Seamounts, Islands, and Atolls

Seamounts, Islands, and Atolls......Page 1
Geophysical Monograph Series......Page 2
Seamounts, Islands,and Atolls......Page 4
CONTENTS......Page 6
FOREWORD......Page 10
A Brief Review of the "Simple" Hotspot Model......Page 11
Origin of Hotspots; Petrology and Chemistry......Page 12
Plate Kinematics......Page 13
Interaction with the Plate......Page 15
Geochemistry and Origin of Hotspots......Page 16
A Final Perspective......Page 17
References......Page 18
Introduction......Page 22
Results and Discussion......Page 24
Conclusions......Page 29
References......Page 30
The Depth Anomaly Map......Page 31
PossibleC ausesf or the Superswell......Page 35
Mechanismo f Heat TransporItn to the Superswell......Page 36
Causes for a Thinner Lithosphere......Page 37
Conclusions......Page 38
References......Page 39
Introduction......Page 41
Pacific Plate Seamcunt Near the EPR at 11ø30......Page 43
Cocos Plate Seamounts at 12ø42? and 12ø50......Page 45
Older Seamounts on the Cocos Plate......Page 48
Irregular Morphology of Volcanoes......Page 49
Origin of Oblique Faults......Page 50
Referenc es......Page 51
The Submerged Platform......Page 54
Terrace Structures......Page 55
Shallow Slopes......Page 56
Rock Types......Page 58
Side-Scan Sonar Bathymetry......Page 60
Evidence for Tilting......Page 61
Discussion of Dive Results......Page 62
mplications......Page 63
References......Page 64
Morphology of Mariana Forearc Seamounts......Page 65
Stability Fields of Metamorphic Facies in a Convergent Margin......Page 68
Subduction-Related Fluids in the Forearc......Page 69
Discussion......Page 71
References......Page 72
Regional Framework......Page 74
Sedimentary Basin Stratigraphy......Page 75
Edifice Structure......Page 78
Gravity......Page 80
Conclusions......Page 84
References......Page 85
Introduction......Page 86
Three-Dimensional Models of Sio and Ira Mai Tai Guyors......Page 87
Eruptive Centers or Conduits......Page 89
Generalized Three Dimensional Seamount Gravity Models......Page 90
Isostatic Compensation and Age of Loading......Page 93
Regional Clustering of Compensation Levels......Page 94
Discussion......Page 95
References......Page 96
Introduction......Page 98
Gravity Effect of Seamount Topography......Page 100
Least-Sauares Method for Density Determination......Page 102
Results......Page 105
Effect of Heteroeeneous Structure of Seamounts......Page 109
Relationo f SeamounDt ensitiesto TheirD epths......Page 111
High Gravity Anomaly Calderas......Page 112
References......Page 113
Previous Studies......Page 115
Location Method......Page 116
Results of the SEAPSO V Cruise......Page 117
Seamcunt S6 Figure 4......Page 118
Seamount S5 Figure 5......Page 119
References......Page 121
Introduction......Page 123
The Forward Problem......Page 124
The Inverse Problem......Page 125
Results......Page 126
Marquesas......Page 128
Discussion......Page 130
References......Page 131
Geologic and Tectonic Background......Page 133
Seamount Paleomagnetism......Page 137
Data......Page 138
Paleomagnetic Models 3D......Page 139
Paleomagnetic Models 2D......Page 144
SeamounAt ges......Page 147
A New Pacific Apparent Polar Wander Path......Page 149
Paleopoles, Magnetic Ages, and Possible Rotations......Page 151
Paleolatitudes......Page 154
Tectonic Model......Page 155
Section A: Miscellaneous Tables......Page 158
References......Page 159
Regional Setting and History of Volcanism in the Marshall Islands......Page 163
Previous Studies on the Timing and Magnitude of Subsidence in the Region......Page 164
Geology and Geophysics of Harrie Guyot......Page 166
Geologya nd Geophysicosf SylvaniaG uyot and Bikini Atoll......Page 168
Conclusions......Page 170
References......Page 171
Forearc Tectonics......Page 173
Mariana Forearc Seamounts......Page 174
Paleontology and Depositional Environments......Page 175
Diagenesis......Page 176
Discussion......Page 179
Conclusions......Page 180
References......Page 181
Introduction......Page 184
Seamount Sedimentation......Page 185
Seamounts of the Eastern Pacific Ocean......Page 186
Field Work......Page 187
Visual and Photographic Observations......Page 188
Grain-Size Analyses......Page 192
Large-Scale Factors Affecting Sedimentation......Page 194
Intermediate-Scale Factors Affecting Sedimentation......Page 195
Small-Scale Factors Affecting Sedimentation......Page 196
References......Page 198
Introduction......Page 201
Samples and Methods......Page 202
Alteration and the Effects of Leaching......Page 203
Summary of Plateau Basalt Isotopic and Chemical Data......Page 207
The Sources of the Pacific Plateaus......Page 208
Conclusions and Summary......Page 211
References......Page 212
MINERALOGICAL STUDIES OF SAMOAN ULTRAMAFIC XENOLITHS: IMPLICATIONS FOR UPPER MANTLE PROCESSES......Page 215
Introduction......Page 228
Sample Sites......Page 230
Petrology......Page 232
Mineralogy......Page 234
Discussion of Petrogenesis......Page 236
Nature of the Mantle Source......Page 239
Summary......Page 245
References......Page 246
Introduction......Page 248
Cr-Rich Spinel......Page 249
Plagioclase......Page 252
Olivine......Page 255
Clinopyroxene......Page 256
Whole Rock Chemistry......Page 257
Geothermometry......Page 258
Discussion......Page 261
Evidence for Mixing......Page 262
Fractionation......Page 263
Evidence for Source Region Heterogeneity......Page 267
Conclusions and Implications for Adjacent EPR Source......Page 270
References......Page 272
2. Geological Setting and Sampling......Page 276
4. Seafloor Alteration Effects......Page 277
4.1. Leaching Experiments......Page 278
4.2. Discussion......Page 280
5. Data Measured on Leached Samples......Page 282
6.1. Multiple Flow Units on Single Seamount......Page 283
6.2. Mantle Source......Page 284
6.3. Implicationsfo r the Hotspot Theory......Page 285
References......Page 287
Introduction......Page 290
Petrography and Chemistry......Page 292
Welker Guyot......Page 293
Miller Seamount......Page 295
Patton Seamount......Page 296
Magma Supply Rates and Eruption Depth,s.......Page 298
Results......Page 299
Discussion and Conclusions......Page 303
Pratt-Welker......Page 304
Patton-Murray......Page 305
Pathfinder-Horton......Page 306
References......Page 307
Introduction......Page 309
Nutrients and Primary Productivity......Page 310
Zooplankton and Nekton......Page 312
Ecology of Seamount Benthos......Page 315
Deep Seamounts--Effects of Substratum and Current s......Page 316
The Role of Seamounts in Fisheries productivity......Page 319
Conclusions and Suggestions for Future Research......Page 320
References......Page 321
Introduction......Page 325
Geological Aspects of Seamount Effects on Circulation......Page 326
I. Homogeneous Flows......Page 327
II. Stratified Flow......Page 330
Observations of Seamount Effects on Circulation......Page 332
Observations of Seamount Chain Effects on Circulation......Page 338
Conclusions......Page 341
References......Page 343
Introduction......Page 345
Plants and Invertebrates......Page 347
Fishes......Page 354
Biomeographic Patterns......Page 355
Origins of Biogeographic Patterns......Page 358
References......Page 364
Introduction......Page 368
Methods......Page 369
Results......Page 371
Discussion......Page 373
References......Page 378
Introduction......Page 380
Bathymetry......Page 382
The Gravity Data......Page 383
Structural Pattern......Page 384
Isostatic Anomaly Maps and Thickness of the Lithosphere......Page 385
Thinning of the Lithosphere......Page 390
Discussion and Conclusions......Page 391
References......Page 393