Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 188.Diversity of Hydrothermal Systems on Slow Spreading Ocean Ridges presents a multidisciplinary overview of the remarkable emerging diversity of hydrothermal systems on slow spreading ocean ridges in the Atlantic, Indian, and Arctic oceans. When hydrothermal systems were first found on the East Pacific Rise and other Pacific Ocean ridges beginning in the late 1970s, the community consensus held that the magma delivery rate of intermediate to fast spreading was necessary to support black smoker-type high-temperature systems and associated chemosynthetic ecosystems and polymetallic sulfide deposits. Contrary to that consensus, hydrothermal systems not only occur on slow spreading ocean ridges but, as reported in this volume, are generally larger, exhibit different chemosynthetic ecosystems, produce larger mineral deposits, and occur in a much greater diversity of geologic settings than those systems in the Pacific. The full diversity of hydrothermal systems on slow spreading ocean ridges, reflected in the contributions to this volume, is only now emerging and opens an exciting new frontier for ocean ridge exploration, including Processes of heat and chemical transfer from the Earth's mantle and crust via slow spreading ocean ridges to the oceans The major role of detachment faulting linking crust and mantle in hydrothermal circulation Chemical reaction products of mantle involvement including serpentinization, natural hydrogen, abiotic methane, and hydrocarbon synthesis Generation of large polymetallic sulfide deposits hosted in ocean crust and mantle Chemosynthetic vent communities hosted in the diverse settings The readership for this volume will include schools, universities, government laboratories, and scientific societies in developed and developing nations, including over 150 nations that have ratified the United Nations Convention on the Law of the Sea.

Published by the American Geophysical Union as part of the Geophysical Monograph Series, Volume 188.Diversity of Hydrothermal Systems on Slow Spreading Ocean Ridges presents a multidisciplinary overview of the remarkable emerging diversity of hydrothermal systems on slow spreading ocean ridges in the Atlantic, Indian, and Arctic oceans. When hydrothermal systems were first found on the East Pacific Rise and other Pacific Ocean ridges beginning in the late 1970s, the community consensus held that the magma delivery rate of intermediate to fast spreading was necessary to support black smoker-type high-temperature systems and associated chemosynthetic ecosystems and polymetallic sulfide deposits. Contrary to that consensus, hydrothermal systems not only occur on slow spreading ocean ridges but, as reported in this volume, are generally larger, exhibit different chemosynthetic ecosystems, produce larger mineral deposits, and occur in a much greater diversity of geologic settings than those systems in the Pacific. The full diversity of hydrothermal systems on slow spreading ocean ridges, reflected in the contributions to this volume, is only now emerging and opens an exciting new frontier for ocean ridge exploration, including* Processes of heat and chemical transfer from the Earth's mantle and crust via slow spreading ocean ridges to the oceans* The major role of detachment faulting linking crust and mantle in hydrothermal circulation* Chemical reaction products of mantle involvement including serpentinization, natural hydrogen, abiotic methane, and hydrocarbon synthesis* Generation of large polymetallic sulfide deposits hosted in ocean crust and mantle* Chemosynthetic vent communities hosted in the diverse settingsThe readership for this volume will include schools, universities, government laboratories, and scientific societies in developed and developing nations, including over 150 nations that have ratified the United Nations Convention on the Law of the Sea.

PrefacePeter A. Rona, Colin W. Devey, Jérôme Dyment, andBramley J. Murton viiDiversity of Hydrothermal Systems on Slow Spreading OceanRidges: IntroductionPeter A. Rona, Colin W. Devey, Jérôme Dyment, andBramley J. Murton 1Emerging Diversity of Hydrothermal Systems on Slow SpreadingOcean RidgesPeter A. Rona 5Hydrothermal Circulation at Slow Spreading Ridges: Analysis ofHeat Sources and Heat Transfer ProcessesRobert P. Lowell 11Chemical Signatures From Hydrothermal Venting on Slow SpreadingRidgesHenrietta N. Edmonds 27The Magnetic Signature of Hydrothermal Systems in Slow SpreadingEnvironmentsMaurice A. Tivey and Jérôme Dyment 43Hydrothermal Activity at the Arctic Mid-Ocean RidgesRolf B. Pedersen, Ingunn H. Thorseth, Tor Eivind Nygård,Marvin D. Lilley, and Deborah S. Kelley 67Implications of the Iceland Deep Drilling Project for ImprovingUnderstanding of Hydrothermal Processes at Slow Spreading Mid-OceanRidgesWilfred A. Elders and Gudmundur ÓmarFridleifsson 91Crustal Structure, Magma Chamber, and Faulting Beneath the LuckyStrike Hydrothermal Vent FieldWayne C. Crawford, Satish C. Singh, Tim Seher, Violaine Combier,Doga Dusunur, and Mathilde Cannat 113The Relationships Between Volcanism, Tectonism, and HydrothermalActivity on the Southern Equatorial Mid-Atlantic RidgeC. W. Devey, C. R. German, K. M. Haase, K. S. Lackschewitz, B.Melchert, and D. P. Connelly 133The Ultraslow Spreading Southwest Indian RidgeDaniel Sauter and Mathilde Cannat 153Deformation and Alteration Associated With Oceanic andContinental Detachment Fault Systems: Are They Similar?Barbara E. John and Michael J. Cheadle 175Detachment Fault Control on Hydrothermal Circulation Systems:Interpreting the Subsurface Beneath the TAG Hydrothermal FieldUsing the Isotopic and Geological Evolution of Oceanic CoreComplexes in the AtlanticAndrew M. McCaig, Adélie Delacour, Anthony E. Fallick,Teddy Castelain, and Gretchen L. Früh-Green 207Serpentinization and Associated Hydrogen and Methane Fluxes atSlow Spreading RidgesMathilde Cannat, Fabrice Fontaine, and Javier Escartín241High Production and Fluxes of H2 and CH4 and Evidence of AbioticHydrocarbon Synthesis by Serpentinization in Ultramafic-HostedHydrothermal Systems on the Mid-Atlantic RidgeJean Luc Charlou, Jean Pierre Donval, Cécile Konn,Hélène Ondréas, Yves Fouquet, PhilippeJean-Baptiste, and Elise Fourré 265Phase Equilibria Controls on the Chemistry of Vent Fluids FromHydrothermal Systems on Slow Spreading Ridges: Reactivity ofPlagioclase and Olivine Solid Solutions and the pH-SilicaConnectionW. E. Seyfried Jr., Nicholas Pester, and Qi Fu 297Geodiversity of Hydrothermal Processes Along the Mid-AtlanticRidge and Ultramafic-Hosted Mineralization: A New Type of OceanicCu-Zn-Co-Au Volcanogenic Massive Sulfide DepositYves Fouquet, Pierre Cambon, Joël Etoubleau, Jean LucCharlou, Hélène Ondréas, Fernando J. A. S. Barriga,Georgy Cherkashov, Tatiana Semkova, Irina Poroshina, M. Bohn, JeanPierre Donval, Katell Henry, Pamela Murphy, and Olivier Rouxel321Hydrothermal Systems: A Decade of Discovery in Slow SpreadingEnvironmentsDeborah S. Kelley and Timothy M. Shank 369Chemosynthetic Communities and Biogeochemical Energy PathwaysAlong the Mid-Atlantic Ridge: The Case of BathymodiolusAzoricusN. Le Bris and S. Duperron 409Index 431