Topography, Rocks, Structure, Water, Life, and Sediments

WESTERN NORTH ATLANTIC OCEAN: Topography, Rocks, Structure, Water, Life, and Sediments

Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/3839682/9781629812212_frontmatter.pdf by guest on 28 September 2021 WESTERN NORTH ATLANTIC OCEAN: Topography, Rocks, Structure, Water, Life, and Sediments

Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/3839682/9781629812212_frontmatter.pdf by guest on 28 September 2021 Published with financial aid from the DeGolyer Memorial Fund of the AAPG Foundation.

Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/3839682/9781629812212_frontmatter.pdf by guest on 28 September 2021 Memoir 17 WESTERN NORTH ATLANTIC OCEAN: Topography, Rocks, Structure, Water, Life, and Sediments

By K. O. EMERY

and ELAZAR UCHUPI

Published by The American Association of Petroleum Geologists Tulsa, Oklahoma, U.S.A., 1972

THE AMERICAN ASSOCIATION OF PETROLEUM GEOLOGISTS

Published December 1972 Library of Congress Catalogue Card No. 72-89134

COMPOSED, PRINTED, AND BOUND BY THE COLLEGIATE PRESS GEORGE BANTA COMPANY, INC. MENASHA, WISCONSIN 54952

Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/3839682/9781629812212_frontmatter.pdf by guest on 28 September 2021 To our colleagues at Woods Hole, particularly to the Pioneers of Oceanography: Henry Bigelow, Columbus Iselin, Alfred Redjield, and Henry Stetson

Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/3839682/9781629812212_frontmatter.pdf by guest on 28 September 2021 Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/3839682/9781629812212_frontmatter.pdf by guest on 28 September 2021 Great Sun, Who pass on high yet watch all things below, I see the sun-drenched cap of the great castle-wrecker: lePs kick and scuff it around to see where it will take us! Learn, lads, that Time has cycles and that Fate has wheels and that the mind of man sits high and twirls them around; come quick, lefs spin the world about and send it tumbling! Prologue The Odyssey—A Modern Sequel Nikos Kazantzakis

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Preface xi Continental Rises 74 General Shapes—Deep-Sea Channels— Exploration 1 Effects of Bottom Currents—"Lower Continental Rise" Hills Physiography 6 Abyssal Plains 80 Abyssal Hills 83 Historical Development 6 Mid-Atlantic Ridge 84 General Outline 7 Laurentian Upland, Central Low• Rocks 86 lands, and Interior Highlands 8 Appalachian Highlands 10 Sources of Samples and Information 86 New England-Canadian Maritime Basement Rocks 87 Province 11 Mesozoic Sedimentary Strata 95 Coastal Plains 12 Tertiary Sedimentary Strata 99 Coastal-Plain Terraces 15 Pleistocene Deposits 105 Shorelines 15 Phosphorite and Manganese Oxide 108 Continental Shelf 20 Synthesis and Paleogeography 116 General—Northeast Newfoundland Shelf—Grand Banks of Newfound• Structure 118 land—Gulf of St. Lawrence and Laurentian Channel—Scotian Shelf— Early Applications of Geophysics to Gulf of Maine, Bay of Fundy, and the Ocean 118 Northeast Channel—Georges Bank— Crustal Structure Inferred from Seismic Hatteras—Cape Cod Shelf—Florida— Refraction and Petrology 120 Hatteras Shelf—West Florida Shelf- Seismicity 126 Mississippi Delta—Texas—Louisiana Heat Flow 129 Shelf—East Mexico Shelf—Yucatan Magnetics 131 Shelf—Bahama Banks—Bermuda North American Continent—East- Continental Slopes 53 Coast Continental Shelf, Blake General—Grand Banks to Cape Plateau, Gulf of Mexico, Bahamas, Hatteras—Blake Plateau and and Caribbean—East Coast or Slope Escarpment—Southern Florida Slopes, Anomaly and Bahama Anomaly— Terraces, and Strait—Florida and Deep-Sea Floor—Mid-Atlantic Campeche Escarpments—Sigsbee Es• Ridge—Spreading History carpment and East Mexico Slope— Gravity 147 Mississippi Cone—Bahama Escarp• North American Continent—Atlantic ment, Upper Slope, and Deep Em- Continental Margin and Adjacent bayments—Outer Ridges Deep-Sea Floor—Bahamas—Gulf New England Seamount Chain and Other of Mexico—Caribbean Sea— Seamounts 72 Mid-Atlantic Ridge—Long-

Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/3839682/9781629812212_frontmatter.pdf by guest on 28 September 2021 wavelength Gravity Anomalies Particulate and Dissolved Organic Sedimentary Framework Inferred Largely Matter 306 from Seismic Reflection Profiles 160 Nutrient Salts 308 General—Continental Margin Zooplankton 309 North of Cape Hatteras— Neritic-Demersal Nekton 312 Continental Margin South of Neritic-Epipelagic Nekton 317 Cape Hatteras—Gulf of Mesopelagic Nekton 318 Mexico and the Caribbean— Bathypelagic and Abyssopelagic Structure and Isopach Maps Nekton 321 Benthic Biology 322 Water 227 General Composition on Continental Shelf—General Development of Knowledge 227 Composition Beyond Continental Tides 228 Shelf—Standing Crop and Tidal Currents 231 Productivity Sea Level 233 Relation to World Ocean 332 Seasonal Variation—Regional Trend—Variations During Past Sediments 333 Century—Variations During Past 5,000 Years—Variations During Development of Sedimentology in Past 35,000 Years—Variations the Region 333 Prior to 35,000 Years Ago and in Sources of Sediments 334 Future Ice—Sea Cliffs—Streams— Waves 249 Biogenic Sources—Wind Ordinary Wind Waves—Hurricanes— Shallow-Water Sediments 338 Tsunamis—Shelf Waves Estuaries and Lagoons—Salt Surface Water 256 Marshes and Mangrove Swamps— Color, Transparency, and Suspended Deltas—Sand Beaches— Sediments—Temperature and Calcareous Reef Sediments Salinity—Currents Above the Conti• Shelf Sediments 354 nental Shelf—Surface Currents in the Sources and Classifications— Gulf of Mexico—Gulf Stream Relict Sediments—Rafted Sedi• Subsurface Water 277 ments—-Residual Sediments— Shelf Water—Western North Authigenic Sediments—Biogenic Atlantic Water—Mediterranean Sediments—Detrital (Modern and Water—North Atlantic Deep Relict) Sediments—Radioactivity in Water—Norwegian Sea Overflow Sediments—Chemical Composition Water—Antarctic Bottom Water— of Sediments Western Boundary Undercurrent— Sediments of Blake Plateau 383 Depth of Oxygen Minimum Sediments of Straits of Florida and Bahama Troughs 386 Life 304 Straits of Florida—Tongue of the Ocean—Northwest Development of Knowledge in Providence Channel—Exuma the Region 304 Sound—Columbus Basin Primary Productivity 305 Continental-Slope Sediments 389

Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/3839682/9781629812212_frontmatter.pdf by guest on 28 September 2021 Sediments in Submarine Canyons 391 Thickness of Quaternary Sediments 413 Sediments of Gulf of Mexico 393 Pleistocene—Holocene Continental Rise 396 Sediment Volumes and Rates of Properties of Sediments— Deposition 417 Turbidity Currents—Western Boundary Undercurrent Origin of Continental Margin 420 Abyssal Plains 399 Seamounts, Bermuda Rise, and Tectonic Setting of North America 420 Abyssal Hills 402 Tectonic Concepts 425 Mid-Atlantic Ridge Sediments 403 Evolution of Continental Margin 428 Interstitial Water 405 Precambrian and Paleozoic Surface Sediment—Deeper History—Mesozoic History— Interstitial Waters Cenozoic History Mass Physical Properties 408 Consolidation-—Slope Stability—Acoustics References 442 Quaternary Climates 410 Index 504

Downloaded from http://pubs.geoscienceworld.org/books/book/chapter-pdf/3839682/9781629812212_frontmatter.pdf by guest on 28 September 2021 Preface

The Atlantic coast of North America was the first part of the New World to be de• scribed by maps and texts; its exploration began with the Vikings nearly a thousand years ago. Since then, the pace of exploration of both land and ocean floor has increased steadily. The concern during the past decade has been with details of geology, water, and life that largely were bypassed during earlier stages of discovery and exploration. The accumulation of knowledge is expressed approximately by the publication of charts, articles, and tabulations of data, and the number of these is increasing annually in al• most logarithmic progression. The writers believe that the time has come to assemble the information that has been gained to date in order to establish a generalized framework of knowledge on which future studies can be based. Such a framework also should be helpful for planning studies of continental margins elsewhere in the world where initial efforts are just beginning, or where studies have been delayed because of great distance from educational centers or lack of oceanographic skill or equipment. This book is concerned with the Atlantic continental margin of the United States, and it necessarily includes some information about the adjacent land and ocean areas. It is a summary, within the writers' limitations, of the existing knowledge of the ocean floor, the water above it, and the life that is in the water or at the bottom. By bringing together the information available concerning these materials, the writers hope that new relations will be revealed from which some paths for future work can be projected. Thus, the book is intended as a convenient reference for both oceanographers and interested lay• men. The material has many sources: oceanographic institutions, universities, government bureaus, and private companies. A concerted investigation of the Atlantic continental margin, inaugurated in 1962 by a team of geologists from the Woods Hole Oceano• graphic Institution and the U.S. Geological Survey, was the major inspiration for this book. Funds from the National Science Foundation and the Office of Naval Research made it possible for us to extend our study into the adjacent deep-sea and Bahama- Caribbean region. The writing was begun in 1968 with the interest and financial support of the Woods Hole Oceanographic Institution. In 1971, studies of the western Africa continental margin, supported by the International Decade of Ocean Exploration (Na• tional Science Foundation Grant 20/28193), aided the completion of the book and pro• vided comparisons between the once-adjacent North American and northwest African continental margins. More specific acknowledgments to scientists and organizations are made within appropriate sections of the text.

K. O. EMERY ELAZAR UCHUPI Woods Hole Oceanographic Institution Contribution Number 2929 Woods Hole, Massachusetts 02543 January 1, 1972