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MARGINS: A RESEARCH INITIATIVE FOR INTERDISCIPLINARY STUDIES OF PROCESSES ATTENDING LITHOSPHERIC EXTENSION AND CONVERGENCE Proceedings of a Workshop sponsored by the National Research Council Beckman Center, Irvine, California November 20-23, 1988 Continental Margins Committee ocean Studies Board Commission on Physical Sciences, Mathematics, and Resources National Research Council National Academy Press Washington, D.C. 1989
NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee consisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientif ic and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Frank Press is president of the National Academy of Sciences. The National Academy of Engineering was-established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy -of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Robert M. White is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Samuel Thier is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sc, ences in 1916 to associate the broad community of science and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Frank Press and Dr. Robert M. White are chairman and vice chairman, respectively, of the National Research Council. Library of Congress Catalog Card No. 89-64194 International Standard Book Number 0-309-04188-0 Additional copies of this report are available from: National Academy Press 2101 Constitution Avenue, NW Washington, D.C. 20418 SOBS Printed in the United States of America First Pnniing, Feb' y 1990 Second Printing, November 1990
CONTINENTAL MARGINS COMMITTEE Steering Committee C. BARRY RALEIGH, Lamont-Doherty Geological Observatory, Chairman JAMES Ae AUSTIN, JR., University of Texas at Austin MARK BRANDON, Yale University DARREL S. COWAN, University of Washington DANIEL M. DAVIS, State University of New York, Stony Brook SUZANNE M. KAY, Cornell University GREGORY F. MOORE, University of Tuisa JOHN C. MUTTER, Lamont-Doherty Geoff ogical Observatory DAVID A. ROBERTS, Standard Oil Production BRIAN WERNICKE, Harvard University Working_Group Topics and Members Passive Margins Section Chair: John C. Mutter Group 1: Mechanics of Rifting and Associated Magmatism. Work Group Chair: David Roberts. Members: Rick Allmendinger, James A. Austin, Jr., Enrico Bonatti, Roger Buck' Robert Detrick, Philip Cans, Deborah Hutchinson, Jeffrey A. Karson, Kim D. KliLgord, Mark Legg, John C. Mutter, John Nabelek, Bruce R. RosendahI, John G. Scraper, Michael Steckler, Paul Stoffa, Brian P. Wernicke, Robert S. White, and Carolyn Zehnder. Group 2: Rift and Passive Margin Basins: The Sedimentary Record. Work Group Chair: William B.F. Ryan. Members: Daniel Bernoulli' James Coleman, William Galloway, Lubomir Jansa, Susan M. Kidwell, Warren Manspeizer, Gregory Mountain, Donald Swift, Brian Tucholke, and Joel S . Watkins . Group 3: Post-Depositional Processes: External versus Internal Processes in Passive Margin Sediments. Work Group Chair: Lawrence M. Cathies. Members: David Converse, Janet A. Haggerty, Martin P.A. Jackson, A. Conrad Neumann, Charles Paull, Dale S. Sawyer, Roger Scrutton, Elliott Taylor, and Richard von-Herzen. Active Margins Section Chair: Darrel S. Cowan Group I: Mechanics of Plate Motion. Work Group Chair: Darrell S. Cowan. Members: Mark T. Brandon, Bobb Carson, Daniel M. Davis, Bradford Hager, Hiroo Kanamori, Brian T.R. Lewis, · · ~
Wayne Thatcher, Terry Tullis, and Donald Le Turcotte. Group 2: Geologic Evolution of Active Continental Margins. Work Group Chair: David Scholl. Members: Tim Byrne, Steven C. Cande, James W. Hawkins, Daniel E. Karig, David McAcloo, Gregory F e Moore, Thomas Shipley, Brian Taylor, and Roland van Huene. Group 3: Mass and Chemical Transfer. Work Group Chair : James B ~ Gil ~ . Members: Frederick A. Frey, Christopher Hawkesworth, Robert W . Kay, Suzanne M . Kay, and Crul ie Morris. OSB Staff . Mary Hope Katsouros, Senior Staff Director Steven P e Conner, Sea Grant Fellow Maureen A. Hage, Administrative Secretary/Senior Proj eat Assistant 1V
OCEAN STUDIES BOARD *JOHN G. SCLATER Chairman ROBERT De BEARDSLEY (1991), (1991), The University of Texas at Austin, Woods Hole Oceanographic Institution PETER G. BREWER (1990~, Woods Hole Oceanographic Institution *RUSS E. DAVIS (1991), Scripps Institution of Oceanography JOHN EDMOND (1989), Cambridge University College *EDWARD FRIEMAN (1990), Scripps Institution of Oceanography MICHAEL GLANTZ (1990), National Center for Atmospheric Research ARNOLD L. GORDON (1991), Lamont-Doherty Geological Observatory JOHN I. HEDGES (1991), University of Washington EILEEN HOFMANN (1991), Texas A&M University JAMES J. O'BRIEN (1991), Florida State University JOHN A. ORCUTT (1991), Scripps Institution of Oceanography DENNIS POWERS (1990), Johns Hopkins University C. BARRY RALEIGH (1989), Lamont-Doherty Geological Observatory DAVID A. ROSS (1989), Woods Hole Oceanographic Institution MICHAEL P. SISSENWINE (1991), NOAA/Northeastern Fisheries Service JOHN H. STEELE (1989), Woods Hole Oceanographic Institution MARY TYLER (1990), Versar, Inc. Liaison Members *WALTER H e MnNK, Scripps Institution of Oceanography *KARL K. TUREKIAN, Yale-University DONALD F. BOESCH, Louisiana Universities Marine Consortium D. JAMES BASER, JR., Joint Oceanographic Institutions, Inc. Staff Members Mary Hope Katsouros, Senior Staff Officer Edward R. Urban, Sea Grant Fellow Judith Mackaness, Staf f Assistant Maureen A. Hage, Administrative Secretary Mildred L. McGuire, Senior Secretary *NAB Members
COMMISSION ON PHYSICAL SCIENCES, MATHEMATICS, AND RESOURCES NORMAN HACKERMAN, Robert A. Welch Foundation, Chairman ROBERT C. BEARDSLEY, Woods Hole Oceanographic Institution B. CLARK BURCHFIEL, Massachusetts Institute of Technology GEORGE F. CARRIER, Harvard University RALPH J. CICERONE, University of California at Irvine HERBERT D. DOAN, The Dow Chemical Company (retired) PETER S . EAGLESON, Massachusetts Institute of Technology DEAN E . EASTMAN , IBM T . J ~ Watson Research Center MARY E ANNE FOX, University of Texas GERHART FRIEDL]WDER, - - LAWRENCE W. FUN=OUSER, PHILLIP A. GRIFFITHS, Duke University NEAL F. LANE, Rice University CHRISTOPHER F. McKEE, University of California at Berkel ey RICHARD S. NICHOLSON, American Association for the Advancement of Science JACK E. OLIVER JEREMIAH P. Brookhaven National Laboratory Chevron Corporation r ret i red ., Cornell University OSTRIKER, Princeton University Observatory PHILIP A. PAL=R, E. I. Mu Pont de Nemours & Company FRANK L. PARKER, Vanderbilt Univers ity DENIS J . PRAGER, MacArthur Foundation DAVID M. RAUP, University of Chicago ROY E. SCHWITTERS, Superconducting Super Con licler Laboratory LARRY L. STARR, University of Illinois at Urbana-Champaign KARL K . TUREKIAN, Yale University MYRON F. UMAN, Acting Executive Director ROBERT M. SIMON, Acting Associate Executive Director vi
PREFACE The Bevel opment of plate tectonic theory during the 1960s gave earth scientists a new model for describing processes of lithospheric evolution. With plate theory as a basis for setting research directions, our understanding of oceans and continents in the subsequent decade made major advances, many of which revolutionized the way we now look at the Earth. Plate theory provided the essential kinematic context in which to study the evolution of continental margins, but it did not, of course, directly address the mechanics of their construction and deformation. Over the last decade, this limitation has spurred a gradual shift towards the study of physical and chemical processes associated with margins evolution, primarily through the construction and testing of quantitative models. Advances using this approach have affected a variety of research areas. To assess current trends and plan for future research endeavors, a workshop entitled "Continental Margins: Evolution of Passive Continental Margins and Active Marginal Processes" was organized by two boards of the National Research Council: the Ocean Studies Board and the Board on Earth Sciences ~ now the Board on Earth Sciences and Resources ~ ~ The workshop was held November 20-23, 1988, at the Beckman Center of the National Academy of Sciences and Engineering in Trvine, Cal ifornia. The workshop was broad-based and multidisciplinary. Support was provided by the National Science Foundation ~ Divisions of Ocean Sciences and Earth Sciences), the National Oceanic ant] Atmospheric Administration , the Office of Naval Research, the Department of Energy, and the United States Geological Survey . Seventy-two scientists participated; most of them were from the United States, but there were others from Canada, Great Britain, and Switzerland. They represented research groups based in academia, industry, and government, and their backgrounds ranged over a full spectrum: from geology to geophysics and geochemistry; from continental to marine; and from field-oriented to laboratory- and theory-oriented. In planning the workshop, the Continental Margins Committee turned to scientists whose backgrounds represented a broad · ~ V11
spectrum of views on continental margins research. The result was wide-ranging and spirited discussion in all areas. Each participant was assigned to a working group with the understanding and expectation that many individuals would contribute to more than one group e The cross-disciplinary interaction played ~ major role in the success of the workshop and led to an overwhelming agreement that a new, interdisciplinary effort concentrating on a process-oriented approach to margins research would be both timely and feasible C. Barry Raleigh Chairman . · ~ V111 .
CONTENTS PART I: REPORT OF THE CONTINENTAL MARGINS WORKSHOP Executive Summary 1 Introduction Impetus f or the Workshop, 8 Organization and Support of the Workshop r Charges to the Working Groups, lo 2 Results of the Workshop Margin Processes: A New Rationale for Research into Lithospheric Convergence and Divergence, 12 Future Directions for Research on Margin Processes: Requirements for Success, l9 3 Components of a Margins Initiative A New Approach for Margins Research, 24 A Margins Initiative Committee, 25 Planning Workshops, 25 Drafting a Scientific Plan, 25 PART I I: REPORTS OF THE WORKING GROUPS 4 Pass ive Margins: Group 1 Mechanics of Ri fting and Associated Magmatism Preamble, 29 The S inale Most Important Scienti f ic Obj active, 3 3 Needed Studies, 3 5 s Passive Margins: Group 2 Rift anc} Passive Margin Basins--The Sedimentary Record Preamble, 45 Background, 4 6 The Single Most Importance Scientific Obj ective, 48 Needec] Studies, 53 Strategies Requirec] to Achieve the Goals, 59 1X 1 3 8 12 24 27 29 45
6 Passive Margins: Group 3 Divergent Continental Margins--Post-Rifting Internal Processes Summary, 6 1 Background, 62 The Single Most Important Scientific Objective, 64 Needed Studies, 78 Strategy Required to Achieve Goals, 71 Broader Implications, 71 Selected Bibliography, 72 7 Active Margins: Group l Dynamics of Short-Term Defo`-~uation at Active Margins The Single Most Important Scientific Objective, 73 Three Major Areas for Investigation, 73 Needed Studies, 78 8 Active Margins: Group 2 Geologic Evolution of Active Continental Margins The Single Most Important Scientific Objective, 85 Needed Studies, 91 9 Active Margins: Group 3 Mass and Chemical Transfer Introduction, 95 Critical Problems, 97 Needed Studies, 105 10 Supplementary Note on Rock Mechanics Problems at Active Margins PART III: BACKGROUND PAPERS 61 73 85 95 109 113 APPENDIX: List of Participants 277 x