Geophysical Monograph series American Geophysical Union......Page 1
The Geophysics of the Pacific Ocean Basin and Its Margin......Page 3
The Geophysics of thePacific Ocean Basin andIts Margin......Page 4
Foreword......Page 6
Preface......Page 9
Contents......Page 10
2. Gravity Field of the Northwest Pacific Ocean Basin and Its Margin'......Page 28
GRAVITY MEASUREMENTS......Page 29
FREE-AIR ANOMALY MAPS......Page 30
DISCUSSION OF THE GRAVITY ANOMALY AND TOPOGRAPHY PROFILES......Page 36
INTERPRETATION OF THE MAIN FEATURES OF THE GRAVITY ANOMALY MAPS......Page 41
3. Gravity Measurements Near Japan and Study of the Upper Mantle Beneath the Oceanic Trench-Marginal Sea Transition Zones......Page 46
CHARACTERISTICS OF THE FREE-AIR GRAVITYANOMALIES IN AND AROUND JAPAN......Page 47
ESTIMATION OF THE UPPER MANTLE STRUCTURE FROM GRAVITY ANOMALIES......Page 48
DISCUSSION......Page 62
4. Airy-Woollard Isostasy......Page 64
DERIVATION OF BASIC AIRY SYSTEM FORMULAS......Page 65
AUGMENTED AIRY-WOOLLARD ISOSTASY......Page 67
SOME IMPLICATIONS OF AIRY-WOOLLARD ISOSTASY......Page 68
5. A Simulation Study for Sub-Meter Geodesy in the Pacific Basin......Page 69
THE DOPPLER RANGE EQUATION......Page 70
THE COMBINATION SOLUTIONS......Page 72
NOTATION......Page 75
6. Regional Gravity of Peru......Page 76
7. Seismological Studies of the Pacific Area: Introduction to Session 2......Page 77
8. Crustal Structure of the Peru-Chile Trench: 8°-12° S Latitude'......Page 79
OBSERVATIONS......Page 80
RESULI S......Page 81
DISCUSSION......Page 88
SUMMARY......Page 93
SEISMICITY......Page 94
DISTRIBUTION OF PRINCIPAL LINES OF STRESS......Page 102
THE CURVATURE OF THE SLAB......Page 103
TECTONIC PATTERN......Page 105
METALLOGENESIS IN BOLIVIA AND THENAZCA PLATE......Page 107
SUMMARY......Page 110
10. Project Nariftol III: Refraction Observation Across a Leading Edge, Malpelo Island to the Colombian Cordillera Occidental......Page 111
PRELIMINARY RESULTS FROM OTHER STUDIES......Page 112
THE PRINCIPAL DATA SET......Page 114
ON THE QUESTION OF CONSTRAINTS......Page 115
A FIRST MODEL ACROSS THE LEADING EDGE? STARTING ASSUMPTIONS......Page 131
THE MODEL AND DISCUSSION......Page 132
SUMMARY AND CONCLUSIONS......Page 137
11. Attenuation of Rayleigh Waves Along the East Pacific Ridge......Page 139
12. Observation of Earthquakes and Explosions at the Bottomof the Western Pacific: Structure of Oceanic LithosphereRevealed by Longshot Experiment......Page 140
SOME RESULTS ON OBSERVATIONSOF NATURAL EARTHQUAKE......Page 141
EXPLOSION SEISMOLOGY......Page 145
RESULTS OF THE SECOND LONGSHOT......Page 146
STRUCTURE OF THE UPPER MANTLE......Page 150
DISCUSSION AND CONCLUSIONS......Page 156
13. Ocean-Bottom Seismograph Study of the Western Margin of the Pacific......Page 159
OBSERVATIONS OFF SANRIKU NEAR THE JAPAN TRENCH......Page 160
OBSERVATIONS IN THE MARIANA REGION......Page 167
OBSERVATIONS ON THE FIJI PLATEAU......Page 171
SEISMIC ACTIVITY ON THE ISLAND OF HAWAII......Page 172
SEISMICITY RELATED TO SHALLOW VOLCANISM......Page 174
15. Magnetic Studies of the Pacific Area: Introduction to Session 3......Page 176
16. Post-Eocene Plate Tectonics of the Eastern Pacific'......Page 179
DATA PROCESSING AND ANALYSIS......Page 180
REGIONAL PATTERNS......Page 185
REGIONAL KINEMATIC ANALYSIS......Page 196
CIRCUM-PACIFIC TECTONIC IMPLICATIONS......Page 204
17. The Early Cretaceous-Late Jurassic Magnetic Reversal Time Scale,and the Phoenix Magnetic Lineations Revisited......Page 205
18. Mesozoic Sea-Floor Spreading in the North Pacific......Page 206
GEOLOGY AND REGIONAL DESCRIPTION......Page 207
MAGNETIC ANOMALIES......Page 212
EVOLUTION OF THE NORTH PACIFIC......Page 222
19. An Age-Dependent, Two-Layer Model for Marine Magnetic Anomalies......Page 228
METHOD......Page 229
DATA ANALYSIS......Page 230
DISCUSSION......Page 233
CONCLUSIONS......Page 235
20. Magnetic Anomalies in the Sea of Japan and the Shikoku Basin: Possible Tectonic Implications......Page 236
MAGNETIC ANOMALIES IN THE JAPAN SEA......Page 238
NUMERICAL TEST OF SYMMETRY AND POSSIBLE SPREADING CENTERS......Page 239
OTHER GEOPHYSICAL EVIDENCE......Page 241
AGE CONSTRAINTS ON SPREADING PERIODS......Page 243
A HYPOTHESIS FOR THE EVOLUTION OF MARGINAL BASINS AROUND THE JAPANESE ISLANDS......Page 246
SOME IMPLICATIONS ON THE CENOZOIC GEOLOGY OF JAPAN......Page 250
21. Magnetic Anomalies in the West Philippine Basin'......Page 253
ANALYSIS OF THE MAGNETICS......Page 255
BATHYMETRIC DATA......Page 261
CONCLUSIONS......Page 267
22. Anomalies in the Tectonic Evolution of the Pacific......Page 268
CONCLUSIONS......Page 276
23. Cenozoic Plate Motion and the Magnetic Time Scale, Equatorial Pacific......Page 278
24. Cenozoic History of the Central Equatorial Pacific: A Synthesis Based on Deep Sea Drilling Project Data......Page 279
REGIONAL LITHOLOGY AND TECTONIC HISTORY......Page 281
SEDIMENT ACCUMULATION AND CARBONATE DISSOLUTION......Page 284
HIATUSES AND EROSION......Page 289
PALEO-OCEANOGRAPHIC HISTORY......Page 291
Sea Water, Sea-Floor Spreading, Subduction, and Ore Deposits......Page 294
26. Contrasts in Tectonic History Along the Eastern Pacific Rim......Page 295
NORTH AMERICAN CORDILLERA......Page 297
CENTRAL ANDES......Page 298
THE SCOTIA SEA REGION......Page 299
CONCLUSIONS......Page 303
EARLY WORK IN HAWAII......Page 305
THE HALEMAUMAU LAVA LAKE......Page 308
CALDERAS AND VOLCANO-TECTONIC DEPRESSIONS......Page 309
DOMES......Page 311
GLOBAL TECTONICS AND VOLCANISM......Page 312
RELATIVE SPREADING RATES IN THE PACIFIC......Page 314
THE FIXED HOT SPOT HYPOTHESIS......Page 316
GEOCHRONOLOGICAL DATA ON LINEAR ISLANDCHAINS IN THE PACIFIC......Page 319
CAUSES CONTRIBUTING TO IRREGULAR VOLCANIC PROPAGATION......Page 326
CONCLUSIONS......Page 330
29. Mechanics of Ben ioff Zone Magmatism......Page 331
PETROLOGY OF ANDESTTE PRODUCTION......Page 333
MAGMA DYNAMICS......Page 335
THERMAL MODELS, SHEAR STRESSAND SHEAR ZONE THICKNESS......Page 341
DIRECT SOURCE DETECTION......Page 343
30. Chemical Diversity of Abyssal Volcanic Glass Erupted Along Pacific, Atlantic, and Indian Ocean Sea-Floor Spreading Centers......Page 345
SAMPLE PROPERTIES......Page 346
SORTING AND CLASSIFICATION OF ANALYSES......Page 347
CHEMICAL DIVERSITY......Page 354
REGIONAL PATTERNS......Page 355
COMPARISONS OF SPREADING CENTERS......Page 361
31 . 4o A r / 39Ar Ages of Submarine Rocks from the Line Islands:Implications on the Origin of the Line Islands......Page 362
DISCUSSION......Page 365
32. Kilauea Lava Lakes: Natural Laboratories for Study of Cooling, Crystallization, and Differentiation of Basaltic Magma......Page 368
METHODS OF STUDY......Page 369
INTERPRETATIONS OF COOLING AND CRYSTALLIZATION HISTORY......Page 370
INTERPRETATION OF SURFACE ALTITUDE CHANGES:DENSITY CHANGE ON SOLIDIFICATIONAND DISTRIBUTION OF VESICLES......Page 379
Alae lava lake......Page 382
Prehistoric Makaopuhi lava lake......Page 383
33. Phase Transformations in Descending Plates: Implications for Mantle Dynamics and Differentiation......Page 384
PHASE TRANSITIONS IN SINKING SLABS THERMAL EFFECTS......Page 387
PHASE TRANSITIONS IN SINKING SLABS: EFFECTS OF CHEMICAL HETEROGENEITY......Page 389
DEPLETION OF LIGHT REE, Ba, U, AND Rb IN OCEANIC THOLEIITES......Page 390
34. Mineralogic Distribution of Iron in the Upper Half of the Transition Zone in the Earth's Mantle......Page 392
PARTITION OF Mg 2+ AND Fe2+ IN OLIVINE-GARNETAND SPINEL-GARNET SYSTEMS......Page 393
MINERALOGY OF THE MANTLE DOWN TO 650 KM......Page 395
TEMPERATURE GRADIENT IN THE TRANSITION ZONE......Page 397
35. Elastic Properties of Selected Ophiolitic Rocksfrom Papua New Guinea: Nature and Compositionof Oceanic Lower Crust and Upper Mantle'......Page 399
GEOLOGIC SETTING OF PAPUANOPHIOLITE COMPLEX......Page 400
RESULTS AND DISCUSSION......Page 401
TEST OF DAVIES' CRUSTAL MODEL FORCOASTAL EASTERN PAPUA......Page 410
CONCLUSIONS......Page 413
MANTLE GRAVITY ANOMALY AND THE UPPER MANTLE STRUCTURE......Page 414
THERMAL MODEL OF THE THICKENING LITHOSPHERE......Page 415
REGIONAL VARIATIONS OF RAYLEIGH WAVEDISPERSION IN THE PACIFIC......Page 417
PETROLOGICAL CONSIDERATION......Page 419
CONCLUSION......Page 421
37. Lithospheric Flexure, Analysis of Gravity Anomalies, and the Propagation of Seam ount Chains......Page 422
GENERAL THEORY OF PLATE LOADING......Page 423
PART A: STATISTICAL ANALYSIS OF GRAVITY ANOMALIES......Page 424
DISCUSSION......Page 425
PART B: PROPAGATION OF SEAMOUNT CHAINS......Page 426
SUMMARY......Page 428
Earth Scientists Are Like Other Scientists, Only Maybe Worse......Page 430
Envoi The International Woollard Symposium......Page 431
References......Page 432
Subject Index......Page 462