INDEX

Absolute age of basement,Site 319, 443

Abyssal depth,defined, 747

AF demagnetization, methods of, 485Age-depth dependence of elements, 306Algae, calcareous, 623Allanite, 612Alteration, basalt, 92, 239, 446, 502, 766

depth of, 435factors regulating, 433halmyrolitic, 435, 467, 523minerals formed during primary cooling, 399nonoxidative, 463oxidative, 405, 445, 463products, 385rate of, 433topography effect on, 767by seawater, 286, 301, 305, 306, 399

Alteration, titanomagnetite, 353, 358Alternating-field demagnetization, 501Amorphous colloids (RSO), 612, 621Amphibole, 614Amphiropalum ypsilon Zone, 713Andes Mountains, pyroclastic activity in, 116, 605, 611Angular unconformity, 122Anisotropy of magnetic susceptibility (AMS), 495Anthocyrtidium angulare Zone, 713Apatite, 615Ar40/Ar39 ages, 455, 763Aragonite, 409Aragonite-calcite relationship, 423Augite, 765Authigenic minerals, 606, 619

sediments, 785silicates, 606

Barite, 615Barium, geochemistry of, 570

in basalt, 284Basal sediments, formed from volcanic activity, 569

major constituents of, East Pacific, Rise, 561, 564Site 321, 116, 117

Basalts, alteration of, 92, 239, 390, 446, 502, 766barium concentrations in, 284Bauer Deep, 190, 200, 618cesium concentrations in, 284chemistry of, 190, 218, 239, 278, 386chrome spinel in, 91comparative average analyses of, 192comparison with altered, 377

with dredged, 337with Leg 26, 194

compressional wave velocities of, 543-550cooling units, 234coring, evaluation of, 183-185

recovery, 183elastic properties of, 543

electrical resistivity of, 549-551electron microprobe analyses of, 273element distribution patterns, 293emplacement mode of, 495eruption of in an abyssal environment, 368fission track age, 451, 455, 743fractional crystallization of, 194, 224hydrothermal veins in, 377Indian Ocean, 285lead isotope composition, 343, 764magnetization of, 90, 121, 469, 529

NRM intensity of, 77VRM in, 473, 479-483, 527, 773

major and trace element chemistry, 191,239-243,264,289, 293, 764

mid-ocean ridge, 264, 285, 289, 306, 763Nazca plate, 87, 123, 189, 190, 215, 218, 245, 764

petrography of, 227-235, 246nondestructive measurements, 501normative mineralogy and classification of, 192olivine in, 254, 364opaque mineralogy of, 381oxidative alteration of, 445, 463Paleomagnetism of, 513-532phase chemistry, 198, 248Plagioclase in, 270, 364porosity of, 550potassium-argon age of, 439-446, 773potassium concentrations, 284produced at spreading ridge, 763pyrite in, 377rare-earth element patterns, 240, 763relationship of seismic velocities to weathering, 544remagnetization of, 523seawater alteration, 286, 301, 395, 306Site 319, 27, 34, 248, 270, 271, 273, 274, 279,445,449,

743Site 320, 87, 91, 248Site 321, 117, 123, 248, 446, 449subaerial, 357Sr concentration in, 283sulfur concentration in, 364, 375tectonic environment of eruption, temperature

alteration of as related to magnetization, 170texture, 27, 264, 271, 273, 274

as a reflection of cooling, 189formation of, 29

thorium concentrations, 343trace elements in, 191, 239-243, 289, 293uranium concentrations, 343, 452, 455weathering of, 291, 433, 440XRF analyses of, 239, 263

Basalt-sediment contact, 116, 117Basaltic glass, 363, 364, 382Bathyal depths, defined, 747Bauer Deep, 19-35, 190, 618

basalt in, 190, 200, 27-35

809

bathymetry and structure of, 157-160carbonate compensation depth, 21faults in, 157geologic history of, 159metalliferous sediments in, 3, 19, 33, 786, 803pillow lavas, 3See also Site 319

Benthonic faunas, 635, 636Biogenic components, 771Biostratigraphic zonation, basis for, 13, 789Biotite, 615Birnessite, formation of, 415, 416

occurrence in submarine basalts, 423Bottom currents, 561Bottom-hole assembly, monel, 526Calcite, 386, 409

formed during oxidative diagenesis, 419Carbon and carbonate analyses, 11, 601Carbonate compensation depth, 635, 747, 749

fluctuation of during the Quaternary, 749Site 319, 33Site 321, 116, 120

Catinaster coalithus Zone, 716Cation-deficient titanomagnetite, 358, 462, 523, 767,

773, 774Celadonite, diagenetic, 389, 395Central Water Mass, properties of, 714Ceratolithus primus Subzone, 715

tricomiculatus Zone, 708Cesium concentrations in basalt, 284Chalcopyrite, 358, 377Chemical analysis of basalt, 190, 239, 278, 386Chlorite, 615Chrome spinel, 91Cipero Formation, 747Clay minerals, chemical analyses of, 383

X-ray diffraction analysis of, 386, 795Clinoptilolite, 615Clinopyroxene, 615

volcanic, 606Core disturbance, 11Core handling, 9Crystal fractionation, 242, 291, 301, 305, 306Curie points, 480Curie temperatures, 480, 549Cyclicargolithus abisectus Subzone, 716Deuteric minerals, 395Diagenesis, nonoxidative, 405, 429

oxidative, 417Diagenetic assemblage, Group I, 413

Group II, 414Diagenetic minerals, 389, 395Diatoms, Rhizosolenia praebergonii Zone, 718

Site 320, 715Site 321, 718

Dictyocha/Distephanus ratio, 715, 719Dictyocha epiodon Zone, 715, 720

perlaevis delicata Zone, 719Dinoflagellates, Site 321, 742Discoaster calcaris Zone (NN10), 29, 709

deßandrei Subzone, 716druggi Zone, 89, 711exilis Zone (NN6), 30, 709hamatus Zone, 715

neohamatus Zone, 715quinqueramus Zone, 709, 715

Distephanus boliviensis boliviensis Zone, 719Dolomite, 615, 620Duluth gabbro, 386East Pacific Rise, 33

spreading rate, 561topography of, 19

Easter Fracture Zone, 160Easter Island as a volcanic source, 27Eastern Boundary Current, 794Ebridians, 718Elastic flexture, oceanic crust, 175Element distribution patterns in basalt, 293Eolian debris, 619

transport, 629Epigenetic pyrite, deposition of, 389

in ocean floor basalts, 381-384Feldspars, 251, 252, 253, 615Ferromanganese nodules, 581Fibropalagonite, 402, 616Fish debris, 615Fission track dating, basalts, 451Foraminifera, benthonic, 743

diversity of assemblages, 763Phase I, 749Phase II, 749Phase III, 749Site 319, 29, 635Site 320, 636

Foraminifera, planktonic,dissolution of, 635, 636N2, 89, 749N4, 88, 89N6, 783N8, 441, 443, 635, 749N8/N9 boundary, 443N9, 446, 635N10/11, 29N12, 29N20, 89N21, 89N22, 89N23, 89P16, 119, 637, 749P17, 749P18, 119P19, 119, 749percentage of, 631Site 319, 29, 635Site 320, 636Site 321, 636, 637stratigraphic distribution of, 743

Paleogene, 119Systematics, 637-704

Fractional crystallization, 293Galapalagos Rise, 3, 33

crust formation, 175disappearance of, 19

Geochemistry, oxygen-isotope, 337, 338sediments, 552Site 319, 30, 89Site 321, 90, 120

Gephyrocapsa oceanica Zone, 711

810

Glass, 616in basalt, 364volcanic, 605, 783

Glauconite, 389Goethite, 616

occurrence of in submarine basalts, 423Grain-size analyses, 11, 603Grijalva Ridge, 160Halite, 616Halmyrolitic alteration, 523

basalt, 467Halmyrolysis, 357, 360, 435, 452, 462, 564, 774Heat-flow, method, 553

Site 319, 553Helicopontosphaera ampliaperta Zone, 714Hematite, 270

occurrence in submarine basalts, 463High-field magnetic moment, 508Hopkinson peak, 511Hornblende, volcanic, 606Humboldt Current, 89, 91

history of, 3influence of, 7, 715initiation of, 116

Hydrothermal deposition, 384Hydrothermal leaching, 564Hysteresis, 501

high-field, 510low-field, 506

Iddingsite, 399Ilmenite, petrography of, 358Indian Ocean basalts, 285Induced magnetization, 527Initial susceptibility, 466, 479, 501Instrumental Neutron Activation Analysis, 239Interstitial water analyses, 625-628

Site 319, 625Site 320, 625Site 321, 625

Iron hydroxides, petrography of, 358Island arc volcanism, 617Isotope analyses, 386

oxygen, 386sulfur, 381, 385

K-Ar ages of basalt, 439-452, 763K-feldspar, authigenic, 606, 619

interstitial, 266volcanic, 605

Kilauea Volcano, 399Königsberger ratios, 479, 502Kreyenhagen Formation, 747Large-ion lithophile (LIL) elements, 294, 303, 305

depletion of in upper mantle, 306Laumontite, 395Lead isotopic composition, basalt, 343, 764Lithophile trace elements, 240Low-field hysteresis, 506Lop-P differentiation, 274Low-temperature alteration, See halmyrolysisMagmas, evolved, 242Magmatic fractionation, 239

minerals, high-temperature crystallization, 429sulfides in basaltic glass, 363

Magnetic anomalies, 511anomaly 16, 81mineralogy, 479, 489moment, 501patterns, Site 321, 321properties of basalt and sediments, 90, 151, 459

469, 529, 769-778reversals, 535viscosity coefficient, 481

Magnetization, induced, 767thermoremanent, 524viscous, 475, 767

Major element chemistry, basalt, 239-243, 264, 293abundance of in Leg 34 basalts, 239-243,

264, 293, 764Manganese, occurrence in submarine basalts, 423

nodules, 413Marcasite, 118, 363, 379, 410

deposition of, 29formation of, 411

Mean demagnetizing field (MDF), 459, 465Median destructive field, 477Mendaiia Fracture Zone, 81, 122, 160, 164Mesocena elliptica Zone, 719Metal accumulation rates, 575

Site 319, 580Site 320, 585

Metal oxides, source of, 787Metalliferous sediments, 3, 559, 575

analytical procedures, 575Bauer Deep, 3, 33, 614, 803formation of, 19Site 320, 585Site 321, 585

Meteoritic sulfur, 383Mica, 389, 441, 616

formed during nonoxidative diagenesis, 405,412, 429

Micronodules, 615, 620, 621Microprobe procedures, 363Mid-Ocean Ridge Basalts (MORB), 264, 285, 301, 765Mineral chemistry, basalt, 218, 227-235, 764Mineral zoning, 280Models of sedimentation, Site 319, 581Mud-cross system, 3Multiple-regression analysis, 305, 306Muscovite, volcanic, 606Muskox Intrusion, 386Nannofossils

biostratigraphy, 705dissolution of, 715preservation of, 706

Site 319, 709Site 320, 711

Site 319, 707, 715Site 320, 711, 715Site 321, 711zonation, basis for, 715

Catinaster coalithus Zone, 715Ceratolithus primus Subzone, 715C. tricorniculatus Zone, 708Cyclicargolithus abisectus Subzone, 716Discoaster calcaris Zone, 29, 709

811

D. deflandrei Subzone, 716D. druggi Zone, 89, 711D. exilis Zone, 30, 709D. hamatus Zone,D. neohamatus Zone, 715D. quinqueramus Zone, 709, 715Gephyrocapsa oceanica Zone, 711Helicopontosphaera ampliaperta Zone, 714Sphenolithus ciperoensis Zone, 120, 711S. distentus Zone, 120, 711S. heteromorphus Zone, 30, 715, 783S. predistentus Zone, 120S. pseudoradians Zone, 711Triquetrorhabdulus carinatus Zone, 89, 711, 716

Natural remanent magnetization, 463,479,486, 501, 527direction, 481effect of alteration on, 433hard component, 524intensity, 459, 479, 502, 529, 764, 771inclinations, 768soft component, 524, 526stability, 479, 481

Nazca platebasement age, 278crust on, 19sediments, 3, 779magnetic anomaly 16, 81metalliferous sediments, 787motion of, 7, 29, 488, 521, 537, 776pillow basalts, 359radiolarian distribution, 713-714refraction data, 83tectonics, 803-807turbidites, 747

Nazca Ridge, 160Newark Group, 383Nonoxidative alteration of basalt, 463Nonoxidative diagenesis, 405, 412, 429

veins formed during, 407Nonoxidative formation of phillipsite, 421Oceanic basement, 173

crust, chemical leaching of, 433crust, radiometric ages of, 763

Ocean formation, 737Off-ridge volcanism, 3, 301, 306, 346Olivine, 227, 254, 270, 364, 417, 766Ommatartus antepenultimus Zone, 119, 713Opal, 799Opaque minerals, hematite, 270

in ocean floor basalts, 254, 381petrography of, 349, 362titanomagnetite, 269ulvospinel, 270

Operations summary, Leg 34, 3Organic carbon, 797Orthopyroxene, 606, 616Ostracodes, 737Oxidation processes, high temperature, 774Oxidative alteration of basalt, 405, 415, 463Oxidative diagenesis, 417

calcite formed during, 419of olivine, 417of titanomagnetite, 418

Oxygen isotopes, 386, 766Oxygen supply below sediment-water interface, 402Palagonite, 395, 616Paleobathymetry, 747Paleolatitudes, 537Paleomagnetic measurements, Site 319, 31, 34, 551

Site 321, 505Paleomagnetism, basalts, 513-532

sediments, 533-539Palisades Sill, 383Palynomorphs, 741, 743Pantelleritic volcanoes, 618Partial melting, 294, 301, 306Peru Current, solution effects of, 83Peru-Chile Trench, 164

as a barrier to sediments, 122Peruvian Neogene volcanic activity, 608Petrography, basalt, 189, 190, 764Phase chemistry of basalt, 198, 248, 278Phillipsite, 616

authigenic, 606, 619formation of, 414, 421

Physical properties, 767correlation with drilling results, 122methods used, 13Site 319, 30, 31Site 320, 90Site 321, 121

Pigeonites, 765Pillow basalts, Nazca plate, 359

prevalence in layer 2A, 3Plagioclase, 279, 765

description of, 273, 274in basalt, 264, 270, 273, 364volcanic, 605phase chemistry of, 199

Planktonic bloom, 631Planktonic diversity, 635Plate motion, 535

Nazca plate, 521, 537Potassium concentrations in basalt, 284Primary cooling, alteration minerals formed during, 399Primary minerals, 406Principal results in basement drilling, 3Pseudobrookite, 617Pyrite, 358, 377, 410

epigenetic, 381-384in basalt, 385

Pyroxene, description of, 273, 274, 275fractionation of, 274, 275in basalt, 248, 267, 271minor element chemistry, 199phase chemistry of, 199poikilitic, 274Site 319, 248Site 320, 250Site 321, 250

Pyrrhotite, 358Quartz, 617

in submarine basalts, 414Site 321, 799volcanic, 606

Radiolaria,

812

Site 321, 119Zonation

Amphiropalum ypsilon Zone, 713Anthocrytidium angulare Zone,Ommatartus antepenultimus Zone, 119, 713

Distribution of, Nazca plate 713-716Rare-earth-element patterns, 283

basalt, 763Rayleigh loops, 501, 503, 775Red semi-opaques (RSO), 612, 621Reducing conditions, 405Reflection profiles, correlation with drilling

results, Site 319, 32Site 320, 90Site 321, 122

Remagnetization of basalt, 523Remanent inclinations, 481Remanent magnetism, 481

stability of, 495Resistivity measurements, methods of, 549Rhizosolenia praebergonii Zone, 718Rutile, 617Sala-y-Gomez Fracture Zone, 160Sarmiento Ridge, 160Saturation magnetization, 466Scientific goals, 3Sclater age-depth curve, 741Sea-floor weathering, 338Seawater, alteration caused by, 286, 301, 305, 306, 399

depth of, 433Seawater oxidation of titanomagnetite, 433Sediment accumulation rates, 7, 560, 627, 789

Site 319, 30, 561Site 320, 89, 91Site 321, 116, 120, 122

Sediment-basalt contact, 443Site 319, 341Site 321, 462

Sediment classification system, 11Sediments, authigenic, 785

ferromanganoan, 560metalliferous, 3, 19, 33, 559, 575, 620, 785, 786,

787, 804Paleomagnetism of, 533-539Peru-Chile Trench as a barrier to, 122

Seismic survey, methods of, 163Sideromelane, 401Silica, hydrothermal addition of, 581Silicoflagellates, descriptive terms, 720

DictyochajDistephanus ratio, 715, 719Paleoecology of, 719Site 320, 715Site 321, 716Stratigraphy of, 719Taxonomy, 723-736zonation, basis for, 715

Dictyocha epiodon Zone 715, 720D. perlaevis delicata Zone, 719Distephanus boliviensis boliviensis Zone, 719Mesocena elliptica Zone

Site 319, Bauer Deep, 3, 19, 21, 57, 159, 190, 200,571, 618

absolute age of basement, 449

Ar40/Ar39 ages, 449, 743basalt, 27, 34, 190, 248, 270, 271, 273, 274, 279benthonic faunas, 635biostratigraphy, 29bottom-hole temperature and heat flow, 553carbonate-compensation depth, 33drilling program, 22foraminifera, 29geochemical measurements, 30interstitial water analyses, 625K-Ar dates for basalt, 445lithology, 25metal accumulation rates, 580metalliferous sediments, 577models of sedimentation, 581nannofossils, 707, 715paleomagnetic measurements, 31Paleomagnetism of basalt, 503petrography of basalt, 189, 764physical properties, 30, 31reflection profiles correlated with drilling, 32sediment accumulation rates, 80, 561sediment-basalt contact, 341sediments, 779site survey, 21sonobuoy survey, 21summary and conclusions, 33

Site 320, Nazca plate, 81-92background and objectives, 81Basalt, 87, 190, 191, 248benthonic faunas, 636biostratigraphy, 88diatoms, 715drilling program, 84foraminifera, 636geochemical measurements, 89, 90interstitial water analyses, 625lithology, 85magnetic reversal as reflected in sedi-

ments, 535metalliferous sediments, 575, 585nannofossils, 711, 715palynomorphs, 741petrography of basalt, 190, 764physical properties, 90reflection profiles correlated with drilling,

90sediment accumulation rates, 89, 91sediments, 779silicoflagellates, 715site survey, 83summary and conclusions, 90

Site 321, Nazca plate, 111-124background and objectives, 111basal sediment, 116, 117basalt, 117, 123, 248, 446, 449basalt-sediment contact, 117basement age, 763biostratigraphy, 119carbonate compensation depth, 116, 120clay mineralogy, 795diatoms, 718dinoflagellates, 742

813

drilling program, 113ebridians, 718foraminifera, 636, 637geochemical measurements, 120interstitial water analyses, 625lithology, 113magnetic anomaly patterns, 446metalliferous sediments, 585nannofossils, 711opal, 799organic carbon, 797Paleomagnetism, 505palynomorphs, 741petrography of basalt, 190, 764physical properties, 121, 122Radiolaria, 119reflection profiles correlated with drilling,

122sediment-basalt contact, 446sediment accumulation rates, 116, 120, 122sediments,silicoflagellates, 116site survey, 113summary and conclusions, 122

Slumping, 619Smectite, 386, 407, 617, 766, 388

formation of, 418Sonic velocity, decrease at sediment-basement

contact, 434Sphenolithus ciperoensis Zone, 120, 711

distentus Zone, 120, 711heteromorphus Zone (NN5), 30, 715, 783predistentus Zone (NP23), 120pseudoradians Zone, 711

Spreading rate, 168, 764East Pacific Rise, 561and chemistry of sediments, 561

Spreading ridge, basalts produced at, 763formation of basalt on, 767

Stillwater Complex, 383Sr87/Sr86 isotopic ratios, basalt, 763Strontium isotope ratios, 285Submarine basalts, alteration products of, 385

occurrence of birnessite in, 423occurrence of goethite in, 423occurrence of hematite in, 423occurrence of quartz on, 414occurrence of todorokite in, 423

Submarine volcanism, 560Sulfide globules, 364, 369, 368Sulfides, in basaltic rocks, 382

petrography of, 358primary, 359secondary, 359

Sulfide veins, 359Sulfur concentrations in basalt, 364, 375

isotope analyses of, 381, 385, 767solubility of, 377source of in basalts, 364, 378

Superparamagnetism, 503Stability index, 473, 477Susceptibility measurements, 479, 502

temperature dependence of, 507Talc, 409

Terrigenous components, 783Thermal demagnetization, 501Thermomagnetic analysis, 479

curve, 480, 490Tholeiites, low-olivine normative, 89Thorium concentrations on basalt, 343Titanomagnetites,, 462, 491, 764, 767

alteration of, 353, 358cation deficiency of, 358, 462, 523, 767, 773, 774

correlation with magnetic properties, 360degree of oxidation, 518opaque minerals, 269oxidative diagenesis of, 418petrography of, 349seawater oxidation of, 433

Todorokite, formation of, 415occurrence in submarine basalts, 423

Topography, effect on alteration, 767Trace elements, abundance of in Leg 34 basalts, 192,

239-243, 289, 293Triquetrorhabdulus carinatus Zone (NN1), 89, 711, 716Tuamotu Rise, 163Turbidites, 747Typical Oceanic Profile Sample (TOPS), 294Ulvospinel, 270Unconformity, angular, 122Uranium concentrations, basalt, 343, 352, 455Vein minerals, 767Verdun Formation, 747Vermiculite, 617Vertical component of magnetization, 483Viscous remanent magnetization, 467, 473, 475,

479-483, 527, 773Volcanic activity, Andean, 605, 611

Peruvian Neogene, 608Volcanic basement, alteration by seawater, 433Volcanic clinopyroxene, 606

K-feldspar, 605glass, 605, 783hornblende, 611muscovite, 606orthopyroxene, 606Plagioclase, 605quartz, 606zircon, 606

Volcanic material, 27Volcanism, 618

interplate, 301island arc, 618off-ridge, 3, 301, 305, 306, 346submarine, 560

Volcanoes, andesitic, 27pantelleritic, 618

Volcanogenic minerals, 619sediments, 783

Weathering, low temperature, 291, 433, 440See also Halmyrolysis

Weathering sea floor, 338Wharton Basin, 200X-ray fluorescence analyses, 239, 263X-ray diffraction analyses, 11, 386, 589Zeolites, 617, 619Zircon, 617

volcanic, 606

814