THE GULF OF MEXICO BASIN The Geology of North America The Geology of North America Volume J The Gulf of Mexico Basin Edited by Amos Salvador Department of Geological Sciences The University of Texas at Austin P.O. Box 7909 Austin, Texas 78713-7909 Acknowledgment Publication of this volume, one of the synthesis volumes of The Decade of North American Geology Project series, has been made possible by members and friends of the Geological Society of America, corporations, and government agencies through contributions to the Decade of North American Geology fund of the Geological Society of America Foundation. Following is a list of individuals, corporations, and government agencies giving and/or pledging more than $50,000 in support of the DNAG Project: Amoco Production Company Pennzoil Exploration and ARCO Exploration Company Production Company Chevron Corporation Phillips Petroleum Company Cities Service Oil and Gas Company Shell Oil Company Diamond Shamrock Exploration Caswell Silver Corporation Standard Oil Production Company Exxon Production Research Company Oryx Energy Company (formerly Getty Oil Company Sun Exploration and Production Gulf Oil Exploration and Production Company) Company Superior Oil Company Paul V. Hoovler Tenneco Oil Company Kennecott Minerals Company Texaco,Inc. Kerr McGee Corporation Union Oil Company of California Marathon Oil Company Union Pacific Corporation and Maxus Energy Corporation its operating companies: McMoRan Oil and Gas Company Union Pacific Resources Company Mobil Oil Corporation Union Pacific Railroad Company Occidental Petroleum Corporation Upland Industries Corporation U.S. Department of Energy ® 1991 by The Geological Society of America, Inc. Library of Congress Cataloging-in-Publication Data All rights reserved. The Gulf of Mexico Basin / edited by Amos Salvador. p. cm. Includes bibliographical references and index. All materials subject to this copyright and included ISBN 0-8137-5216-7 in this volume may be photocopied for the noncommercial 1. Geology—Mexico, Gulf of. 2. Marine mineral resources—Mexico, purpose of scientific or educational advancement. Gulf of. I. Salvador, Amos. QE71.G48 1986 vol. J Copyright is not claimed on any material prepared [QE350.22.M48] by government employees within the scope of their 557 s—dc20 employment. [551.46'08'09364] 91-36132 CIP Published by The Geological Society of America, Inc. 3300 Penrose Place, P.O. Box 9140, Boulder, Colorado 80301 Printed in U.S.A. Front Cover: Part of a relief map of North America showing the Gulf of Mexico region, produced by Johann Baptist Homann (1664-1724), who ranked next in greatness to Mercator among German cartographers. The map is from an atlas published in the early 1700s in Nuremberg, Germany. Reproduced courtesy of the Nettie Lee Benson Latin American Collection, University of Texas at Austin. 10 9 8 7 6 5 4 3 21 ii Contents Preface .......................................................................... v Foreword ....................................................................... vii 1. Introduction ................................................................... 1 A. Salvador 2. Physiography and bathymetry .................................................. 13 W. R. Bryant, J, Lugo, C. Cordova, and A. Salvador 3. Structural framework .......................................................... 31 T. E. Ewing 4. The crust under the Gulf of Mexico basin ......................................... 53 D. S. Sawyer, R. T. Buffler, and R. H. Pilger, Jr. 5. Salt tectonics and listric-normal faulting .......................................... 73 T. H. Nelson 6. Igneous activity ............................................................... 91 G. R. Byerly 7. Pre-Triassic ................................................................. 109 R. D. Woods, A. Salvador, and A. E. Miles 8. Triassic-Jurassic ............................................................. 131 A. Salvador 9. Lower Cretaceous ............................................................ 181 E. McFarlan, Jr., and L. S. Menes 10. Upper Cretaceous ............................................................ 205 N. F. Sohl, E. Martinez R., P. Salmeron-Urena, and F. Soto-Jaramillo iii iv Contents 11. Cenozoic .................................................................... 245 W. E. Galloway, D. G. Bebout, W. L. Fisher, J. B. Dunlap, Jr, R. Cabrera-Castro, J. E. Lugo-Rivera, and T. M. Scott 12. Late Quaternary sedimentation ................................................ 325 J. M. Coleman, H. H. Roberts, and W. R. Bryant 13. Seismic stratigraphy of the deep Gulf of Mexico basin and adjacent margins ................................................. 353 R. T. Buffler 14. Origin and development of the Gulf of Mexico basin ............................... 389 A. Salvador 15. Oil and gas resources ......................................................... 445 R. Nehring 16. Mineral resources and geopressured-geothermal energy ............................ 495 S. R. Riggs, S. P. Ellison, Jr, W. L. Fisher, W. E. Galloway, M.L.W. Jackson, and R. A. Morton 17. Ground water ............................................................... 529 J. M. Sharp, Jr., C. W. Kreitler, and J. Lesser 18. Summary; Current knowledge and unanswered questions .......................... 545 A. Salvador Index .......................................................................... 551 Plates (in accompanying slipcase) Plate 1. Bathymetric chart, Gulf of Mexico region W. R. Bryant and J. R. Bryant Plate 2. Principal structural features. Gulf of Mexico basin T. E. Ewing and R. F. Lopez Plate 3. Structure at the base, and subcrop below, Mesozoic marine section, Gulf of Mexico basin A. Salvador Plate 4. Natural resources, Gulf of Mexico basin A. Salvador and R. Nehring Plate 5. Stratigraphic correlation chart, Gulf of Mexico basin A. Salvador and J. M. Quezada Muneton Plate 6. Cross sections of the Gulf of Mexico basin A. Salvador Preface The Geology of North America series has been prepared to mark the Centennial of The Geological Society of America. It represents the cooperative efforts of more than 1,000 individuals from academia, state and federal agencies of many countries, and industry to prepare syntheses that are as current and authoritative as possible about the geology of the North American continent and adjacent oceanic regions. This series is part of the Decade of North American Geology (DNAG) Project, which also includes seven wall maps at a scale of 1:5,000,000 that summarize the geology, tectonics, magnetic and gravity anomaly patterns, regional stress fields, thermal aspects, and seismicity of North America and its surroundings. Together, the synthesis volumes and maps are the first coordinated effort to integrate all available knowledge about the geology and geophysics of a crustal plate on a regional scale. The products of the DNAG Project present the state of knowledge of the geology and geophysics of North America through the 1980s, and they point the way toward work to be done in the decades ahead. A. R. Palmer General Editor for the volumes published by The Geological Society of America J. 0. Wheeler General Editor for the volumes published by the Geological Survey of Canada v Foreword The goal of The Geology of North America series of volumes has been to provide a com- prehensive summary or synthesis of the current geological and geophysical knowledge of the regions or subjects covered by each of the volumes. The volumes are intended not so much for those most familiar with the region or subject, but for a broader audience of earth scientists— geologists and geophysicists from anywhere in the world who want to inform themselves about the geological and geophysical configuration of the North American Plate and its surrounding regions. This volume, covering the Gulf of Mexico basin, was planned with these goals in mind. Assuming that a good number of the readers may not be familiar with the geography of the region, much less with the multitude of structural and stratigraphic terms in common use, efforts were made, with varying degrees of success, to keep geographic and geologic terminol- ogy as simple as possible. Keeping in mind, for instance, that earth scientists unacquainted with the stratigraphy of the Gulf of Mexico basin may be confused when faced with the countless number of group, formation, and member terms used in the area, the stratigraphy of the basin was described whenever possible in terms of internationally recognized chrono- stratigraphic terms. As further assistance to the unfamiliar reader in this respect, those chapters of this volume that describe the stratigraphy of the basin contain simplified stratigraphic cor- relation charts that show the relation of the local lithostratigraphic units discussed in the volume to the global chronostratigraphic scale. A more detailed stratigraphic correlation chart, Plate 5, is also included in the volume. For the same reasons, an effort was also made to show in the figures and plates of the volume all geographic and structural terms used in the text. Another important goal of this volume, of course, was for it to be useful to the hundreds of geologists and geophysicists working in the Gulf of Mexico basin, in both the United States and Mexico. Even though the space limitations have not permitted discussion of all aspects of the geology of the basin in as much detail as the local geoscientists may have wanted, I am hopeful that by having available in one place a much-needed summary of a wide range of geological and geophysical information on the basin, as well as a review of current thinking about its interpretation, they may find this volume a valuable reference. For this purpose, emphasis was placed during the preparation of the volume on including an extensive list of references on the subject of each chapter, particularly recent, significant, and up-to-date references. This will allow readers interested in particular subjects to enlarge their knowledge and satisfy their need for additional information. The lists of references, in fact, may be one of the most valuable contributions of the volume. vii viii Foreword I also see this volume as more than just a valuable reference and a useful summary or synthesis of what is now known about the geology of the Gulf of Mexico basin. I want to think that it will become the foundation, the point of departure for future geological and geophysical studies on the basin. Some such studies have been suggested in the last chapter of the volume, but many others need to be undertaken in the years to come. The field is certainly wide open for more studies, and I am hopeful that the publication of this volume will provide the encouragement for undertaking them. Future studies no longer need to be based on old, obsolete information or on only partial or limited kinds of information. New and better interpretations and concepts about the geologic history of the basin can now be based on the broader and essentially complete, up-to-date geological and geophysical information that has either been compiled in the chapters of this volume or is contained in the numerous references listed in each of them. This volume should make it possible to readily find the sources for the bulk of the geological and geophysical information on the Gulf of Mexico basin. For this volume to serve as a foundation for future geological and geophysical studies, a concerted effort was made to separate, during its preparation, facts from interpretations. Most chapters are primarily descriptive of the physiography, stratigraphy, and present structure of the basin and of its natural resources. Interpretation of this information is mainly addressed in the chapter that discusses the origin and development of the basin. To attain uniformity and consistency was another of my aims in editing this volume. Nearly all maps, those of the large plates as well as those in the text figures, are on a common projection—Transverse Mercator Projection, with 100° west as the central meridian—the projection to be used in all DNAG (Decade of North American Geology) maps. Good uniformity was also achieved in the terminology of structural features and stratigraphic units. This volume could be considered to have made an important contribution if this terminology will become the accepted standard terminology for the Gulf of Mexico basin where it is not uncommon for structural features and stratigraphic units to have a confusing number of different names. More limited success was achieved concerning uniformity in the dating of some stratigraphic units, particularly those for which the evidence of age is poor or contro- versial. The preferences of the authors were respected in these cases. No major conflicts were experienced in coordinating the information and ideas con- tained in the various chapters of the volume, a remarkable and surprising achievement considering the well-known independence of thought of earth scientists. The volume deals with a single basin, a large basin to be sure, but a simple one in both stratigraphy and present structure; and while theories about its origin varied considerably at one time, there has been in the last few years a trend toward closer agreement on the subject. As more and better information has become available, most of the early differences of opinion seem to have been settled. I am not sure, however, if this is good or bad. The preparation of this volume was not expected to answer all questions or solve all problems concerning the geology of the Gulf of Mexico basin. It did not. I am hopeful, however, that it may serve, as expected, to clarify some problems and answer some questions; support some assumptions, hypotheses, and concepts; and contradict or weaken others. Many unsolved questions remain. Questions concerning the orogenic belts rimming the Gulf of Mexico basin—the Sierra Madre Oriental in Mexico, the Ouachita orogenic belt, the Ouachita Mountains and the Central Mississippi deformed belt in the United States—as well as those about the pre-Mesozoic geologic history of the region that would become the Gulf of Mexico basin, for instance, are far from answered. The orogenic belts, fortunately, are dis- cussed in other volumes of The Geology of North America series; the pre-Mesozoic history is treated briefly in two chapters of this volume, but the limited amount of information about Precambrian and Paleozoic rocks in the Gulf of Mexico basin region allowed only broad generalizations and poorly supported speculations. Debate is very much alive on these sub- jects. As discussed in the last chapter of the volume, many others require considerable further study. The completion of a volume like this would not have been possible without the contribu- Foreword ix tions of many individuals and organizations. All, unfortunately, cannot be properly ac- knowledged here. Special recognition is due to the authors of the chapters who devoted so much of their valuable time to make this volume a success. With my thanks to them also go my apologies to those who submitted their contributions promptly, as the delay in completing the volume may make their chapters somewhat outdated. All chapters were read by at least two knowledgeable reviewers. I am most grateful to them for their prompt, valuable, and constructive comments and suggestions; they contributed substantially to the improvement of the volume. Outstanding support was received from academic institutions, government agencies, and industrial organizations. To all of them I express my deep gratitude. The Bureau of Economic Geology of the University of Texas deserves special mention—it contributed authors and information to the preparation of several chapters and provided the drafting of Plates 2 to 6, a major undertaking carried out by Margaret Koenig and John Ames under the able direction of Richard Dillon. Petroleos Mexicanos and the Instituto Mexicano del Petroleo kindly furnished valuable information for the compilation of Plates 2 to 5 and made available a number of their earth scientists for the preparation of several chapters. Arco Oil and Gas Company, Chevron U.S.A., Conoco Inc., Exxon Company U.S.A., Standard Oil Production Company, and Texaco U.S.A. helped defray the cost of the drafting for several chapters of the volume. Richard Platt, Patrice Porter, and Maria Saenz did the drafting. Several individuals also deserve exceptional recognition: William A. Thomas, one of the editors of neighboring Volume F-2 (The Appalachian-Ouachita Orogen in the United States), made available copies of manuscripts and maps of his volume in advance of their publication and helped in the preparation of this volume in many other ways; Thomas M. Scott, of the Florida Geological Survey, provided much-needed information and advice about the geology of a part of the Gulf of Mexico basin with which I was very poorly acquainted. The patience and good humor of "Pete" Palmer will always be remembered gratefully; without his enthusi- astic encouragement and support, the task of completing this volume would have been much more difficult. It was a real pleasure working with him. Last, but far from least, I want to thank Betty Kurtz, who typed and retyped innumerable manuscripts and letters, shared with me the ups and downs of the preparation of the volume, and cheerfully saw me through the long ordeal. Amos Salvador Volume editor August 1991 The Geology of North America Vol. J, The Gulf of Mexico Basin The Geological Society of America, 1991 Chapter 1 Introduction Amos Salvador Department of Geological Sciences, The University of Texas at Austin, P.O. Box 7909, Austin, Texas 78713-7909 THE GULF OF MEXICO—DISCOVERY AND EARLY EXPLORATION By the year 1517, 25 years after Christopher Columbus in the New World had indicated the existence of such a superior discovered the New World, most of the Atlantic coasts of both culture! They were met with fierce hostility by the Indians at North and South America had been sighted and reasonably well Cabo Catoche and by those of other settlements as they sailed surveyed. Most of the islands of the Caribbean had been colon- along the north shore of Yucatan. Hernandez de Cordoba fol- ized by the Spaniards, and northern South America and the lowed the coast as far west as the present town of Champoton, in Caribbean coast of Central America, from Panama to Honduras, the Bay of Campeche, still uncertain as to whether Yucatan was had been explored and mapped. Four years earlier, in 1513, part of an island or not. The hostility of the Indians, who killed or Vasco Nunez de Balboa had reached the Pacific Ocean by cross- wounded all but one of the members of the expedition, and the ing the isthmus of Panama, but the search for a sea route to the consequent difficulty in putting ashore to obtain fresh water, Pacific and to the fabulous kingdoms of the Orient, the original forced a badly wounded Hernandez de Cordoba to return to objective of Columbus' trips, had not yet met with success. The Cuba by way of Florida where the Indians proved no less dan- great Gulf of Mexico—the "Sinus Mexicanus" of many old gerous than those of Yucatan. He died soon after his return, but maps—also remained unknown, and there was considerable con- brought back samples of gold ornaments and news of an ad- fusion concerning which of the discovered lands were islands and vanced and rich civilization, and of a previously unknown large which were parts of the mainland. body of water that could provide the long-sought sea route to the Juan Ponce de Leon, in his search for the legendary fountain Pacific. that would restore youth to old men, had explored in 1513 the It did not take long before another expedition sailed from east coast of the Florida Peninsula as far north as the present Cuba to confirm the discoveries of Hernandez de Cordoba. It was location of St. Augustine, but had only ventured a short distance commanded by Juan de Grijalva and left in four vessels in the north along the west coast. He was convinced that he had discov- spring of 1518. Grijalva first sighted land at the island of Cozumel ered an immense island. Diego Miruelo, in 1516, explored the and from there he coasted the Yucatan Peninsula, then followed east coast of Florida and seems to also have sailed some distance the shore of east-central Mexico as far north as a large headland, along the west coast of the peninsula. But neither Ponce de Leon probably Cabo Rojo, just north of the present town of Tuxpan, nor Miruelo realized they had sailed into the entrance to a vast where strong currents and unfavorable winds made it difficult to gulf or inland sea around whose shores advanced civilizations had continue. flourished for many centuries and which would become a major Juan de Grijalva experienced the same hostility that Her- political and economic center of the New World. nandez de Cordoba had endured before him, but he was better The Gulf of Mexico was discovered in 1517. A three-ship prepared to handle it and succeeded in having some amicable expedition headed by Francisco Hernandez de Cordoba on its communication with the natives. Before reaching the farthest way from Cuba to the island of Guanaja, near the northern coast point in his voyage, he sent Pedro de Alvarado back to Cuba in of Honduras, was blown off course by a violent storm and after one of his caravels, with the gold objects obtained by bartering sailing for three weeks reached land in the northeastern part of with the Indians and the news of his discoveries. Grijalva had the Yucatan Peninsula, near what is now called Cabo Catoche. confirmed the existence of an advanced, powerful and wealthy There the Spaniards were astonished by the sight of a sizable society. He had found, too, that Yucatan was probably not an town with masonry houses and temples, by the advanced cultiva- island but part of the mainland—a spacious country, as evidenced tion of the land, and by the fine garments and gold ornaments by the eternal snows in the high peaks he had seen from afar. A worn by the inhabitants—nothing that had previously been seen passage to the Pacific remained undiscovered. Salvador, A., 1991, Introduction, in Salvador, A., The Gulf of Mexico Basin: Boulder, Colorado, Geological Society of America, The Geology of North America, V.J. 1