169 SUBJECT INDEX

169 SUBJECT INDEX
A-M

acoustic images, side-scan, Bent Hill, A:39, 158, 161
actinolite basalts, A:213 photograph, A:100, 218 photomicrograph, A:100 veins, A:216-217
albite, veins, A:216-217
alkali earths, pore water, A:115, 218, 278
alkali metals, pore water, A:116
alkalinity bacterial cells, B2:5 pore water, A:218, 279 vs. depth, A:115, 176, 220, 280 vs. magnesium, A:172
alkalis, pore water, A:218, 278
alkanes gas chromatographs, A:284 See also isoprenoid/alkane ratio
alteration chlorite, A:81 facies, A:265 geology, A:13 lithologic units, A:52 pillow lava, A:93-94
alteration, carbonate, lithologic units, A:209
alteration, chemical, sediments, A:221
alteration facies, hydrothermal alteration, A:267-268
altered rocks, photograph, A:100
aluminum immobility, A:99, 101 mass balance, A:98
aluminum oxide basalts, A:95 vs. depth, A:97 vs. loss on ignition, A:98 See also iron oxide-magnesium oxide-aluminum oxide plot
aluminum oxide/titanium oxide ratio, vs. zirconium/ titanium oxide ratio, A:102
ammonium bacterial cells, B2:8 pore water, A:171-175, 218, 277-281 sediments, B10:19 vs. depth, A:115, 176, 220, 276-278, 280; B2:8, 18 vs. magnesium number, A:118, 172, 178
amphibole basalts, A:213 lithologic units, A:267 photograph, A:100 photomicrograph, A:100 See also clinoamphibole; hornblende, basalts
amygdules, basalts, A:212-214
anatase, Deep Copper Zone, A:77
anhydrite alteration zones, A:82-84; B9:5 disseminated sulfides, A:270 dissolution, A:117 hydrothermal alteration, A:84 hydrothermal circulation, A:7-8 lithologic units, A:164-168; B10:15 massive sulfides, A:270 photograph, A:61, 75, 80-81, 85, 108, 166 pore water, A:115 rubble, A:168 sulfide banded/impregnated sandstone, A:76 sulfide mineralization, A:71 veins, A:75-76; B10:9
anhydrite, authigenic, photograph, A:80
anhydrite, coarse, photograph, A:71
anhydrite concretions, photograph, A:57
anhydrite nodules, photograph, A:57
anisotropy permeability, B8:4, 24 vs. depth, A:130
apatite, Deep Copper Zone, A:77
apparent age, thorium/uranium isotopes, B4:1-15
arsenic, hydrothermal alteration, A:39
authigenesis alteration zones, A:82; B10:15 clay mineralogy, B6:7

bacterial cells
bacterial profiles, sediments, B2:1-18
banding photomicrograph, A:72 See also colloform banding
barite clastic sulfides, A:59-61 disseminated sulfides, A:270 hydrothermal circulation, A:11 massive sulfides, A:270 rubble, A:168
barium clay mineralogy, B6:9 pore water, B1:2, 4 vs. depth, B1:12-13
basalts density and porosity, B7:5-6 electrical impedance, B8:5-8 geochemistry, A:96, 215-216 lithologic units, A:44-53 niobium-zirconium-yttrium plots, A:216 permeability, B8:3-5 petrography, A:90-93 petrology, A:271-272; B10:22 photograph, A:91-93, 214 photomicrograph, A:215 thermal conductivity, B8:8-10 transition to sediment, A:210-211 velocity, B7:7-8 whole-rock geochemistry, A:216
basalts, altered enrichment/depletion diagram, A:99 isocons, A:99 mass balance, A:99-101
basalts, diabasic, photomicrograph, A:215
basalts, microcrystalline, photograph, A:272
basalts, microgabbroic, photomicrograph, A:215
basalts, olivine-phyric, photomicrograph, A:271
basalts, plagioclase-clinopyroxene-olivine petrology, A:271 photomicrograph, A:271
basalts, plagioclase-clinopyroxene-phyric, petrology, A:212-214
basalts, plagioclase-phyric petrology, A:272 photomicrograph, A:271
basalts, porphyritic, mass balance, A:96, 98-99
basalts, pyroxene-phyric, photograph, A:92
base metals, leaching, A:102
basement interaction with sediments, A:221 mass balance, A:99
bathymetry Central Hill, A:262 drill intersections, A:271 geology, A:13 Middle Valley, A:38, 157 Site 1037, A:206
bedding, structural data, A:107-112
Bent Hill comparison with Dead Dog, A:160-162 geochronology, B4:1-15 hydrothermal circulation, A:9-11; B10:31 lithologic units, A:46-55 massive sulfides, B10:7-12 permeability and electrical and thermal properties, B8:1-42 site description, A:35-152; B10:3-4, 35 sulfide mineral chemistry and petrography, B5:1-34 vein networks, B9:1-25
Bent Hill Massive Sulfide, hydrothermal circulation, A:10-11, 37-38, 61-67
benz[a]anthracene, gas chromatographs, A:286
benzene sediments, A:282 vs. depth, A:285 See also ethane/benzene ratio
BHMS. See Bent Hill Massive Sulfide
biomass, microbial, sediments, B3:1-19
biostratigraphy Site 1035, A:38-39, 57-58 Site 1036, A:169 Site 1037, A:211-212 Site 1038, A:268 upper Quaternary, A:38-39
biotite, basalts, A:213
bioturbation Lithofacies A, A:54-56 photograph, A:61-62 sediment transition to basalt, A:210-211
bitumens gas chromatographs, A:120, 179-182, 224, 284, 286 geochemistry, A:119-120 sediments, A:178-182, 222-223, 225, 282, 284-287
black soot fluorescence, A:119 sediments, A:178-179, 222-223, 284
Blanco Fracture Zone, geology, A:11-13
blebs chalcopyrite, B9:5 lithologic units, A:208 photograph, A:74, 77
boron pore water, A:171-175, 218-219, 279 sediments, B10:19 vs. depth, A:116, 177, 220, 276-278, 280, 282 vs. magnesium, A:118, 172, 178
Bouma sequence, photograph, A:58
breccia clastic sulfides, A:59 lithologic units, A:52 massive sulfides, A:66 photograph, A:58
breccia, bedding-parallel hydraulic, photograph, A:110
breccia, hydraulic, structures, A:169
breccia, mud-clast lithologic units, A:165 photograph, A:60, 65, 108, 167
breccia, pyrrhotite-chalcopyrite, photograph, A:68
breccia, sulfide, photograph, A:67
brecciation, hydraulic, veins, A:75
bromide, vs. depth, B1:7-9
bromide/chloride ratio pore water, B1:3-4 vs. depth, B1:8-9
brookite, Deep Copper Zone, A:77
Brunhes Chron alteration, A:137-139 sediments, A:201, 232, 294
burrows, photograph, A:62, 80

calcimicrite, lithologic units, A:164
calcite alteration zones, A:82 basalts, A:213, 271 Deep Copper Zone, A:77 lithologic units, A:167 photograph, A:272 sediments, A:219, 221 veins, A:216-217
calcite, biogenic, lithologic units, A:164
calcite crystals, lithologic units, A:208
calcium clay mineralogy, B6:7, 9 hydrothermal component, A:281 mass balance, A:98 pore water, A:113-117, 171-175, 218, 274-281 sediments, B10:19 vs. chloride, A:279 vs. depth, A:112, 114-117, 176, 220, 276-278, 280, 282 vs. magnesium, A:118, 172, 174, 178 vs. strontium, A:114
calcium oxide basalts, A:95 clay minerals, B6:6, 23 vs. depth, A:97 vs. loss on ignition, A:98
caliper logs, vs. depth, A:132, 230
carbon bacterial cells, B2:6, 8 sediments, A:181-182 weight percentages, A:122-123, 226, 288-289
carbon, total sediments, A:120-121, 223, 287-288 vs. depth, A:124, 185, 227, 289-290 weight percentages, A:184, 226, 288-289
carbon, total inorganic sediments, A:121, 181-182 vs. depth, A:124, 185, 227, 289-290 weight percentages, A:184, 226, 288-289
carbon, total organic sediments, A:121, 181-182 vs. depth, A:124, 185, 227, 289-290 weight percentages, A:184, 226, 288-289
carbon/nitrogen ratio sediments, A:181-182 vs. depth, A:185, 290 weight percentages, A:122-123, 184, 226
carbon/sulfur ratio, weight percentages, A:122-123, 184, 226
carbon dioxide sediments, A:117, 119, 178, 222, 282 vs. depth, A:223, 284-285
carbon number maximum, bitumens, A:119-120, 179-181
carbon preference index bitumens, A:119-120 sediments, A:179-181, 223, 285-287 vs. depth, A:121, 183, 225, 287
carbonate nodules, pitted, photograph, A:166
carbonates alteration zones, A:82 See also calcimicrite; calcite; dolomicrite; dolomite
catagenesis, sediments, A:179-181, 285-287
cementation lithologic units, A:209 sediments, A:219, 221
cements, lithologic units, A:166-167
Central Hill hydrothermal alteration, A:259; B10:5-6, 20-21, 34 hydrothermal deposits, A:257-258 hydrothermal fluids, A:258-259 hydrothermal site, B6:1-24 site description, A:253-298 sulfide mineralization, A:259 tectonic activity, A:256-257 volcanic activity, A:257
cerium, mass balance, A:98
cesium, clay mineralogy, B6:7, 9
chalcopyrite backscattered electron image, B9:5, 19 hydrothermal circulation, A:11 massive sulfides, A:64-67 photograph, A:73-76, 80-81, 93; B9:5, 20 photomicrograph, A:68, 79; B5:16-18 precipitation within sedimentary pore spaces, B9:6, 22 sulfide mineralization, A:71 veins, A:75-76; B9:4-9, 16, 20 vs. depth, B5:15
chalcopyrite, massive fine-grained, photograph, A:68
chalcopyrite disease, massive sulfides, B5:6
chilled margins enrichment/depletion diagram, A:99 isocons, A:99 photograph, A:272 photomicrograph, A:95
chimneys, hydrothermal circulation, A:7-9
chloride bacterial cells, B2:7 pore water, A:113-117, 171-175, 218, 274-281; B1:3 sediments, B10:19 vs. calcium, A:279 vs. depth, A:114-116, 176, 220, 276-278, 280; B1:7-9; B2:8, 18 vs. magnesium, A:118, 172, 178 vs. potassium, A:279 vs. sodium, A:279 See also bromide/chloride ratio; sodium/chloride ratio
chlorite alteration, A:81, 86 alteration zones, A:82-84 basalts, A:213, 272 Deep Copper Zone, A:77-78 disseminated sulfides, A:270 geochemistry, B6:5-6, 14, 17 iron oxide-magnesium oxide-aluminum oxide plot, B6:18 lithologic units, A:267 photograph, A:92-93, 106-107, 272 photomicrograph, A:94-95, 271 pillow lava, A:93-94 rare earths, B6:20 sulfide mineralization, A:69 trace elements, B6:19 veins, A:75-76, 216-217 vs. depth, B6:14-17
chlorite, fibrous, photograph, A:82
chlorite, fibrous magnesium-rich, photomicrograph, A:86
chlorite, magnesium-rich hydrothermal alteration, A:259 photograph, A:80
chlorite/smectite mixed layer geochemistry, B6:7 vs. depth, B6:15, 17
chloritization alteration zones, A:82-84 clay mineralogy, B6:7 enrichment/depletion diagram, A:99 geochemistry, A:99 photograph, A:92-93, 272 photomicrograph, A:94-95 sills, A:91-93 sulfide banded/impregnated sandstone, A:76 veins, A:75-76
Chondrites Lithofacies A, A:56 photograph, A:62
Chron C1n alteration, A:137-139 sediments, A:201, 232
Circulation Obviation Retrofit Kit, hydrothermal circulation, A:13-14, 192-193
clasts lithologic units, A:167-168 structures, A:169 sulfides, A:67-68
clasts, mud, photograph, A:60, 65
clasts, pyrrhotite hydrothermal alteration, A:267-268 photograph, A:68
clasts, sulfide, photograph, A:67
clay clastic sulfides, A:59 hydrothermal circulation, A:11 lithologic units, A:167-168, 208-209
clay, blue-green, alteration zones, A:81-82
clay, hemipelagic, lithologic units, A:263
clay, silty Lithofacies A, A:54-56 lithologic units, A:52, 163-167 photograph, A:57, 60, 65-66, 211
clay mineralogy sediments, B6:22 vs. electrical impedance, B8:6-7, 28
clay minerals basalts, A:212-214 Lithofacies A, A:54-56 mineralogy and geochemistry, B6:1-24 photograph, A:70 pillow lava, A:94 See also chlorite; illite; smectite
claystone clastic sulfides, A:59; B10:13 lithologic units, A:165, 265
claystone, calcareous silty, lithologic units, A:209-210, 266
claystone, hemipelagic, photograph, A:66
claystone, indurated, photograph, A:85
claystone, silty, photograph, A:80
climbing ripples, photograph, A:62
clinoamphibole, sulfide banded/impregnated sandstone, A:76
clinopyroxene basalts, A:271 black crystals, A:212-214 mass balance, A:96, 98-99 photograph, A:92 sills, A:91-93
clinopyroxene, ophitic, photomicrograph, A:215
clinopyroxene, subophitic, photomicrograph, A:94, 271
Coiling Direction Zone 1, Site 1035, A:39
colloform banding, photomicrograph, A:72
Columbia River, sediments, A:219
compressional wave velocity sediments, A:130, 227, 289-292 vs. depth, A:130, 133, 229; B7:10-12 See also velocity
concretions alteration zones, A:82 See also anhydrite concretions; nodules
concretions, anhydrite lithologic units, A:52 photograph, A:57
concretions, carbonate hydrothermal alteration, A:84 lithologic units, A:52, 166-167
conductivity relationship between sample and fluid conductivities, B8:29 vs. formation factor, B8:42 vs. resistivity, B8:42 See also resistivity
consolidation, sediments, B8:10-12
convolute laminations photograph, A:62 sediment transition to basalt, A:210-211
copper basalts, A:96 clay minerals, B6:6, 24 Deep Copper Zone, A:76-78 depletion, A:99 enrichment, A:99 leaching, A:102 mass balance, A:98 massive sulfides, B5:5-6 sulfides, A:88-89 vs. depth, A:89, 97
copper-iron-zinc plots, sulfides, A:90
copper-lead-zinc plots, sulfides, A:90
CORK. See Circulation Obviation Retrofit Kit
correlation, sediments, A:264
cracks, sulfide deposition, B9:6-9
cross laminations Lithofacies B, A:56 lithologic units, A:166-167 photograph, A:60-61, 80; B9:6, 21; B10:11, 38 sills, A:90-93
crystals, authigenic, lithologic units, A:52
crystals, euhedral photograph, A:218 photomicrograph, A:79
cyclopropyls, community composition, B3:9

Dead Dog Mound comparison with Bent Hill, A:160-162 site description, A:153-203; B10:4-5
Dead Dog Vent Field geological cross-section, A:162 hydrothermal circulation, A:7-9; B10:4-5, 14-17, 32
Deep Copper Zone massive sulfides, B5:5-6 sulfides, A:76-78
deformation structures, photograph, A:61
deglaciation, lithologic units, A:163-165
density sediments, A:186-188, 225-227, 289-292; B7:4-6 vs. depth, A:125, 187, 190, 229, 291-294
density, grain sediments, A:127 vs. depth, A:128, 188, 228, 291, 293-294; B7:10-13 vs. formation factor, B8:6-7, 28 vs. permeability, B8:3-4, 23 vs. thermal conductivity, B8:8-9, 31
density, wet-bulk, vs. depth, A:228, 291, 293-294; B7:10-13
density logs vs. depth, A:132-133, 231 See also gamma ray-density-porosity logs
desiccation, exfoliative, photograph, A:214
diabase, hydrothermal circulation, A:10
diabase, ophitic, mass balance, A:96, 98-99
diagenesis photograph, A:55 pore water, A:175 sediments, A:179-181, 219, 221 See also alteration; authigenesis; catagenesis; cementation; recrystallization
diatoms, lithologic units, A:208
dissolution anhydrite, A:117 hydrothermal alteration, A:267-268 lithologic units, A:52 pore water, A:115
dolomicrite, photograph, A:55
dolomicrite, authigenic, lithologic units, A:164
dolomite alteration zones, A:82 lithologic units, A:164, 209; B10:15 sulfide mineralization, A:70
downhole measurements Site 1035, A:130-134 Site 1036, A:188-196 Site 1037, A:227-231 Site 1038, A:292-293

electrical impedance. See formation factor
epidote alteration zones, A:85 Deep Copper Zone, A:77 geochemistry, A:100-101 photograph, A:100 photomicrograph, A:95 veins, A:76
epidote, pistasitic, photomicrograph, A:100
erosion, lithofacies, A:57
Escanaba Trough bathymetry, B10:3 comparison with Middle Valley, B10:23-24 geochemistry, B1:1-16 hydrothermal circulation, A:7-16; B10:33 hydrothermal site, B6:1-24 physical properties, B7:1-19 site description, A:205-251, 253-298; B10:1-39
ethane sediments, A:117, 119 vs. depth, A:223, 284-285 See also methane/ethane ratio
ethane/benzene ratio, vs. depth, A:285
Eubacteria, community composition, B3:9
exfoliative desiccation, basalts, A:213
exhalations, hydrothermal circulation, A:7-9
exsolution, photomicrograph, A:68

Facies a, hydrothermal alteration, A:267
Facies c, hydrothermal alteration, A:267
Facies d, hydrothermal alteration, A:267
fatty acids active sulfide flange, B3:16 compared with other sediments, B3:17 microbial biomass, B3:1-19 mole percentages, B3:19
fault scarps, slumps, B10:21-22
fault zones, formation microscanner imagery, A:134
faults structural data, A:107-112 tectonics, A:256-257
faults, normal, hydrothermal circulation, A:9-10
faults, reverse, photograph, A:81
feeder zones hydrothermal circulation, A:73-78 massive sulfides, A:73-78, 270-271; B9:4-5; B10:7, 10-11, 36
feldspar geochemistry, B6:5-6, 14, 17 vs. depth, B6:14-17
fluid channels photograph, A:72 sulfide mineralization, A:71
fluid chemistry, pore water, B1:1-16
fluid flow alteration zones, A:87 permeability, B8:10-12 structural data, A:111 structures, B9:6-9
fluid inclusions, hydrothermal alteration, A:39
fluorescence, black soot, A:119
fluoride, vs. depth, B1:10
foraminifers lithologic units, A:208 preservation, A:268 zoning, A:212
foraminifers, planktonic stratigraphy, A:268 upper Quaternary, A:38-39 vs. depth, A:63
formation factor lithologic units, B8:5-8 vs. conductivity, B8:42 vs. frequency, B8:5-6, 27 vs. grain density, B8:6-7, 28 vs. permeability, B8:26 vs. pressure, B8:5, 25, 36-39
formation microscanner imagery logs, B8:18-19 vs. depth, A:133-136
fractionation, basalts, A:215-216
fractures basalts, A:213-214 formation microscanner imagery, A:134-135 photograph, A:61; B9:17 photomicrograph, A:71 sills, A:90-94 structural data, A:272-273 structures, A:216-217 sulfide deposition, B9:6-9 sulfides, A:39
frequency, vs. formation factor, B8:5-6, 27

galena mineralization, A:69 photomicrograph, B5:19 veins, A:75
gamma ray-density-porosity logs Site 1035, A:147-149 Site 1037, A:244-247
gamma ray-resistivity-sonic logs Site 1035, A:144-146 Site 1037, A:237-240
gamma rays correlation, A:128-130 sediments, A:126, 186-188, 225-227, 289-292 vs. depth, A:125, 127, 129, 187, 190, 229, 291-294
gamma-ray logs, vs. depth, A:132, 150-152, 230-231, 241-243, 248-251
gangue minerals, massive sulfides, A:270
gases, composition, A:118, 179, 222, 283-284
gases, volatile, sediments, A:117, 119, 175, 178, 221-222, 281-282
geochemistry basalts, A:96 clay minerals, B6:1-24 igneous rocks, A:95-102 pore water, B1:1-16 sedimentary rocks, A:101 sediments, B10:19-20 Site 1037, A:215-216 sulfides, A:87-89
geochemistry, inorganic Site 1035, A:112-117 Site 1036, A:169-175 Site 1037, A:217-221 Site 1038, A:273-281
geochemistry, organic Site 1035, A:117-123 Site 1036, A:175, 178-183 Site 1037, A:221-225 Site 1038, A:281-288
geochemistry, whole-rock, basalts, A:95-96, 216
geochronology, thorium-230/uranium-234 disequilibria, B4:1-15
geological setting Site 1035, A:37-38 Site 1036, A:155-157 Site 1037, A:206 Site 1038, A:255-259
geothermal gradient, vs. depth, A:195-196, 232-233, 295; B10:23
glacial/interglacial cycles, upper Quaternary, A:38-39
gold, hydrothermal circulation, A:9
Gorda Ridge geology, A:11-13 hydrothermal site, B6:1-24 physical properties, B7:1-19
gossan, structural data, A:108
graded bedding, photograph, A:61
grain size clay minerals, B6:21 igneous rocks, A:212
groundmass, photomicrograph, A:100
groundmass, cryptocrystalline, photomicrograph, A:271
groundmass, microcrystalline, photomicrograph, A:215
Guaymas Basin, fatty acids, B3:16-17
gypsum, rubble, A:168

halides, pore water, B1:1-4
halite, rubble, A:168
halos, photograph, A:88, 92, 218
heat flow, geology, A:12, 14
helium isotopes, hydrothermal alteration, A:39
hematite hydrothermal circulation, A:11 photomicrograph, A:79 sulfide mineralization, A:70 veins, A:75-76 vs. depth, B5:15
hemipelagites lithologic units, A:166-168, 209, 265-266 photograph, A:211
hexane, sediments, A:179-181, 222-223, 225
Holocene lithologic units, A:163-169, 207-208, 263, 265 sedimentation rates, A:268
Holocene/Pleistocene boundary biostratigraphy, A:58 depth, A:63, 170
hornblende, basalts, A:213
hornblende crystals, structures, A:216-217
hyaloclastite photograph, A:93 pillow lava, A:93-94 structural data, A:107-112
hydrocarbons, aliphatic, sediments, A:284-287
hydrocarbons, polynuclear aromatic, sediments, A:284-287
hydrocarbons, sediments, A:117, 119, 175, 178, 221-222, 281-282
hydrocarbons, thermogenic, sediments, A:287-289
hydrogen sulfide, sediments, A:117, 119, 178
hydrology, alteration zones, A:87
hydrothermal alteration basalts, A:213-214 boundaries, B10:15 clay mineralogy, B6:7-9 fractures, A:39 lithofacies, A:267-268 magnesium metasomatism, A:259 minerals, A:83 photograph, A:70-75, 77-82, 85-86 pore water, A:279 sediments, A:78-87 sulfides, A:78-87 veins, A:75 zones, A:78-87 See also alteration; chimneys; feeder zones; metasomatism
hydrothermal alteration, anhydrite, zones, A:82
hydrothermal alteration, blue-green clay, zones, A:81-82
hydrothermal alteration, carbonate, zones, A:82
hydrothermal alteration, chlorite, zones, A:82-84
hydrothermal alteration, epidote, zones, A:85
hydrothermal alteration, pyrite, zones, A:85-86
hydrothermal circulation Middle Valley, A:7-16 models, B9:8, 25
hydrothermal component chemical composition, A:281 near sulfide outcrops, A:281
hydrothermal deposits, sulfides, A:257-258
hydrothermal fluids composition, A:113, 173 dissolution, A:117 mineralization, A:258-259 pore water, A:175
hydrothermal systems, sulfides, A:41-42, 52-53
hyperthermophiles bacterial cells, B2:5-6 vs. depth, B2:14

igneous activity, geology, A:12; B10:22
igneous petrology Site 1035, A:89-102 Site 1037, A:212-214 Site 1038, A:271-272
igneous rocks grain size, A:212 petrography, A:90-94 vs. depth, A:91
illite geochemistry, B6:5-6, 14, 17 vs. depth, B6:14-17
ilmenite, bedding planes, A:90
impregnations, structural data, A:107-112
inclusions massive sulfides, B5:6; 9:5 mineralization, A:69 photomicrograph, B5:19
indenopyrene, gas chromatographs, A:286
index properties records, A:227 sediments, B7:1-19; B8:34-35 Site 1035, A:125-128 Site 1036, A:187 Site 1038, A:290 vs. depth, A:128, 187; B7:10
induration structural data, A:112 structures, A:169
interglacials. See glacial/interglacial cycles; Stage 5e interglacial assemblage zone
iodide pore water, B1:3 vs. depth, B1:7-9
iron. See copper-iron-zinc plots
iron monosulfide, lithologic units, A:209
iron oxide basalts, A:95, 216 clay minerals, B6:6, 23 vs. depth, A:97 vs. loss on ignition, A:98
iron oxide-magnesium oxide-aluminum oxide plot, chlorite, B6:18
iron oxyhydroxides, hydrothermal circulation, A:10
isocubanite clastic sulfides, A:59-61 hydrothermal circulation, A:11 massive sulfides, A:66, 269-270; B5:5-6 photograph, A:73-75, 88 photomicrograph, A:68, 79, 86; B5:16 veins, A:75-76; B9:4-9, 16 vs. depth, B5:15
isoprenoid/alkane ratio, bitumens, A:120
isoprenoids, sediments, A:223
isotopes, apparent age, B4:1-15

Juan de Fuca Ridge bacterial cells, B2:1-18 microbial biomass, B3:1-19 permeability and electrical and thermal properties, B8:1-42
Juan de Fuca Ridge N, physical properties, B7:1-19

kerogen, sediments, A:178-179
Klamath Mountains, sediments, A:219

laccoliths, mounds, A:256
laminations lithologic units, A:166-167, 208-210, 266 photograph, A:58, 211 structural data, A:107-112 See also convolute laminations; cross laminations
lanthanum, clay minerals, B6:6, 24
lava flows basalts, A:212-214 lithologic units, A:44-53 mass balance, A:99
lava tubes, basalt pillows, A:257
leaching, base metals, A:102
lead hydrothermal alteration, A:39 sulfides, A:88-89 vs. depth, A:89 See also copper-lead-zinc plots
lead isotopes, hydrothermal circulation, A:9
lipids microbial biomass, B3:1-19 See also phospholipids
lithium chemical alteration, A:221; B10:19 pore water, A:116, 171-175, 218, 274-281 vs. depth, A:116, 177, 220, 280, 282 vs. magnesium, A:118, 172, 178
lithofacies alteration, A:265 distribution, A:59 hydrothermal alteration, A:267-268 massive sulfides, A:67 sulfides, A:67-71 turbidites, A:53
Lithofacies A distribution, A:59 mudstone and siltstone, A:54-56
Lithofacies B distribution, A:59 siltstone and sandstone, A:56
lithologic units Central Hill, A:267 Site 1035, A:44-57 Site 1036, A:163-169 Site 1037, A:207-210 Site 1038, A:263-267 Unit I, A:44-53, 163-165, 207-208, 263 Unit II, A:44-53, 166-167, 208, 263, 265 Unit III, A:44-53, 59-61, 208, 265 Unit IV, A:167-168, 208-209, 265 Unit V, A:44-53, 61, 64, 66-72, 209, 265 Unit VI, A:44-53, 73-78, 209, 265-266 Unit VII, A:209-210, 266 Unit VIII, A:210, 266-267
lithostratigraphy Site 1035, A:44-51 Site 1036, A:163-169 Site 1037, A:207-211 Site 1038, A:263-268
lithostructural units, structural data, A:107-112
lobate structure, basalts, A:272
Logging Unit 1 sediments, A:131 well-logging, A:228
Logging Unit 2, sediments, A:131, 228, 230
Logging Unit 3, sediments, A:131, 230
Logging Unit 4, sediments, A:131-132, 230
Logging Unit 5, sediments, A:132-133, 230
Logging Unit 6, sediments, A:230-231
Logging Unit 7, sediments, A:231
logging units, sediments, A:131-133
loss on ignition basalts, A:95-96, 215-216 vs. depth, A:97 vs. magnesium number, A:98 vs. major oxides, A:98

magnesium chemical alteration, A:221 clay mineralogy, B6:9 hydrothermal circulation, A:9 hydrothermal component, A:281 mass balance, A:99 pore water, A:113-117, 171-175, 218, 274-281 vs. depth, A:112, 114-116, 176, 220, 276-278, 280, 282; B2:8, 18 vs. elements, A:118 vs. elements and compounds, A:172-173, 178
magnesium number basalts, A:95-96, 215-216 vs. depth, A:97 vs. loss on ignition, A:98 vs. titanium oxide, A:217
magnesium oxide basalts, A:95, 216 clay minerals, B6:6, 23 vs. depth, A:97 vs. loss on ignition, A:98 See also iron oxide-magnesium oxide-aluminum oxide plot
magnetic anomalies, hydrothermal circulation, A:10-11
magnetic declination, vs. depth, A:298
magnetic inclination, vs. depth, A:138-139, 200, 235, 298
magnetic intensity sediments, A:294-295 vs. depth, A:138-139, 200, 235, 298
magnetic susceptibility correlation, A:128-130 sediments, A:126, 186-188, 225-227, 289-292 vs. depth, A:126, 129, 138, 189-190, 229, 291-294
magnetic susceptibility, low-field, sediments, A:136
magnetic susceptibility anisotropy, sediments, A:136
magnetic susceptibility logs, vs. depth, A:266
magnetite hydrothermal circulation, A:11 massive sulfides, A:66; B5:5-6 photograph, A:73, 75 photomicrograph, A:271 veins, A:75-76 vs. depth, Site 856, B5:15 See also sphalerite-pyrrhotite-pyrite-magnetite
magnetite, heterogenous, sulfides, A:68-69
magnetostratigraphy, alteration, A:137-139
major elements basalts, A:95-96 clay mineralogy, B6:23
Mancos Shale, fatty acids, B3:17
manganese mass balance, A:98 pore water, B1:2, 4 vs. depth, B1:13
manganese oxide basalts, A:95 vs. depth, A:97
maps, hydrothermal circulation, A:16
marcasite clastic sulfides, A:59-61 hydrothermal circulation, A:11 massive sulfides, A:269-270 mineralization, A:69 photomicrograph, A:72 veins, A:75 vs. depth, B5:15 See also pyrite-marcasite
marker horizons, photograph, A:165
mass balance, alteration, A:96, 98-101
maturation bitumens, A:119-120 organic matter, A:178, 285-287 sediments, A:222-223, 225
Mendocino Fracture Zone, geology, A:11-13
mesophiles bacterial cells, B2:5-6 vs. depth, B2:14
mesostasis basalts, A:213-214, 271 photomicrograph, A:94, 271
metals mineralization, A:88 sources, A:89 zoning, A:89 See also alkali metals; base metals
metasomatism. See hydrothermal alteration
metasomatism, magnesium, hydrothermal alteration, A:259
methane bacterial cells, B2:8 sediments, A:117, 119, 178, 221-222, 281-282 vs. depth, A:119, 223, 284-285
methane/ethane ratio sediments, A:178, 221-222, 281-282 vs. depth, A:223, 284-285
methyl cyclopentane, gas chromatographs, A:284
methylnaphthalene, gas chromatographs, A:286
methylphenanthurene, gas chromatographs, A:286
mica, lithologic units, A:267
microbes, sediments, B3:1-19
microbiology Site 1035, A:123-125 Site 1036, A:183-184, 186 Site 1037, A:225 Site 1038, A:288-289
microlites, sills, A:92
microorganisms community composition, B3:9-12 microbial biomass, B3:1-19 sediments, A:123-125, 183-184, 186, 225, 288-289 See also bacterial cells; Eubacteria
microphenocrysts, photomicrograph, A:94
Middle Valley bacterial profiles, B2:1-18 bathymetry, B10:3, 30 comparison with Escanaba Trough, A:7-16; B10:23-24 hydrothermal field, B10:3, 39 massive sulfides, B10:7-17 microbial biomass, B3:1-19 site description, A:35-203; B10:1-39
mineral chemistry, massive sulfides, B5:1-34
mineralization stratigraphy, A:46-51 sulfides, A:58-89, 259; B10:10-11
mineralogy clay minerals, B6:1-24 hydrothermal alteration, A:83 massive sulfides, A:269-270
molds alteration zones, A:82 lithologic units, A:52 photograph, A:80
mounds, hydrothermal circulation, A:8-9
mud lithologic units, A:208-209 photograph, A:57
mud, hemipelagic, lithologic units, A:208-209, 263, 265
mud clasts clastic sulfides, A:59 photograph, A:60
mudstone Lithofacies A, A:54-56 lithologic units, A:265 photograph, A:61, 77, 100 sills, A:90-93

169 SUBJECT INDEX A-M

169 SUBJECT INDEX
A-M