petroleum industry, by the techniques of the reflection-seismic method, including 3-D seismic and the interpretive methods of seismic geomorphology. The book culminates with Chap. 8, which is intended primarily as a review of current research into the nature of deep time as preserved in the sedimentary record. It is partly based on two research publications (Miall 2014b; Miall 2015) that focus on modern data dealing with sedimentation and accommodation rates, and the implications of these data for strati- graphic interpretation. The chapter concludes with a review of the current advanced research into cyclostratigraphy and astrochronology.

References

Miall, A. D., 2013, Sophisticated stratigraphy, in Bickford, M. E., ed., The web of geological sciences: Advances, impacts and interactions: Geological Society of America Special Paper 500, p. 169-190. Miall, A. D., 2014b, The emptiness of the stratigraphic record: A preliminary evaluation of missing time in the Mesaverde Group, Book Cliffs, Utah: Journal of Sedimentary Research, v. 84, p. 457-469. Miall, A. D., 2015, Updating uniformitarianism: stratigraphy as just a set of “frozen accidents”, in Smith, D. G., Bailey, R., J., Burgess, P., and Fraser, A., eds., Strata and time: Geological Society, London, Special Publication 404, p. 11-36.

ix Acknowledgments

Colleagues who assisted with the earlier editions of Principles by critically reading parts or all of the manuscript include Tony Tankard, Andy Baillie, Guy Plint, and Ray Ingersoll. I am eternally grateful for their wise advice, and if they choose to do so they will find significant portions of the book that describe basic methods, such as the foundations of facies analysis methods, largely unchanged in this book. Reviewers for the journal articles from which material in Chaps. 7 and 8 was drawn included Felix Gradstein, Ashton Embry, Bruce Wilkinson, Tony Hallam, Alan Smith, Brian Pratt, Gerald Bryant, John Holbrook, Chris Paola, Pete Sadler, Robin Bailey, Dave Smith, John Howell, and Torbörn Törnqvist. The historical section in Chap. 1 was reviewed by Bill Fisher, Ron Steel, Bob Dalrymple, and Martin Gibling. Chapters 5–7 were critically read by David Morrow. I extend my thanks to all these individuals. Any remaining errors or omissions remain my responsibility. Once again I must acknowledge the enthusiastic support and encouragement of my wife, Charlene Miall. Her insights into the scientific method and the sociology of science have been particularly invaluable. My children, Chris (partner Natalie) and Sarah (partner Brad) have consistently been supportive.

xi Contents

1 The Scope of Modern Stratigraphy ...... 1 1.1 The Importance of Stratigraphy ...... 1 1.2 The Evolution of “Sophisticated Stratigraphy” ...... 2 1.2.1 Beginnings (Nineteenth Century) ...... 3 1.2.2 Cyclic Sedimentation (1932–1968)...... 3 1.2.3 Basin Analysis and the Big Picture (1948–1977) ...... 4 1.2.4 The Meaning of “Facies” (1949–1973) ...... 5 1.2.5 Fluid Hydraulics and Sedimentary Structures (1953–1976) . . . . . 6 1.2.6 Early Studies of Modern Environments (1954–1972) ...... 7 1.2.7 Facies Model Concept (1959–2010) ...... 7 1.2.8 The Impact of the Plate-Tectonics Revolution on Basin Studies (1959–1988) ...... 9 1.2.9 Unconformities and the Issue of Time in Stratigraphy (1909–1970) ...... 11 1.2.10 Sequences and Seismic Stratigraphy (1963–1977)...... 13 1.2.11 Architectural Elements: Sedimentology in Two and Three Dimensions (1983–1990) ...... 14 1.2.12 Sequence Stratigraphy (1986–1990) ...... 14 1.2.13 Reconciling Facies Models with Sequence Stratigraphy (1990). . . 15 1.2.14 The Full Flowering of Modern Sequence-Stratigraphic Methods ...... 16 1.2.15 Stratigraphy: The Modern Synthesis ...... 17 1.3 Time in Stratigraphy...... 17 1.4 Types of Project and Data Problems ...... 18 1.4.1 Regional Surface Stratigraphic Mapping Project ...... 18 1.4.2 Local Stratigraphic-Sedimentologic Mapping Project...... 19 1.4.3 Regional Subsurface Mapping Project ...... 20 1.4.4 Local Subsurface Mapping Project ...... 23 1.5 Summary of Research and Reporting Procedures ...... 24 References ...... 26

2 The Stratigraphic-Sedimentologic Data Base ...... 33 2.1 Introduction ...... 33 2.2 Describing Surface Stratigraphic Sections ...... 33 2.2.1 Methods of Measuring and Recording the Data ...... 34 2.2.2 Types of Field Observation ...... 36 2.2.3 Sampling Plan ...... 55 2.2.4 Plotting the Section ...... 58 2.3 Describing Subsurface Stratigraphic Sections ...... 60 2.3.1 Methods of Measuring and Recording the Data ...... 60 2.3.2 Types of Cutting and Core Observation ...... 62

xiii xiv Contents

2.3.3 Sampling Plan ...... 64 2.3.4 Plotting the Section ...... 64 2.4 Petrophysical Logs ...... 65 2.4.1 Gamma Ray Log (GR) ...... 66 2.4.2 Spontaneous Potential Log (SP) ...... 67 2.4.3 Resistivity Logs ...... 68 2.4.4 Sonic Log ...... 69 2.4.5 Formation Density Log ...... 70 2.4.6 Neutron Log ...... 70 2.4.7 Crossplots ...... 71 2.4.8 Integrating Cores and Wireline Logs...... 74 References ...... 74

3 Facies Analysis...... 77 3.1 Introduction ...... 77 3.2 The Meaning of Facies ...... 77 3.3 Recognition and Definition of Facies Types...... 79 3.3.1 Philosophy and Methods ...... 79 3.3.2 Field Examples of Facies Schemes ...... 80 3.3.3 Establishing a Facies Scheme...... 82 3.3.4 Facies Architecture ...... 84 3.4 Facies Associations and Models ...... 87 3.4.1 The Association and Ordering of Facies ...... 87 3.4.2 The Theory of Facies Models ...... 89 3.4.3 The Present as the Key to the Past, and Vice Versa ...... 91 3.4.4 To Classify and Codify, or Not? ...... 94 3.4.5 Facies Analysis and Sequence Stratigraphy ...... 96 3.5 Review of Environmental Criteria...... 96 3.5.1 Grain Size and Texture ...... 97 3.5.2 Petrology...... 99 3.5.3 Bedding ...... 103 3.5.4 Hydrodynamic Sedimentary Structures ...... 104 3.5.5 Sediment Gravity Flows ...... 115 3.5.6 Sedimentary Structures Produced by Hydrodynamic Erosion of the Bed ...... 122 3.5.7 Liquefaction, Load and Fluid Loss Structures...... 123 3.5.8 Paleoecology of Body Fossils ...... 123 3.5.9 Ichnology ...... 132 3.5.10 Vertical Profiles ...... 134 3.5.11 Architectural Elements and Bounding Surfaces...... 139 3.6 Conclusions and Scale Considerations...... 151 References ...... 151

4 Facies Models ...... 161 4.1 Introduction ...... 161 4.2 Clastic Environments ...... 162 4.2.1 Fluvial Environments ...... 162 4.2.2 Eolian Environments...... 166 4.2.3 Lacustrine Environments ...... 168 4.2.4 Glacial Environments ...... 169 4.2.5 Coastal Wave- and Tide-Dominated Environments ...... 172 4.2.6 Deltas ...... 176 Contents xv

4.2.7 Estuaries ...... 182 4.2.8 Continental Shelf Environment...... 183 4.2.9 Continental Slope and Deep Basin Environment...... 185 4.3 Carbonate Environments ...... 190 4.3.1 Conditions of Carbonate Sedimentation...... 190 4.3.2 Platforms and Reefs ...... 196 4.3.3 Tidal Sedimentation ...... 201 4.3.4 Carbonate Slopes ...... 203 4.4 Evaporites ...... 206 References ...... 210

5 Sequence Stratigraphy ...... 215 5.1 Introduction ...... 215 5.2 Elements of the Model ...... 216 5.2.1 Accommodation and Supply ...... 217 5.2.2 Stratigraphic Architecture ...... 217 5.2.3 Depositional Systems and Systems Tracts ...... 224 5.3 Sequence Models in Clastic and Carbonate Settings ...... 225 5.3.1 Marine Clastic Depositional Systems and Systems Tracts ...... 225 5.3.2 Nonmarine Depositional Systems ...... 233 5.3.3 Carbonate Depositional Systems...... 237 5.4 Conclusions...... 241 References ...... 241

6 Basin Mapping Methods...... 245 6.1 Introduction ...... 245 6.2 Stratigraphic Mapping with Petrophysical Logs ...... 246 6.2.1 Log Shape and Electrofacies ...... 246 6.2.2 Examples of Stratigraphic Reconstructions...... 249 6.2.3 Problems and Solutions...... 251 6.3 Seismic Stratigraphy ...... 254 6.3.1 The Nature of the Seismic Record ...... 255 6.3.2 Constructing Regional Stratigraphies...... 263 6.3.3 Seismic Facies ...... 268 6.3.4 Seismic Geomorphology ...... 272 6.4 Directional Drilling and Geosteering ...... 276 6.5 Older Methods: Isopleth Contouring ...... 278 6.6 Mapping on the Basis of Detrital Composition...... 280 6.6.1 Clastic Petrofacies ...... 280 6.6.2 Provenance Studies Using Detrital Zircons ...... 288 6.6.3 Chemostratigraphy ...... 290 6.7 Paleocurrent Analysis ...... 292 6.7.1 Introduction ...... 292 6.7.2 Types of Paleocurrent Indicators ...... 293 6.7.3 Data Collection and Processing ...... 297 6.7.4 The Bedform Hierarchy...... 299 6.7.5 Environment and Paleoslope Interpretations ...... 300 References ...... 305

7 Stratigraphy: The Modern Synthesis...... 311 7.1 Introduction ...... 311 7.2 Types of Stratigraphic Unit ...... 313 7.3 The Six Steps Involved in Dating and Correlation ...... 315 xvi Contents

7.4 Lithostratigraphy ...... 316 7.4.1 Types of Lithostratigraphic Units and Their Definition ...... 317 7.4.2 The Names of Lithostratigraphic Units ...... 319 7.5 Biostratigraphy...... 320 7.5.1 The Nature of the Biostratigraphic Record...... 320 7.5.2 Biochronology: Zones and Datums ...... 326 7.5.3 Diachroneity of the Biostratigraphic Record...... 329 7.5.4 Quantitative Methods in Biochronology ...... 331 7.6 Unconformity-Bounded Units...... 334 7.7 The Development of Formal Definitions for Sequence Stratigraphy...... 335 7.8 Chronostratigraphy and Geochronometry ...... 343 7.8.1 The Emergence of Modern Methods ...... 343 7.8.2 Determining the Numerical (“Absolute”) Age of a Stratigraphic Horizon ...... 345 7.8.3 Stages and Boundaries ...... 351 7.8.4 Event Stratigraphy ...... 355 7.8.5 Absolute Ages: Their Accuracy and Precision ...... 355 7.8.6 The Current State of the Global Stratigraphic Sections and Points (GSSP) Concept, and Standardization of the Chronostratigraphic Scale...... 357 7.8.7 Cyclostratigraphy and Astrochronology ...... 359 References ...... 364

8 The Future of Time ...... 371 8.1 Introduction ...... 371 8.2 Where We Are Now and How We Got Here ...... 372 8.3 A Natural Hierarchy of Sedimentary Processes...... 375 8.4 Sedimentation Rates ...... 378 8.5 The Fractal-Like Character of Sedimentary Accumulation ...... 382 8.6 Apparent Anomalies of High Sedimentation Rate Versus Slow Rate of Accommodation Generation ...... 384 8.7 Accommodation and Preservation...... 385 8.7.1 Preservation at a Scale of Seconds to Months ...... 387 8.7.2 Preservation at a Scale of Years to Thousands of Years ...... 387 8.7.3 Preservation at the Scale of Tens of Thousands to Hundreds of Thousands of Years ...... 388 8.7.4 Preservation at the Scale of Millions of Years ...... 389 8.8 Implications of Missing Time for Modern Stratigraphic Methods ...... 390 8.8.1 Sequence Stratigraphy...... 390 8.8.2 Implications for Stratigraphic Continuity, the Concept of Correlation and the Principal of the GSSP ...... 390 8.8.3 Discussion...... 391 8.9 An Example of the Evaluation of Missing Time: The Mesaverde Group of the Book Cliffs, Utah ...... 392 8.9.1 Chronostratigraphy of the Mesaverde Group ...... 393 8.9.2 Chronostratigraphy of the Spring Canyon and Aberdeen Members ...... 396 8.9.3 The Representation of Time in a Coastal Clastic Succession . . . . 398 8.9.4 Sequence Stratigraphy of the Nonmarine Facies of the Blackhawk Formation and Castlegate Sandstone ...... 399 8.9.5 The Representation of Time in a Fluvial Succession ...... 401 8.9.6 Conclusions...... 403 Contents xvii

8.10 The Future of Conventional Chronostratigraphy ...... 404 8.10.1 Current Examples of Outstanding Work ...... 404 8.10.2 The Use of Wheeler Diagrams ...... 410 8.10.3 Improving Accuracy and Precision ...... 413 8.11 High-Resolution Event Stratigraphy, Cyclostratigraphy and Astrochronology...... 416 8.12 Conclusions...... 424 References ...... 426

Author Index ...... 435

Subject Index ...... 443