APPENDIX 1

LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES AT SEAFLOOR

SPREADING CENTERS

The process of was hypothesized (Holmes, 1931; Hess, 1962; Dietz, 1961) and verified by application of the magnetic polarity-reversal time scale (Cox et al., 1963) to interpretation of the sequence of seafloor magnetic anomalies (Morley, unpublished manuscript; Vine and Matthews, 1963; Vine and Wilson, 1965; Pitman and Heirtzler, 1966) and dating of samples recovered in transects across the seafloor by the Deep Sea Drilling Project (Maxwell ~~., 1970).

Seafloor spreading centers were incorporated into the theory of plate tectonics as divergent plate boundaries where lithosphere ( and upper mantle) is generated by the process of seafloor spreading (McKenzie and Parker, 1967; Morgan, 1968; Le Pichon, 1968; Isacks ~ ale, 1968).

The existence of subseafloor hydrothermal convection systems in ocean basins was inferred from the presence of the components of such systems at oceanic ridges comprising magmatic heat sources to drive convection, seawater as a fluid medium, and fractured volcanic rocks as a permeable solid medium (Elder, 1965; Deffayes, 1970).

The hypersaline hydrothermal solutions in the vicinity of the Atlantis II Deep of the Red Sea appeared as an anomaly on the hydrographic data of the Swedish Deep Sea Expedition at a water sampling station of the research vessel ALBATROSS while transiting the Red Sea in 1948. (Bruneau ~ al., 1953). The anomaly was not recognized at that time. The Red Sea represents an early stage of opening of an ocean basin about a seafloor spreading center.

The combination of stratified high temperature and high salinity solutions ponded in certain basins along the axis of the Red Sea was recognized in hydrographic data of water sampling

771 772 LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES stations made by ships transiting the Red Sea between 1963 and 1965 during the International Indian Ocean Expedition (Charnock, 1964; Miller, 1964; Swallow and Crease, 1965).

Metalliferous sediments were found in certain basins along the axis of the Red Sea and their origin related to the metal-rich hypersaline hydrothermal solutions present (Miller et al., 1966; Hunt ~.!!.., 1967; Bischoff, 1969). --

Anomalously high contents of Fe, Mn, Cu, Cr, Ni, and Pb were identified in sediments of the and attributed to hydrothermal activity alternatively related to volcanism (Skornyakova, 1964; Arrhenius and Bonatti, 1965), or to exhala• tions from mantle-level magmatic processes (Bostrom and Peterson, 1966).

The first sample of solid hydrothermal material reported from an oceanic ridge was recovered in the form of a fractionated ferromanganese encrustation from a seamount located off the axis of the East Pacific Rise (Bonatti and Joensuu, 1966).

From the vantage point of Iceland, Palmason (1967) suggested that hydrothermal circulation may play a significant role in the distribution of oceanic heat flow, and Talwani et al. (1971) attributed low heat flow measured at the axis o~the Reykjanes Ridge to dissipation of heat by convective circulation of seawater.

An excess of the primordial inert isotope 3He was detected at mid-depth in the Pacific Ocean and attributed to mantle degassing at sites along the crest of the East Pacific Rise (Clarke et al., 1969), providing the basis for use of 3He as an index of hydr~ thermal discharge (Craig ~.!!.., 1975).

On the basis of the mineralogy of altered basalts, Hart (1970) suggested that much of the basalt-seawater interaction occurs by low-temperature reaction near the rock-seawater interface, but some basalt-seawater reaction takes place at depths of up to 5 km within the oceanic crust.

Recognition of the widespread occurrence of hydrated metamor• phosed oceanic crust and upper mantle led to realization that a large volume of water was required to react with the rocks (Melson et al., 1968; Miyashiro et al., 1971; Christensen, 1972); analysis Ci:f oxygen isotopes indicate~that a low 0 18 0 isotopic source such as seawater had interacted with the hydrated rocks (Muehlenbachs and Clayton, 1972; Spooner ~~., 1974).

Various lines of evidence from crustal sections interpreted as oceanic crust exposed on land (ophiolites) and in ocean basins LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES 773 were consolidated into a unified model for subseafloor metamor• phism, heat and mass transfer at seafloor spreading centers (Spooner and Fyfe, 1973).

The observation that theoretical values of conductive heat flow calculated from models of heat produced by the generation of lithosphere at oceanic ridges (McKenzie, 1967; Ie Pichon and Langseth, 1969; Sclater and Francheteau, 1970) exceeded the average measured values of conductive heat flow (Langseth and Von Herzen, 1970) led to the interpretation that the major portion of heat dissipation at oceanic ridges must be due to convective heat transfer by deeply circulating hydrothermal fluids (Lister, 1972).

The observed discrepency between theoretical and average measured conductive heat flow was used to estimate the global large magnitude of heat transfer by hydrothermal convection at seafloor spreading centers (Williams and Von Herzen, 1974; Wolery and Sleep, 1976).

A basal layer of metalliferous sediments was identified overlying basaltic basement in the Pacific Ocean Basin similar to the sediment forming at the crest of the East Pacific Rise, which demonstrated that metalliferous sediments have formed more or less continuously related to hydrothermal activity during seafloor spreading (von der Borch and Rex, 1970).

"Volcano-exhalative" and hydrogenous metal-bearing components of East Pacific Rise sediments were distinguished on the basis of radiogenically determined metal accumulation rates and distinctive lead isotopic composition (Bostrom, 1970; Bender ~~., 1971; Dasch ~~., 1971).

The observation that transition metals were depleted in the slowly cooled interior relative to the rapidly quenched exterior of extrusive basalts from the Mid-Atlantic Ridge was the basis for the inference that metals were mobilized from the interior by dissolution as chloride complexes in seawater that produced ore• forming hydrothermal solutions adequate to form metallic minerals observed at seafloor spreading centers (Corliss, 1971).

Discovery of the first active submarine hydrothermal field on an oceanic ridge in an open ocean basin by the NOAA Trans-Atlantic Geotraverse (TAG) project in 1972, the TAG Hydrothermal Field on the Mid-Atlantic Ridge, confirmed that hydrothermal processes could act more or less continuously from early to advanced stages in the opening of an ocean basin about a seafloor spreading center represented, respectively, by the Red Sea and the Atlantic Ocean (Rona, 1973; Rona and R. B. Scott, 1974; M. R. Scott et al., 1974; R. B. Scott ~~., 1974; Rona, 1980). -- 774 LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES

The first direct measurements of the magnitude and gradient of near-bottom water temperature anomalies with the characteris• tics of hydrothermal discharge at an oceanic ridge were made in 1973 at the TAG Hydrothermal Field on the Mid-Atlantic Ridge (Rona et al., 1974, 1975) and at the Galapagos Spreading Center (Williams ~.!!.., 1974).

Stockwork-type -iron sulfides were recovered from oceanic crust exposed in large-offset ridge-ridge transform fault segments of major fracture zones in the Atlantic Ocean (Bonatti et al., 1976) and Indian Ocean (Dmitriev et al., 1970; Rosanova and--• Baturin, 1976), and penetrated in a drillhole through the upper portion of oceanic crustal Layer 2 (Deep Sea Drilling Project Hole 504B south of the Costa Rica Rift; Anderson ~ a1., 1982).

Laboratory experiments reacting basalt with seawater in closed containers simulating pressures and temperatures of subsea• floor hydrothermal systems produced elemental exchanges analogous to those determined for oceanic crust from studies of basalt alteration and indicated chemical conditions for generating ore• forming hydrothermal solutions (Bischoff and Dickson, 1975; Hajash, 1975).

Simultaneous measurements of increased temperature and excess 3He in a near-bottom water sample recovered at the Galapagos Spreading Center in 1976 confirmed the existence of hydrothermal discharge from an oceanic ridge (Weiss ~.!!.., 1977).

The first direct observation of active submarine hydrothermal vents at an oceanic ridge and the discovery of a biological community associated with the vents was made diving with DSRV ALVIN at the Galapagos Spreading Center in 1977 where four groups of vents discharging hydrothermal solutLons at temperatures up to 17°C were investigated (Corliss et al., 1979). Clams in the vent biota were photographed by the Scripps Deep Tow instrumentation system (Lonsdale, 1977).

Global fluxes of certain elements extrapolated from their concentrations in dilute hydrothermal solutions sampled at the Galapagos Spreading Center were determined to equal or exceed input of those elements to the ocean by rivers transporting material derived from weathering of continents (Corliss et al., 1979; Edmond ~~., 1979). ------

The global magnitude of convective heat flux at seafloor spreading centers calculated at between 4.0 and 6.4 x 1019 cal y-1 from the discrepency between theoretical heat flow and average measured conductive heat flow (Williams and Von Herzen, 1974; Wolery and Sleep, 1976) was experimentally verified on the basis of extrapolation of the measured ratio between 3He and water LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES 775 temperature in hydrothermal effluent recovered at the Galapagos Spreading Center to the average oceanic flux of 3He (Jenkins ~ ~., 1978).

Investigation of biological communities at active hydro• thermal vents at the Galapagos Spreading Center and the East Pacific Rise at latitude 21°N revealed that bacteria capable of metabolizing hydrogen sulfide in the hydrothermal effluents were the primary producers at the base of the food chain, and that the chemosynthetic products are ultimately derived from internal heat energy of the Earth independent of photosynthesis (Corliss et a1., 1979; Jannasch and Wirsen, 1979; Karl, 1980). --

The chemosynthetic bacterial processes at oceanic hydro• thermal vents were proposed as an alternate to photosynthetic processes in shallow seas as an environment favorable for the evolution and maintenance of early forms of life (Corliss ~~., 1981).

Massive sulfide deposits in the form of mounds exposed on the seafloor were first directly observed and sampled at an oceanic ridge in 1978 by a team of French, American and Mexican scientists diving with the French submersible CYANA near the axis of the East Pacific Rise at latitude 21°N (CYAMEX Scientific Team, 1979).

Hydrothermal effluents with the properties of high• temperature (c. 350°C) end member solutions (acidic, reducing, metal-rich) predicted on the basis of extrapolation of mixing curves of low-temperature effluents (c. 10°C) previously sampled at the Galapagos Spreading Center (Edmond et a1., 1979) were recovered at "black smokers" discharging frommssi ve sulfide chimneys surmounting mounds at the axis of the East Pacific Rise at latitude 21°N by a team of scientists diving with DSRV ALVIN in 1979 (RISE Project Group, 1980) within hundreds of meters of the relict massive sulfide mounds observed in 1978 (CYAMEX Scientific Team, 1978).

The existence of high-temperature hydrothermal solutions (c. 300°C) at slow-spreading oceanic ridges comparable to such solutions at intermediate- to fast-spreading oceanic ridges was indicated by several lines of evidence from the Mid-Atlantic Ridge comprising temperature determinations from oxygen isotopes in hydrothermal quartz vugs (Rona et al., 1980), chemistry of fluid inclusions in quartz crystals (Delaney et a1., 1983), and the presence of sedimentary layers enriched-:Ln-nleta1s (Cu, Fe, Zn) derived from discharge of high-temperature solutions (Shearme et ~., 1983). -

Anomalies in conductive heat flow (Lawver and Williams, 1979) and in 3 He in near-bottom water (Lupton, 1979) led to the 776 LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES discovery of high-temperature hydrothermal activity associated with mineral deposits (Lonsdale et al., 1980) and hydrocarbons (Simoneit and Lonsdale, 1982) in~h~Guaymas Basin of the Gulf of California representative of the early stage of opening of an ocean basin about an intermediate-rate spreading center.

Sites at seafloor spreading centers in back-arc basins behind volcanic island arcs in the western Pacific were found to be loci of hydrothermal mineralization (Bertine and Keene, 1975; Bonatti et al., 1979) and of ongoing hydrothermal discharge (Horibe ~ al.-,-1982) •

A relict massive sulfide body apparently formed of coalesced mounds surmounted by chimneys with overall external dimensions comparable in size to economically interesting massive sulfide deposits in volcanogenic rocks on land was found at a site at the faulted margin of the axial zone of the Galapagos Spreading Center (Malahoff, 1982).

The occurrence of two-phase subseafloor hydrothermal convec- ~ tion systems involving separation liquid and vapor phases at oceanic water depths was inferred from the measurement of anoma• lous salinities in fluid inclusions within secondary alteration minerals in basalts recovered from certain sites on oceanic ridges (J~hl, 1975; Vanko and Batiza, 1982; Delaney et al., 1983; Cosens, 1983). --

The first drillhole to attain penetration of one kilometer into oceanic crust (Deep Sea Drilling Project Hole 504B on the intermediate spreading rate Costa Rica Rift) encountered a sheeted dike complex supporting the analogy between oceanic crust and certain ophiolites, and measured variations in permeability related to the horizontally layered structure of oceanic crust previously determined in seismic models (Anderson et al., 1982; Becker ~~., 1982). --

Observations of the distribution of metal-enriched sediments on the seafloor (Bostrom et al., 1969), and of geochemical tracers from hydrothermal sources~t-ndd-depth in the water column (3He; Lupton and Craig, 1981) support the interpretation that buoyant hydrothermal effluents at the crest of the East Pacific Rise discharge into a water mass characterized by higher temperature on an isopycnal surface at mid-depth in the water column (Reid, 1982) and dynamically drive that water mass (Stommel, 1982). LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES 777

REFERENCES

Anderson, R. N., Honnorez, J., Becker, K., Adamson, A. C., Alt, J. C., Emmermann, R., Kempton, P. D., Kinoshita, H., Laverne, C., Mottl, M. J., and Newmark, R. L., 1982, DSDP Hole 504B, the first reference section over 1 km through Layer 2 of the oceanic crust, Nature, 300:589-594.

Arrhenius, G. O. S., and Bonatti, E., 1965, Neptunism and volcanism in the ocean, in: "Progress in Oceanography," M. Sears (Editor), Pergamon~ress, London, 3:7-22.

Becker, K., Von Herzen, R. P., Francis, T. J. G., Anderson, R. N., Honnorez, J., Adamson, A. C., Alt, J. C., Emmermann, R., Kempton, P. D., Kinoshita, H., Laverne, C., Mottl, M. J., and Newmark, R. L., 1952, In-situ electrical resistivity and bulk porosity of the oceaniC:-crust, Costa Rica Rift, Nature, 300:594-598.

Bender, M., Broecker, W., Gornitz, V., Middel, U., Kay, R., Sun, S.-S, and Biscaye, P., 1971, r-~ochemistry of three cores from the East Pacific Rise, Earth hanet. Sci. Ltrs., 12:425-433.

Bertine, K. K., and Keene, J. B., 1975, Submarine barite-opal rocks of hydrothermal origin, Science, 18:150-152.

Bischoff, J. L., 1969, Red Sea geothermal brine deposits, in: "Hot Brines and Recent Heavy Metal Deposits of the Red Sea," E. T. Degens and D. A. Ross (Editors), 'Springer-Verlag, New York, pp. 348-401.

Bischoff, J. L., and Dickson, F. W., 1975, Seawater-basalt interaction at 200°C and 500 bars: implications for origin of seafloor heavy-metal deposits and regulation of seawater chemistry, Earth Planet. Sci. Ltrs., 25:385-397.

Bonatti, E., and Joensuu, 0., 1966, Deep-sea iron deposit from the South Pacific, Science, 154:643-645.

Bonatti, E., Kolla, V., Moore, W. S., and Stern, C., 1979, Metallogenesis in marginal basins: Fe-rich basal deposits from the Philippine Sea, Mar. Geol., 32:21-37.

Bostrom, K., 1970, Submarine volcanism as a source for iron, Earth Planet. Sci. Ltrs., 9:348-354.

Bostrom, K., and Peterson, M. N. A., 1966, Precipitates from hydrothermal exhalations on th~ East Pacific Rise, Econ. Geol., 61:1258-1265. 778 LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES

Bostrom, K., Peterson, M. N. A., Joensuu, 0., and Fisher, D. E., 1969, Aluminum-poor ferromanganoan sediments on active oceanic ridges, Jour. Geophys. Res., 74:3261-3270.

Bruneau, L., Jerlov, N. G., and Koczy, F. F., 1953, Physical and chemical methods, Swedish Deep-Sea Expedition Report, v. III, Physics and Chemistry, No.4, Appendix, Table I, Physical and Chemical Data, pp. XXIX, Station 254.

Charnock, H., 1964, Anomalous bottom water in the Red Sea, Nature, 203:591.

Christensen, N. L., 1972, The abundance of serpentinites in the oceanic crust, Jour. Geol., 80:709-719.

Corliss, J. B., 1971, The origin of metal-bearing submarine hydrothermal solutions, Jour. Geophys. Res., 76:8128-8138.

Corliss, J. B., Dymond, J., Gordon, L. I., Edmond, J. M., Von Herzen, R. P., Ballard, K., Green, K., Williams, D., Bainbridge, A., Crane, K., and van Andel, T. H., 1979, Submarine thermal springs on the Galapagos Rift, Science, 203:1073-1083.

Corliss, J. B., Baross, J. A., and Hoffman, S. E., 1981, Submarine hydrothermal systems: a probable site for the origin of life, Oceanologica Acta, Supplement to v. 4, pp. 59-69.

Cosens, B. A., 1983, Initiation and collapse of active circulation in a hydrothermal system at the Mid-Atlantic ridge, 23°N, Jour. Geophys. Res. (in press).

Cox, A., Doell, R. R., and Dalrymple, G. B., 1963, Radiometric dating of geomagnetic field reversals, Science, 140:1021-1023.

Craig, H., Clarke, W. B., and Beg, M. A., 1975, Excess 3He in the deep water on the East Pacific Rise, Earth Planet. Sci. Ltrs., 26:125-132.

CYAMEX Scientific Team (Francheteau, J., Needham, H. D., Choukroune, P., Juteau, T., Seguret, M., Ballard, R. D., FOX, P. J., Normark, W. R., Carranza, A., Cordoba, D., Guerrero, J., and Rangin, C.), 1979, Massive deep-sea-sulfide ore deposits discovered on the East Pacific Rise, Nature, 277:523-528.

Deffayes, K. S., 1970, The axial valley: a steady-state feature of the terrain, in: "The Megatectonics of Continents and Oceans," H. Johnson and B. L. Smith (Editors), Rutgers Univ. Press, Camden, New Jersey, pp. 194-222. LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES 779

Delaney, J. R., Mogk, D. W., and Mottl, M. J., 1983, Quartz• cemented, sulfide-bearing greenstone breccias from the Mid• Atlantic Ridge: samples of a high-temperature upflow zone, Science (in press).

Dietz, R. S., 1961, Continent and ocean basin evolution by spreading of the seafloor, Nature, 190:854-857.

Dmitriev, L. V., Barsukov, V. L., and Udintsev, G. B., 1970, Oceanic rift zones and problems of ore formation, Geokhim1ya, 8:937.

Edmond, J. M., Measures, C., McDuff, R. E., Chan, L. H., Collier, R., Grant, B., Gordon, L. I., and Corliss, J. B., 1979, Earth Planet. Sci. Ltrs., 46:1-18.

Elder, J. W., 1965, Physical processes in geothermal areas, in: "Terrestrial Heat Flow," W. H. K. Lee (Editor), Amer. Geophys. Union Geophys. Monograph Series, 8:211-239.

Hajash, A., 1975, Hydrothermal processes along mid-ocean ridges, Contrib. Mineral. Petrol., 53:205-226.

Hart, R. A., 1973, A model for chemical exchange in the basalt• seawater system of oceanic Layer 2, Canadian Jour. Earth Sci., 10:799-816.

Holmes, A., 1931, Radioactivity and earth movements, Geol. Soc. Glasgow Trans., 18:559-606.

Horibe, Y., Kim, K-R., and Craig, H., 1982, Deep ocean hydro• thermal vents in Mariana Trough, Fifth Int. Conf. on Isotope Geol., Nikko, Japan.

Hunt, J. M., Hayes, E. E., Degens, E. T., and Ross, D. A., 1967, Red Sea: detailed survey of hot brine areas, Science, 156:514-516.

Isacks, B., Oliver, J., and Sykes, L. R., 1968, Seismology and the new global tectonics, Jour. Geophys. Res., 73:5855-5899.

Jehl, V., 1975, Abstract in Fluid Inclusion Research, Proceedings of COFF!, E. Roedder, Editor, 8:75.

Jenkins, W. J., Edmond, J. M., and Corliss, J. B., 1978, Excess 3 He and 4 He in Galapagos submarine hydrothermal waters, Nature, 272:156-158. 780 LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES

Langseth, M. G., Jr., and Von Herzen, R. P., 1970, Heat flow through the floor of the world oceans, in: "The Sea," A. E. Maxwell (Editor), V. 4, Part I, Wiley-Interscience, New York, pp. 299-352.

Lawver, L. A., and Williams, D. L., 1979, Heat flow in the central Gulf of California, Jour. Geophys. Res., 84:3465-3478.

Le Pichon, X., 1968, Seafloor spreading and continental drift, Jour. Geophys. Res., 73:3661-3697.

Le Pichon, X., and Langseth, M. G., Jr., 1969, Heat-flow from the mid-ocean ridges and seafloor spreading, Tectonophysics, 8:319-344.

Lister, C. R. B., 1972, On the thermal balance of a mid-ocean ridge, Royal Astron. Soc. Geophys. Jour., 26:515-535.

Lonsdale, P. F., 1977, Clustering of suspension-feeding macro• benthos near abyssal hydrothermal vents at oceanic spreading centers, Deep-Sea Res., 24:857-863.

Lonsdale, P. F., Bischoff, J. L., Burns, V. M., Kastner, M., and Sweeney, R. E., 1980, A high-temperature hydrothermal deposit on the seabed at a Gulf of California spreading center, Earth Planet. Sci. Ltrs., 49:8-20. ---

Lupton, J. E., 1979, Helium-3 in the Guaymas Basin: evidence for injection of mantle volatiles in the Gulf of California, Jour. Geophys. Res., 84:7446-7452.

Malahoff, A., 1982, A comparison of the massive submarine poly• metallic sulfides of the Galapagos Rift with some continental deposits, Mar. Tech. Soc. Jour., 16:3:39-45.

Maxwell, A. E., Von Herzen, R. P., Hsu, K. J., Andrews, J. E., Saito, T., Percival, S. F., Milo, E. D., and Boyce, R. E., 1970, Deep-sea drilling in the South Atlantic, Science, 168:1047-1059.

McKenzie, D. P., 1967, Some remarks on heat flow and gravity anomalies, Jour. Geophys. Res., 72:6261-6273.

McKenzie, D. P., and Parker, R. L., 1967, The North Pacific: an example of tectonics on a sphere, Nature, 216:1276-1280.

Melson, W. G., Thompson, G., and van Andel, T. H., 1968, Volcanism and metamorphism in the Mid-Atlantic Ridge, 22°N, Jour. Geophys. Res., 73:5925-5941. -- LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES 781

Miller, A. R., 1964, Highest salinity in the world ocean? Nature, 203:590-591.

Miller, A. R., Densmore, C. D., Degens, E. T., Pocklington, R., and Jokela, A., 1966, Hot brines and recent iron deposits in deeps of the Red Sea, Geochim. Cosmochim. Acta, 30:341-359.

Miyashiro, A., Shido, F., and Ewing, M., 1971, Metamorphism in the Mid-Atlantic Ridge near 24° and 30 0 N, Royal Soc. Phil. Trans. (London), 268:589-603.

Morgan, W. J., 1968, Rises, trenches, great faults, and crustal blocks, Jour. Geophys. Res., 73:1959-1982.

Morley, L. W., 1963, An explanation of magnetic banding in ocean basins, in: "The Oceanic Lithosphere, The Sea," 1981, C. Emiliani--rEditor), v. 7, Wiley, New York, pp. 1717-1719.

Muehlenbachs, K., and Clayton, R. H., 1972, Oxygen isotope geochemistry of submarine greenstones, Canadian Jour. Earth Sci., 9:471-478.

Palmason, G., 1967, On heat flow in Iceland in relation to the Mid-Atlantic Ridge, in: "Iceland and Mid-Ocean Ridges," S. Bjornsson (Editor), Soc. Sci. Islandica, 38:111-117.

Pitman, W. C., III, and Heirtlzer, J. P., 1966, Magnetic anomalies over the Pacific-Antarctic Ridge, Science, 154:1164-1171.

Reid, J. L., 1982, Evidence of an effect of heat flux from the East Pacific Rise upon the characteristics of the mid-depth waters, Geophys. Res. Ltrs., 9:381-384.

RISE Project Group (Speiss, F. N., Macdonald, K. D., Atwater, T., Ballard, R., Carranza, A., Cordoba, D., Cox, C., Diaz Garcia, V. M., Francheteau, J., Guerrero, J., Hawkins, J., Haymon, R., Hessler, R., Juteau, T., Kastner, M., Larson, R., Luyendyk, B., Macdougall, J. D., Miller, S., Normark, W., Orcutt, J., and Rangin, C.), 1980, East Pacific Rise: hot springs and geophysical experiments, Science, 207:1421-1444.

Rona, P. A., 1973, New evidence for seabed resources from global tectonics, Ocean Management, 1:145-159.

Rona, P. A., and Scott, R. B., 1974, Convenors, Symposium: axial processes of the Mid-Atlantic Ridge, EOS, Trans. Amer. Geophys. Union, 55:292-295. ------782 LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES

Rona, P. A., McGregor, B. A., Betzer, P. R., and Krause, D. C., 1974, Anomalous water temperatures over Mid-Atlantic Ridge crest at 26°N, Amer. Geophys. Union Trans., EOS, 55:293.

Rona, P. A., McGregor, B. A., Betzer, P. R., Bolger, G. W., and Krause, D. C., 1975, Anomalous water temperatures over Mid• Atlantic Ridge crest at 26° north latitude, Deep-Sea Res., 22:611-618.

Rona, P. A., Bostrom, K., and Epstein, S., 1980, Hydrothermal quartz vug from the Mid-Atlantic Ridge, Geology, 8:569-572.

Rona, P. A., 1980, TAG Hydrothermal Field: Mid-Atlantic Ridge crest at latitude 26°N, Jour. Geo!. Soc. London, 137 :385-402.

Rozanova, T. V., and Baturin, G. N., 1971, Hydrothermal ore shows on the floor of the Indian Ocean, Oceanology, Academy of Sciences of USSR, translation by Amer. Geophys. Inst. 11(6) :847-879.

Sclater, J. G., and Francheteau, J., 1970, The implications of terrestrial heat-flow observations on current tectonic and geochemical models of the crust and upper mantle of the earth, Geophys. Jour., 20:509-542.

Scott, M. R., Scott, R. B., Rona, P. A., Butler, L. W., and Nalwalk, A. J., 1974, Rapidly accumulating manganese deposit from the median valley of the Mid-Atlantic Ridge, Geophys. Res. Ltrs., 1:355-358.

Scott, R. B., Rona, P. A., McGregor, B. A., and Scott, M. R., 1974, The TAG Hydrothermal Field, Nature, 251:301-302.

Simoneit, B. R. T., and Lonsdale, P. F., 1982, Hydrothermal petroleum in mineralized mounds at the seabed of Guaymas Basin, Nature, 295:198-202.

Shearme, S., Cronan, D. S., and Rona, P. A., 1983, Geochemistry of sediments from the TAG Hydrothermal Field, Mid-Atlantic Ridge at latitude 26°N, Mar. Geol. (in press).

Skornyakova, I. S., 1965, Dispersed iron and manganese in Pacific Ocean sediments, Inter. Geol. Rev., 7:2161-2174.

Spooner, E. T. C., and Fyfe, W. S., 1973, Sub-seafloor metamorphism, heat and mass transfer, Contrib. Mineral. Petrol., 42:287-304. LANDMARKS IN STUDIES OF HYDROTHERMAL PROCESSES 783

Spooner, E. T. C., Beckinsdale, R. D., Fyfe, W. S., and Smewing, J. D., 1974, ol8 enriched ophiolitic metabasic rocks from E. Liguria (Italy), Pindos (Greece), and Troodos (), Contrib. Mineral. Petrol., 47:41-74.

Stommel, H., 1982, Is the South Pacific helium-3 plume dynamically active? Earth Planet. Sci. Ltrs., 61:63-67.

Swallow, J. C., and Crease, J., 1965, Hot salty water at the bottom of the Red Sea, Nature, 205:165-166.

Talwani, M., Windisch, C. C., and Langseth, M. G., Jr., 1971, Reykjanes Ridge crest: a detailed geophysical study, Jour. Geophys. Res., 76:473-517.

Vanko, D. A., and Batiza, R., 1982, Plutonic rocks from the Mathematicians seamounts fossil ridge, East Pacific, EOS, Trans. Amer. Geophys. Union, 63:472.

Vine, F. J., and Matthews, D. H., 1963, Magnetic anomalies over ocean ridges, Nature, 199:947-949.

Vine, F. J., and Wilson, J. T., 1965, Magnetic anomalies over a young ocean ridge off Vancouver Island, Science, 150:485-489. von der Borch, C. C., and Rex, R. W., 1970, Amorphous iron oxide precipitates in sediments cored during Leg 5, Deep Sea Drilling Project, in: "Initial Reports of the Deep Sea Drilling Proj ect, "D. A. McManus et al. (Editors), v. 5, Government Print Office, Washington, D.C., pp. 541-544.

Weiss, R. F., Lonsdale, P., Lupton, J. E., Bainbridge, A. E., and Craig, H., 1977, Hydrothermal plumes in the Galapagos Rift, Nature, 269:600-603.

Williams, D. L., and Von Herzen, R. P., 1974, Heat loss from the Earth: new estimate, Geology, 2:327-328.

Williams, D. L., Von Herzen, R. P., Sclater, J. G., and Anderson, R. N., 1974, The Galapagos Spreading Center: lithospheric cooling and hydrothermal circulation, Royal Astron. Soc. Geophys. Jour., 38:587-608.

Wo!ery, T. J., and Sleep, N. H., 1976, Hydrothermal circulation and geochemical flux at mid-ocean ridges, Jour. Geol., 84:249- 275.

Photograph of authors and other participants at Cambridge University during the NATO Advanced Research Institute, "Hydrothermal Processes at Seafloor Spreading Centers," convened 5-8 April 1982.

Front Row: Left to Right

C. Lalou, D.S. Cronan, G. Thompson, K.C. Macdonald, R. Hekinian, P.A. Rona, T.H. van Andel, K.K. Turkenian, M.J. Mottl, J. Edmond

Middle Row: Left to Right

H. Craig, H.P. Taylor, Jr., B.J. Skinner, A.H.F. Robertson, V. Stef&nsson, R.D. Ballard, R.N. Anderson, J. Boyle, H. Jannasch

Back Row: Left to Right

J. Francheteau, C.R.B. Lister, B.E. Parsons, R.J. Rosenbauer, A. Fleet, F.J. Grassle, R. Hessler

Photograph of participants at Cambridge University during the NATO Advanced Research Institute, "Hydrothermal Processes at Seafloor Spreading Centers," convened 5-8 April 1982.

Front Row: Left to Right

H. Craig, D.S. Cronan, J. Francheteau, C.R.B. Lister, G. Thompson, K.C. Mcdonald, F. Machado, P.A. Rona, J. Honnorez, R.F. Dill, R.D. Ballard, N.A. Ostenso, R. Hessler, H. Thiel, F. Grassle

Second Row from Front: Left to Right

J. Verhoef, R. Whitmarsh, V. StefAnsson, B.E. Parsons. T. Juteau, G.A. Gross, H.P. Taylor, Jr., F. Albarede, H. Jannasch, E. Bonatti, K. Crane, J. Lydon, I.D. MacGregor, E.R. Oxburgh

Third Row from Front: Left to Right

R. Hekinian, B.J. Skinner, C. Mevel, L. Widenfalk, R. Bowen, H. Bougault, T.H. van Andel, J.R. Cann, R.J. Rosenbauer, D.T. Rickard, A. Malahoff, S.P. Varnavas, M.J. Mottl

Fourth Row from Front: Left to Right

K. Brooks, J.W. Elder, B. Stuart, K. Gunnesch, A. fleet, H.T. Papunen, A.H.F. Robertson, S.A. Moorby, J. Boyle, C. Lalou, V. Ittekkot

Top Row: Left to Right

K.K. Turekian, J. Hertogen, J.A. Pearce, J. Edmond, S.D. Scott, D.B. Duane, A.S. Laughton, H-W. Hubberton, R. Chesselet, R.L. Chase INDEX

Alteration: hydrothermal, Bacteria in hydrothermal fluids comparison of laboratory and (continued) field data, 212-216 aerobic microbial chemo• high-temperature, synthesis, 693-695 greenschist facies, 235, 497 chemosynthesis, 699-702, 736 mineral assemblages, East Pacific Rise 21°N, 234-241, 772 429-438 elemefttal fluxes, 239-252 Galapagos Spreading Center, Idaho batholith, 85 421-427 isotopic studies, 83 Galapagos Spreading Center and Krafla geothermal field, East Pacific Rise 21°N, Iceland, 305-315 411-449 laboratory experiments, gas (methane, hydrogen, carbon 177-197, 201-210 monoxide, nitrous oxide) mineral assemblages, 204-205, production, 412, 438- 216-218 445, 695-696 Oman ophiolite, 75, 83 microbial enrichments and relation between altered rocks isolations, 691-693 and solutions, 218 microbial transformations Reykjanes geothermal field, (experimental proce• Iceland, 295-300 dures), 690 Skaergaard intrusion, symbiosis of chemosynthetic Greenland, 75, 83, 89 bacteria with vent Alteration: low temperature, invertebrates, 696-698 chemical fluxes from deeper thermo-acidophilic bacteria, basement rocks, 252-255 703-704 elemental flux, 232-233 Basalt-seawater interaction, mineralogy, 231-232 169, 774 Authors present at NATO Advanced alteration mineralogy, 193 Research Institute, anhydrite, 193 787-788 elemental exchange, 173 evolved seawater, 190 Back arc basins, 776 hydrothermal flux, 266-267 Lau Basin, 509 laboratory experiments, Bacteria in hydrothermal fluids, 177-197 775

789 790 INDEX

Basalt-seawater interaction Chemical flux (continued) (continued) intermediate temperature flux laboratory versus field from flanks of oceanic conditions, 169-173 ridges, 256-260 pressure and temperature, low temperature flux from 179-181 deeper basement rocks, water-rock ratio, 172, 178, 252-255 199, 206-211 magnesium, 205, 230 Biology of hydrothermal vents, major constituents of river 28, 665-668, 774 and seawater, 227 bacteria, 680-704 mass balances, 229 chemosynthesis, 678, 679, water sampling procedure, 699-702, 728 370-371 evolution, 693-694, 700, 703 Convection (see Hydrothermal food sources, 720-728 convection system and food web (megafauna), 763-767 Heat Transfer) growth rates, 718-720 Cracking front hypothesis, 72 megafauna, 735-770 crack spacing, 155 metabolism, 720-723 field testing, 165, 337-338 methane, 695-696 physics, 141 microbial mats, 666, 683-690 sealing, 74 microbial transformation thermal boundary layer, 144 (experimental proce• dures), 690 Deep Sea Drilling Project, 5, 8, observational methods, 736-737 771 photosynthesis, 701 hole 417A, 256 relation of vent megafauna to hole 504B, 40, 282-285, 776 nonvent megafauna, hole 509B (Galapagos Mounds 761-763 Hydrothermal Field), settlement and ecological 515-516 stragegy, 714-718 leg 5, 476 symbiosis, 696-698, 702, 724, site 471 (sufide deposits), 763-767 509 water temperature, 755-757 sites, 457, 477, 478, 481,

Chemical flux, East Pacific Rise, 18, 24 dissolved constituents AMPH D2 Seamount hydrothermal delivered to oceans, 228 deposit, 505, 510 East Pacific Rise 21°N hydro• biology, 665-666, 678 thermal solutions, East Seamount, 512 371-389 gases (methane, hydrogen, high temperature flux from helium) in basalt, axes of mid-ocean 404-405, 411-449 ridges, 260-264, 363 gases (methane, hydrogen, hydrothermal, 66, 199, 214- helium) in hydrothermal 220, 225-278, 361-449 fluids, 391-409 hydrothermal flux, 241-252, 266 INDEX 791

East Pacific Rise (continued) Galapagos Spreading Center hydrothermal fluid chemistry, (continued) 206-207, 262, 369-389, manganese oxide, 513-515 776 massive sulfide deposits. 509, latitude 9°N, 60, 492 572, 644 latitude 13°N, 21, 32, 35, vent fields, 738 571-592. 666. 713 Gases in hydrothermal fluids, latitude 21°N. 33. 35. 178, argon, 365 207. 211. 260. 362. 492. carbon dioxide, 364 509. 512, 644, 701, 713 carbon monoxide. 364 mineralization. 494-497. 505, East Pacific Rise 21°N, 509, 566, 772, 776 391-409, 427-438 rare earth elements. 536-548 Galapagos Spreading Center, off-axis seamounts, 578-579 416-426 Rise Hydrothermal Field at helium. 364, 396-401, 412, 509 latitude 21°N. 38 hydrogen. 396-401 Electromagnetic measurements, krypton, 365 electromagnetic sounding. 39 methane. 364, 396-403, resistivity, 40. 284-285 453-457, 695-696 neon. 365 FAMOUS project,S, 18, 21, 22, nitrous oxide, 416-124 361. 514, 536. 548 sampling and analytical Ferromanganese deposits, methods, 392-395, 474-483, 496-498 412-416 accumulation rate, 513-515 xenon, 365 Apennines, Italy, 618 Gases in mid-ocean ridge banded iron formations basalt. (Algoma-type). 560, 562 methane, 403 distribution in ocean basins, helium, 403 506, 523-527 Gravity measurements at mid• Greece, 606-607 ocean ridges, 34, 62 hydrothermal origin, 518-520 Guaymas Basin, Gulf of rare earth elements (REE), California, 39 535-552 biology. 666. 680-702 Tethys Ocean (Mesozoic), geologic setting. 452 595-648 hydrothermal mineralization, 500-509, 572. 640 Galapagos Mounds Hydrothermal petroleum genesis and proto• Field, 4, 18, 513-516, kerogen degradation, 542, 549 451-471 Galapagos Spreading Center (Rift), 4, 7, 21, 207, Heat transfer, 340-341 211. 774 convective heat flux, 65, 72, biology, 665, 678, 681-690. 260, 362. 476, 773, 774 701. 712, 735-770 conductive heat flow, 37, 257 hydrothermal fluids. 260-261, thermal models, 40, 53, 55, 362, 369, 391-392. 62. 143. 257 411-449 792 INDEX

History of studies of hydro• Hydrothermal fluid (continued) thermal processes at temperature, 23, 211 seafloor spreading centers, 771-783 Iceland, Hydrothermal activity, 7 comparison of subaerial hydro• cracking front hypothesis, 72 thermal systems to sub• model high temperature subseafloor systems, venting, 79, 145 279-290, 316-317, seafloor spreading rate, 38 324-367 structure of magma chamber, 57 fracturing, 288 temperature of fluids, 23 geological relations, 110 Hydrothermal convection system: Grimsvotn geothermal area, subaerial, 334-337 comparison with subseafloor, heat flux, 340-350 279-290, 316-317 Heimaey 1973 eruption, 165, effect of topography, 328-334 337-338 global distributions, 323 hydrothermal mineralization, heat flux, 340-341 282, 327-328, 508 Iceland, 279-360 hydrothermal systems, 279-367 Idaho batholith, 86-89 isotopic systematics, 110 permeability, 285 Kolbeinsey Ridge, 371 relation to mineralization, Krafla area, 309-315, 343-349 492 Kverkfjoll geothermal area, Reykjanes geothermal field, 337 294-308 Reykjanes geothermal field, single versus two-phase 207, 210, 294-308 systems, 279-285, 324- Torfajokull geothermal area, 328, 495 337 Skaergaard, Greenland, 89-102 Idaho batholith, Hydrothermal convection system: hydrothermal circulation, subseafloor, 771 86-89 comparison with subaerial, isotopic systematics, 87-89 279-290, 316-360 Isotopic studies, duration, 666 applied to hydrothermal circu• effect of topography, 328-334 lation systems, 83-139, global distribution, 323 350, 363-364 heat flux, 340-341 carbon, 405-406, 453-459, 721 permeability, 285 helium, 364, 396-401, 412, single-phase system, 279-280 509, 772 two-phase system (boiling), hydrogen, 83, 396 281, 324-328, 776 lead, 364 Hydrothermal fluid, natural radionuclides applied chemistry, 77, 206, 211, 774, to growth rates of 775 clams, 718-720 Krafla geothermal field, neodymium, 364 Iceland, 309-315 oxygen, 83, 395-398, 428, 772 Reykjanes geothermal field, thorium, 516-518, 718 Iceland, 306-308 INDEX 793

Jabal at Tirf complex, Saudi Mid-Atlantic Ridge (continued) Arabia, FAMOUS area,S, 18, 21, 22, granophyres, 107 361, 514, 536, 548 hydrothermal circulation, 108 fracture zone mineralization, isotopic systematics, 104 509, 513-514 Juan de Fuca Ridge, 39, 548, 644 gases (methane, hydrogen, 667 helium) in basalt, 404 high-temperature hydrothermal Kolbeinsey Ridge, Iceland, 331 activity, 775 Iceland, 279-360 Magma chamber,S, 6, 7, 17, 19, latitude 45°N, 33 23, 29, 32, 35, 53 metalliferous sediments, 508 role in mineralization, 558, mineral deposits, 495 563 TAG Hydrothermal Field, 508, structure, 56, 60, 66, 80 511, 513-514, 519, 548- Magnetic reversal anomalies, 36, 549, 642-643, 773 771 Mineralization: hydrothermal, Maganese nodules, 474, 477-478 17, 263 association with palygorskite, Besshi-type ore, 500 514 classification of hydrothermal Baltic Sea, 477 metal deposits from Blake Plateau, 478 oceanic rifts, 491-500 East Seamount, 512 distribution of hydrothermal fossil, 478-482 deposits on ocean isotopic measurements, 482, basins, 506, 523-527 504 East Pacific Rise latitude MADCAP submarine volcano, 514 13°N, 579-591 Pacific, 478 En Kafala deposit, Afar, 479, rare earth elements (REE) , 482 483, 535-552 ferromanganese deposits, 474- redox capacities, 483 483, 496-498 Metalliferous sediments, Gulf of Aden, 500 accumulation rates, 475 Gulf of California, 500 basal layer, 773 Kuroko-type ore, 500 Bauer Deep, 499 Langban depOSit, Sweden, 479, composition, 507 482 East Pacific Rise, 478-481, massive sulfide deposits, 18, 773, 776 495-497 Indian Ocean, 478, 515-516 metalliferous sediments, 475 Nazca plate, 499 Mississippi Valley-type lead- Red Sea, 476-481 ore, 563 Santorini, 479 rare earth elements (REE), 483 Tethys Ocean (Mesozoic), redox capacities, 483 595-648 silicates, 497-498 Mid-Atlantic Ridge, I, 3, 8, 39 Tethys Ocean (Mesozoic) altered rocks, 200 595-648 boiling of hydrothermal fluids, 281 794 INDEX

Ophiolites, 6, 8, 17, 483, 772 Rare earth elements (continued) Anatalya, Turkey, 595-596, 648 indicator of hydrothermal or Baer-Bassit, Syria, 599 hydrogenous minerali• East Liguria, Italy, 550, 620, zation, 535-552 643 variability in ferromanganese Guleman, 599 deposits, 541 Hatay, 599 Red Sea, isotopic systematics, 117 comparison with Tethys Ocean Mamonia, Cyprus, 599 deposits, 640 Othris, Greece, 598, 606 gases (methane, helium) in hot plagiogranites, 131 brines, Samail ophiolite, 120, 566, Gulf of Aden, 500-513 595-596 manganese oxide deposit, 513 Troodos, Cyprus, 541, 566, metalliferous sediments and 595-596, 623-634 hot brines, 476, 478, Organic matter in sediments, 499, 509, 564, 701-702 detrital carbon (proto• rare earth elements, 550 kerogen), 459-467 Research vessels, fulvic and humic substances, CHALLENGER (HMS), 474 453-467 CHARCOT, JEAN (Research Guaymas Basin, 451-471 Vessel), 575 interstitial gas, 543-547 MELVILLE (Research Vessel), lipids, 457-463 460 Reykjanes Ridge, 2. 206-207, Participants in NATO Advanced 772 Research Institute, Rift valley of mid-ocean 785-786 ridges. 3, 6, 7 Permeability East Pacific Rise (see main convection, 149, 285 entry) -- cracking front hypothesis, Galapagos Spreading Center 72 (Rift) (see main entry) Nusselt number, 78, 152 Guaymas Basin, Gulf of permeability-depth function, California (see main 282 entry) -- Rahigh number, 78, 154 Iceland (see main entry) sealing, 74, 80 Juan de Fuca Ridge (see main Petroleum genesis and proto• entry) -- kerogen (detrital Kolbeinsey Ridge, Iceland (see carbon) degradation, main entry) -- analytical techniques, 452-453 Mid-Atlantic Ridge (see main related to hydrothermal acti• entry) -- vity in Guaymas Basin, Red Sea (see main entry) 451-471 relation to rate of seafloor spreading, 28, 30 Rare earth elements (REE), Reykjanes Ridge (see main 535-552 entry) -- fractionation in the marine RISE Hydrothermal Field, 38 environment, 537-540 INDEX 795

Samail ophiolite, Oman, Sulfide deposits (continued) isotopic systematics, 120 East Pacific Rise latitude mineralization, 566, 599, l3°N, 579-591 635-639 history of ideas of origin plagiogranites, 131 of volcanic hosted San Clemente fault, massive sulfide barite deposit, 509 deposits, 557-567, 775 Santorini Island, 550-551, 562 Kosaka Mine, Hokuroko Sea floor spreading rate, District, Japan, 561 relation to: Kuroko deposits, Japan, conductive heat flow, 37 561-562 geomorphology, 41 massive sulfide deposits, hydrothermal activity, 38 18, 495-497, 509, 776 magma chamber, 40, 66 stockwork sulfide deposits, magnetic anomaly pattern, 36 509, 774 microearthquakes, 33 overlapping spreading centers, TAG Hydrothermal Field, 508, 43 511, 513-514, 519, propagating rifts, 43 548-549, 642-643, 773 thermal models, 40 Tectonics of mid-ocean ridges, transform faults, 42 cracking fronts, 72 volcanic activity, 44 fractures, 236 Skaergaard intrusion, Greenland, microearthquake seismicity, 33 89 overlapping spreading centers, alkalic intrusions, 102 43 granophyres, 99 propagating rifts, 42 hydrothermal circulation, 97 rift valley, 3, 6, 7 oxygen isotopes, 90 transform faults, 6, 19 Structure of mid-ocean ridges, Tethys Ocean (Mesozoic), 595-648 gravity measurements, 34 continental rifting, 599-600 low velocity zone, 29 metallogenesis, 595-648 overlapping spreading centers, paleogeography, 596 43 passive margins, 608-612 propagating rifts, 42 seafloor spreading, 612 rift valley, 3, 6, 7 Tonga Kermadec ridge, seismic reflection and manganese oxide deposit refraction measurements, (hydrothermal), 512 29, 60 Troodos, Cyprus, Submersibles, comparison with present sea• ALVIN (deep submergence floor spreading centers, research vehicle), 281 644-645 369, 392, 404, 412-413, mineral deposits, 566, 628-634 666-668, 736, 774 rare earth elements in ferro• CYANA (diving saucer), 572- manganese deposits, 541 592, 666 seafloor spreading, 623-628 Sulfide deposits, Apennines, Italy, 613-618 Volcanic phenomena, cyclic activity, 7 796 INDEX

Volcanic phenomena (continued) flows, 23, 576 Tethys Ocean, 600-604 Volcano Island, 509, 562

Water-rock ratio, 172, 178, 199, 206-211 definition, 204 rock-dominated system, 182- 185, 187-190, 206 seawater-dominated system, 185-187, 206