Sedimentary Geology Third Edition

Book Preface

To the Instructor

OVER THE PAST THREE DECADES, WE have introduced many talented undergraduate students to sedimentary geology: in the classroom, in the laboratory, and in the field. The first and second editions of this book were a direct outgrowth of our earlier experiences, and this third edition builds on the strong success of those earlier editions. This text is written especially for undergraduates and is designed specifically for use in a first course in both sedimentary rocks and stratigraphy. We emphasize general principles that students need to master. We intentionally avoid overwhelming students with details, exceptions, or overly specialized examples. Coverage is deliberately weighted in favor of the varieties of sedimentary rocks such as conglomerate, sandstone, mudrock, limestone, and dolostone that make up 99% of the sedimentary rock column. There is a general summary of aqueous geochemistry because a clear understanding of weathering and chemical sedimentation requires it. Similarly, principles of fluid mechanics are covered so that sedimentary structures,
sediment entrainment, and sediment deposition can be adequately understood. Not every detail and nuance of the stratigraphic code is discussed, but a reading of the text will provide students with a good grasp of the relative strengths and weaknesses of various methods of dating and correlation.

We believe that this new edition is a significant improvement over the first and second editions. Those editions enjoyed remarkable success, perhaps because they so fortunately and correctly targeted the market. W hy is this edition better? First of all, a number of users kindly sent us various suggestions about what needed improvement, culling, or expansion. The occasional imprecision was eliminated. We expanded coverage in some areas, such as petroleum geology and chemostratigraphy. We tried to do a better job of understanding and interpreting the sedimentary rock record in the context of an Earth that has evolved through time.

Sedimentary Geology assumes only a single-course background in introductory geology. Additional exposure to historical geology, mineralogy, and petrology is helpful but not crucial. We review or introduce relevant concepts from these fields, as well as from physics, chemistry, and statistics. The level of detail reflects our experience with undergraduate readers and the preferences of instructors. For example, there is little detailed discussion of how rock and mineral components can be discriminated optically. This would require too much space and time, and is probably more adequately presented in published manuals selected by the individual instructor. We recognize that most faculty prefer to design their own laboratories and field trips in order to best capitalize on their own local geology and their personal passions and expertise. We also have not covered to any substantial degree topics like well-logging and subsurface analysis. Undergraduates can better acquire these specialized skills on the job, especially if their understanding of sedimentary geology rests on a strong solid base.

The nucleus for the book is Prothero’s 1990 textbook Interpreting the Stratigraphic Record. Most of the chapters from that book were substantially modified, updated, and shortened. Schwab added new chapters that emphasized the sedimentary rock record expressly for a comprehensive volume that wouldcover both stratigraphy and sedimentary rocks. We have worked together harmoniously and diligently in order to blend our writing sty les. Style, approach, and pedagogy are, we hope, cohesive and uniform. This third edition of Sedimentary Geology builds on the strengths of the first and second: it is intentionally balanced, y et current. Any success earned by this text deservedly belongs to the many bright, well-motivated students who over the y ears were never shy about letting us know what works and what doesn’t. Finally, we hope this text convey s to the students who read, and we hope, enjoy, just how fascinating the world of sedimentary rocks can be.