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The Western North Atlantic Region THE WESTERN NORTH ATLANTIC REGION The Geology of North America Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/4149319/9780813754642_frontmatter.pdf by guest on 02 October 2021 Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/4149319/9780813754642_frontmatter.pdf by guest on 02 October 2021 The Western North Atlantic Region Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/4149319/9780813754642_frontmatter.pdf by guest on 02 October 2021 Frontispiece 1. Examples of principal lithofacies in the western North Atlantic Ocean basin. All are core samples from the Deep Sea Drilling Project. Each is identified in parentheses below according to cruise leg, site number (with hole number, A., B., etc., if applicable), core number, core-section number, and depth interval in core section (in centimeters). 1. Un-named formation, Blake-Bahama Basin. Upper Callovian to lower Oxfordian dark claystone with coarser radiolarian siltstone lenses, capped at top by lighter pelmicritic limestone that is graded and laminated (76, 534A, 120,1,48-65 cm). These and 63 m of underlying Callovian sedimen- tary rocks at Site 534A represent the oldest strata cored to date in the western North Atlantic basin. 2. Cat Gap Formation, lower continental rise off New Jersey. Upper Oxfordian to lower Kim- meridgian clayey limestone, well laminated to burrowed (11, 105, 37, 5, 82-113 cm). Colors which reflect the oxidation state of iron in the sediment (reddish = oxidized, grayish = reduced) are separated by diffuse boundaries. 3. Blake-Bahama Formation, lower continental rise off New Jersey. Upper Berriasian to lower Valanginian limestone and chalky limestone (11,105,28,1,92-141 cm). Limestone is well laminated to burrowed and locally contains flow structures. Darker layers contain clay and nannofossils, and light layers are principally recrystallized nannofossil calcite. 4. Hatteras Formation, western Bermuda Rise. Upper Hauterivian-Barremian greenish gray, lami- nated to burrowed claystone and laminated, black radiolarian mudstone with pyrite crystals and nodules (43,387,37,4,2-48 cm). Deposition was under low-oxygen (green-gray) to anoxic conditions (black). 5. Plantagenet Formation, central Bermuda Rise. Upper Cretaceous dusky yellow brown and moderate brown zeolitic claystone (43, 386, 38, 4, 37-70 cm). Darker brown bands are zeolite-rich (-60%) compared to lighter brown bands (-30%). Plantagenet clays accumulated at extremely low rates (~ 1-3 m/m.y.) beneath well oxygenated waters in the late Cretaceous basin. 6. Plantagenet Formation, lower continental rise off New Jersey. Upper Cretaceous multicolored silty clay with rare sphalerite and zeolites (11, 105, 9, 2, 108-123 cm). 7. Volcaniclastic breccia, flank of Nashville Seamount (43,382, 25, 2, 110-133 cm). Basalt clasts show variable degrees of alteration and are contained within a matrix of gray-white calcite. Nashville Seamount was the easternmost volcanic edifice formed in the New England Seamount Chain as the North American plate migrated across the New England hotspot in the Late Cretaceous. 8. Volcaniclastic breccia, flank of Vogel Seamount, New England Seamount Chain (43, 385, 23, 2,99-123 cm). Variably altered, rounded to angular basalt clasts in this Upper Cretaceous breccia are set in a matrix of calcite cement. 9. Volcaniclastic turbidites, flank of Nashville Seamount, New England Seamount Chain (43,382, 17, 1, 67-114 cm). These lower Campanian beds are laminated to cross-laminated and consist of volcanogenic clay and silty clay with interbeds of marly nannofossil ooze and zeolitic feldspathic silt. They form the uppermost part of the volcaniclastic apron of Nashville Seamount, above the breccias shown in panel 7. 10. Plantagenet Formation, lower continental rise off New Jersey. Upper Cretaceous or Paleogene silty clay with thin clayey quartz-sand stringers, heavy minerals, and palagonite grains (11, 105, 6, 2, 36-61 cm). Sharp color break in lower part of panel is a photographic artifact. 11. Bermuda Rise Formation, western Bermuda Rise. Lower Eocene radiolarian mudstone, more carbonate rich (<25%) in lower part (43, 387, 22, 3, 116-138 cm). Fine-grained, distal turbidites were episodically deposited in the central western North Atlantic basin at this time; the panel shows the upper part of one turbidite: a thick, homogeneous unit capped by burrow-mottled low-carbonate mud at the top of the turbidite sequence. The mudstones commonly are silicified and contain porcelanitic chert, particularly at the tops and bases of turbidites. 12. Blake Ridge Formation, lower continental rise terrace off New Jersey. The middle Miocene, burrow-mottled, gray-brown hemipelagic mudstone is characteristic of the Blake Ridge Formation (11, 106B, 5, 3,76-88 cm). 13. Blake Ridge Formation, central Bermuda Rise. Middle Eocene burrowed-mottled, marly biosiliceous ooze (top of a turbidite) capped by laminated biosiliceous ooze and biosiliceous mud (base of a turbidite) (43, 386, 17, 3, 76-98 cm). Biosiliceous component is primarily sponge spicules and radiolarians. 14. Great Abaco Member, Blake Ridge Formation, Blake-Bahama Basin. Lower Miocene silty, calcareous, biosiliceous claystone capped by laminated marly chalk forming the base of a turbidite (76, 534A, 14,5,50-65 cm). The Great Abaco Member is characterized by intraclastic chalks and calcareous turbidites deposited within the Blake-Bahama Basin. Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/4149319/9780813754642_frontmatter.pdf by guest on 02 October 2021 Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/4149319/9780813754642_frontmatter.pdf by guest on 02 October 2021 Frontispiece 2. Portion of computer-generated image "Gravity Field of the World's Oceans," derived from SEASAT altimetry by W. F. Haxby. Published by U.S. Navy Office of Naval Research. Cover photo. Portion of computer-generated image, "Relief of the Surface of the Earth," edited by J. R. Heirtzler, Report MGG-2, National Geophysical Data Center. Submarine topography based on DBDB- 5 (Digital Bathymétrie Data Base) of U.S. Naval Oceanographic Office. Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/4149319/9780813754642_frontmatter.pdf by guest on 02 October 2021 The Geology of North America Volume M The Western North Atlantic Region Edited by Peter R. Vogt Naval Research Laboratory Washington, D.C. 20375-5000 and Brian E. Tucholke Woods Hole Oceanographic Institution Woods Hole, Massachusetts 02543 Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/4149319/9780813754642_frontmatter.pdf by guest on 02 October 2021 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: ARCO Exploration Company Phillips Petroleum Company Chevron Corporation Shell Oil Company Cities Service Company Caswell Silver Conoco, Inc. Sohio Petroleum Corporation Diamond Shamrock Exploration Standard Oil Company of Indiana Corporation Sun Exploration and Production Company Exxon Production Research Company Superior Oil Company Getty Oil Company Tenneco Oil Company Gulf Oil Exploration and Production Texaco, Inc. Company Union Oil Company of California Paul V. Hoovler Union Pacific Corporation and Kennecott Minerals Company its operating companies: Kerr McGee Corporation Champlin Petroleum Company Marathon Oil Company Missouri Pacific Railroad Companies Rocky Mountain Energy Company McMoRan Oil and Gas Company Union Pacific Railroad Companies Mobil Oil Corporation Upland Industries Corporation Pennzoil Exploration and Production U.S. Department of Energy Company © 1986 by The Geological Society of America, Inc. Library of Congress Cataloging-in-Publication Data All rights reserved. The Western North Atlantic region. All materials subject to this copyright and included in this volume may be photocopied for the noncommercial (The Geology of North America; v. M) purpose of scientific or educational advancement. Bibliography: p. Includes index. Copyright is not claimed on any material prepared "One of the synthesis volumes of the Decade of North by government employees within the scope of their American Geology Project series"—P. employment. 1. Geology—North Atlantic Ocean. 2. Geophysics— North Atlantic Ocean. 3. Paleoceanography—North Published by the Geological Society of America, Inc. Atlantic Ocean. 4. Mines and mineral Resources— 3300 Penrose Place, P.O. Box 9140, Boulder, Colorado 80301 North Atlantic Ocean. I. Vogt, Peter R. (Peter Richard), 1939- . II. Tucholke, Brian E. Printed in U.S.A. III. Geological Society of America. IV. Decade of North American Geology Project. V. Series. QE71.G48 1986 vol. M 557 s 86-19550 [QE350.2] [551.46'08'0931] ISBN 0-8137-5202-7 Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/4149319/9780813754642_frontmatter.pdf by guest on 02 October 2021 Contents Preface xi Foreword xiii INTRODUCTION 1. Perspectives on the geology of the North Atlantic Ocean 1 Brian E. Tucholke and Peter R. Vogt 2. Imaging the ocean floor: History and state of the art 19 Peter R. Vogt and Brian
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