《SUBMARINE GEOLOGY》

Ⅰ. INTRODUCTION AND HISTORY1

Ⅱ. METHODS OF EXPLORING THE OCEAN FLOOR12

Obtaining Positions at Sea for Scientific Work13

Echo Soundings18

Grab or Snapper Samples20

Coring Devices22

Dredging25

Bottom photographs27

Sediment Traps30

Ripple-Mark Indicators31

Current Meters31

Geo-physical Prospecting33

Ⅲ. WAVES AND CURRENTS36

INTRODUCTION36

WIND WAVES37

Three Stages in Wave Development37

Wave definitions and Characteris-tics37

Breaking Waves40

Wave refraction 41

RIP CURRENTS (RIP TIDES OR UNDERTOW)43

DEPTH OF WAVE ACTION46

TSUNAMIS (TIDAL WAVES)47

The Hawaiian Tsunami of April1,194647

The April1,1946, Tsunami in Other Areas51

Wave Heights in Bays and on Points51

Conclusions Concerning Tsunamis52

OCEAN CURRENTS53

Wind Drift Currents53

Permanent Currents and the Prevailing Winds54

Bottom Currents Due to Sloping Sea Surfaces57

Tidal Currents57

Cur-rents Induced by Internal Waves58

Currents Associated with Tsunamis59

Suspension Currents 60

OBSERVED BOTTOM CURRENTS61

Currents in Submarine Canyons62

Currents on the Continental Shelves63

Currents on a Submarine Slope64

Currents in Basins and Troughs64

Cur- rents on Ridges, Banks, and Sills65

Summary of Information from Observed Bottom Currents65

Ⅳ. CLASSIFICATION OF SEA COASTS AND SHORELINES68

Definitions and General Considerations68

Objections to Previous Classi-fication69

Proposed Classification70

Discussion of the Classification76

Larger Subdivisions78

Ⅴ. BEACHES AND SAND SHIFTING ALONG THE SHORES80

GENERAL CONSIDERATIONS AND DEFINITIONS80

LOCATIONS IN WHICH BEACHES ARE FOUND81

BEACH CHARACTERISTICS83

Beach Profiles83

Beach Approaches, Submerged Bars and Rock Ledges84

Grain Size and Beach Gradients85

Beach Cusps86

BEACH CYCLES88

General Considerations88

Nature of Beach Retreat88

Nature of Beach Growth88

Explanation of the Reversal from Cut to Fill91

Importance of Longshore Drift94

Abnormal Beach Cycles95

SOURCES OF BEACH SAND96

PERMANENT Loss OF BEACH SAND98

PERMANENT BEACH CHANGES101

BEACH EROSION BY TSUNAMIS (TIDAL WAVES) AND BY HURRICANES102

Ⅵ. CONTINENTAL SHELVES: TOPOGRAPHY AND SEDIMENTS105

GENERAL CONSIDERATIONS AND DEFINITIONS105

DESCRIPTION OF THE CONTINENTAL SHELVES107

Eastern North America107

Eastern South America114

Western South Amer-ica115

Western North America116

Eastern Asia121

Australia126

Southern Asia128

East Africa129

West Africa131

Mediterranean Sea133

Western Europe134

The Arctic139

Antarctica141

Insular Shelves141

Shelves in Landlocked Bodies of Water142

SUMMARY OF SHELF TOPOGRAPHY143

Some Debunking and Some Statistics143

Shelves off Glaciated Areas145

Shelves off Large Rivers146

Shelves in Areas of Active Coral Growth146

Shelves off Young Mountain Ranges146

Shelves Associated with Strong147

DEEPS AND SHOALS AT BAY ENTRANCES147

SHELF MARGINAL DEPTHS IN RELATION TO WIDTH148

SHELF MARGINAL DEPTHS IN RELATION TO EXPOSURE TO STORM WAVES149

SUMMARY OF SHELF SEDIMENTS150

More Debunking and Some Generalization150

Shelf Sediments off Gla-ciated Coasts151

Sediments off Large River Mouths151

Sediments of Open Shelves Compared with Those of Closed Bays and Gulfs152

Bottom Char-acter in Narrows152

Bottom Character off Points of Land152

Sediment off Long Beaches153

Bottom Character on Shelf Hills and Ridges153

Sediment in Depressions of the Open Shelves153

Sediment Types at the Shelf Mar-gin153

Environments Favorable to the Principal Types of Bottom154

Ⅶ. ORIGIN AND HISTORY OF THE CONTINENTAL SHELVES157

INTRODUCTION157

PREVIOUS SUGGESTIONS158

FACTS REQUIRING EXPLANATION158

NONDEPOSITIONAL SURFACES ON THE SHELF160

Availability of Mud Sediments160

Seaward Transport of Sand161

Gravel and Cobbles on the Outer Shelf162

Glauconite on the Shelves162

Overlap-ping Deposits163

Rock Bottom on the Shelves 164

SHELF-FORMING AGENCIES165

Wave Erosion165

Marine Clastic Deposition168

Delta Deposition168

Lime-stone Deposition170

SHELF GLACIATION171

EROSION BY CURRENTS172

CONCLUSIONS REGARDING THE SHELF ORIGIN173

Ⅷ. CONTINENTAL SLOPES175

INTRODUCTION175

DESCRIPTION OF THE CONTINENTAL SLOPES175

Eastern North America175

South America178

Western North America180

Eastern Asia184

Indian Ocean185

West Africa186

Mediterranean Sea186

West-ern Europe187

SUMMARY OF CONTINENTAL SLOPE CHARACTERISTICS187

CONTINENTAL SLOPES RELATED TO COASTAL TYPES188

Coasts with Deltas and Large Rivers188

Fault Coasts188

Young Mountain-Range Coasts (Other than Fault Coasts)188

Stable Coasts, Lacking Large Rivers188

SLOPES IN RELATION TO OCEAN BASINS189

ORIGIN OF THE CONTINENTAL SLOPES190

General Considerations190

Wave-Built Terraces190

Downwarped Continen-tal Surfaces191

Fault Scarp or Fault Zone193

MODIFICATION OF CONTINENTAL SLOPES194

Effects of Deposition194

Submarine Landslides195

Lava Flows and Coral Growth as Possible Factors in Slope Origin198

ORIGIN OF CONTINENTAL BORDERLANDS198

CONCLUSIONS REGARDING THE CONTINENTAL SLOPE ORIGIN199

CONTINENTAL SLOPE AND BORDERLAND DEPOSITS COMPARED WITH SHELF DEPOSITS199

A Stratigraphic Problem199

Faunal Evidence200

Nondepositional Surfaces203

Character of Recent Deposits203

Ⅸ. SUBMARINE CANYONS207

HISTORICAL BACKGROUND207

SUBMARINE CANYONS FROM VARIOUS PARTS OF THE WORLD COMPARED209

Oceanographer Canyon, New England Coast211

Mississippi Canyon or Trough213

Monterey Canyon, California215

Bering Canyon216

Tokyo Can-yon218

Toyama Canyons220

Luzon Canyons, Philippine Islands220

Indus Canyon221

Congo Canyon223

West Corsica Canyons225

Nazaré Canyon, Portugal227

Cap Breton Canyon, Southwestern France228

SUMMARY OF CANYON CHARACTERISTICS229

CANYON DISTRIBUTION231

General Consideration231

Distribution in Relation to Coastal Types and Coastal History232

Canyons Related to River Mouths233

LAND BORINGS INSIDE SUBMARINE CANYONS234

OUTER TERMINATIONS OF SUBMARINE CANYONS234

VALLEYS AND CANYONS ADJACENT TO OCEANIC ISLANDS235

CHANGING HEADS OF SUBMARINE CANYONS236

ORIGIN OF THE SUBMARINE CANYONS237

Diastrophic Origin237

Suspension (Density) Currents238

Submarine Spring Sapping239

Submarine Mud Flows and Landslides240

Tsunamis (Tidal Waves)240

Excavation by Rivers241

Marginal Movements or Sea-Level Changes243

ADVANTAGES OF THE GLACIAL-CONTROL AND MARGINAL-WARPING HYPOTHESIS245

The Distribution of the Canyons Around the World245

The Flat-topped Seamounts and Deep Banks of the Pacific247

The Apparent Pleistocene Age of the Canyons247

The Numerous Reports of Gravel, Cobbles, and Shallow-Water Shells in Deep Water248

OBSTACLES CONFRONTED BY THE GLACIAL-CONTROL AND248

MARGINAL-WARPING HYPOTHESIS248

Ⅹ. CORAL REEFS251

FACTUAL INFORMATION251

Coral Reefs Defined251

Ecology of Reefs252

Lagoon Floors; Depth and Bot-tom Character256

Special Features of Atolls and Barrier Rims260

Slopes Outside Coral Reefs262

Geophysical Exploration and Borings in Reefs262

CORAL-REEF HYPOTHESES264

Darwin's Subsidence Hypothesis264

Daly's Glacial-Control Hypothesis268

Solution of Lagoons271

Lagoons Due to Upgrowth on Antecedent Plat-forms272

RECENT NEGATIVE SHIFTS OF SEA LEVEL273

CONCLUSIONS REGARDING CORAL REEFS275

Ⅺ. THE FLOOR OF THE DEEP OCEANS279

HISTORY OF EXPLORATION279

DESCRIPTION OF MAJOR RELIEF FEATURES OF THE OCEANS280

The Atlantic280

The Pacific281

The Indian Ocean288

The Mediterraneans-Small Landlocked Deeps288

SEA-FLOOR DEPOSITS292

History of Investigations292

Classification of Deep-Sea Deposits292

Red Clay293

Pelagic Oozes297

Terrigenous Muds298

Glacial Marine Sediments298

Volcanic Sediments299

Distribution of Deep-Sea Deposits299

Nondeposi-tional Surfaces of the Deep Sea303

Deposits of Deep Marginal Basins304

Rates of Deposition of Deep-Sea Deposits305

Deposition in Deep Basins near Land308

Slumping in Deep-Sea Deposits309

EXPLANATION OF THE IRREGULAR FLOOR OF THE OCEAN309

ORIGIN OF THE ISLAND ARCS AND ASSOCIATED DEEPS311

ORIGIN OF THE OCEAN BASINS313

Foundering of the Continents314

Wegener's Hypothesis314

Birth of the Moon from the Pacific315

Ⅻ. SUMMARY AND ECONOMIC APPLICATIONS320

INCREASING SIGNIFICANCE OF SUBMARINE GEOLOGICAL INVESTIGATIONS320

EQUIPMENT FOR THE INVESTIGATION OF SUBMARINE GEOLOGY321

WAVES, CURRENTS, AND ENGINEERING STRUCTURES322

ORIGIN OF THE CONTINENTAL SHELVES325

THE SIGNIFICANCE OF GLACIATED SHELVES326

CONTINENTAL-SHELF INVESTIGATIONS AND OIL POSSIBILITIES327

MAPPING OIL STRUCTURES ON THE CONTINENTAL SHELVES328

CONTINENTAL SLOPES AND THEIR TECTONIC SIGNIFICANCE330

INDICATIONS OF LARGE WORLD-WIDE SUBMERGENCE332

Submarine Canyons as Submerged River Valleys332

Flat-Topped Sea-mounts (Guyots)333

Gravel and Cobbles in Deep Water334

Submerged Atolls334

Filled Canyon Heads Along the Coasts and Their Economic Significance335

THE POSSIBLE SIGNIFICANCE OF THE SUBMERGENCE DATA335

APPENDIX. CONVERSION TABLES337

CHART Ⅰ. BATIIYMETRIC CHART OF THE WORLD facing p.338

INDEX339