@article {McDermott2015,
	title = {{Identification of sulfur sources and isotopic equilibria in submarine hot-springs using multiple sulfur isotopes}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {160},
	year = {2015},
	pages = {169{\textendash}187},
	abstract = {Multiple sulfur isotopes were measured in metal sulfide deposits, elemental sulfur, and aqueous hydrogen sulfide to constrain sulfur sources and the isotopic systematics of precipitation in seafloor hydrothermal vents. Areas studied include the Eastern Manus Basin and Lau Basin back-arc spreading centers and the unsedimented basalt-hosted Southern East Pacific Rise (SEPR) and sediment-hosted Guaymas Basin mid-ocean ridge spreading centers. Chalcopyrite and dissolved hydrogen sulfide (H2S) $δ$34S values range from -5.5{\textperthousand} to +5.6{\textperthousand} in Manus Basin samples, +2.4{\textperthousand} to +6.1{\textperthousand} in Lau Basin samples, and +3.7{\textperthousand} to +5.7{\textperthousand} in SEPR samples. Values of $δ$34S for cubic cubanite and H2S range from -1.4{\textperthousand} to +4.7{\textperthousand} in Guaymas Basin samples. Multiple sulfur isotope systematics in fluid-mineral pairs from the SEPR and Lau Basin show that crustal host rock and thermochemical reduction of seawater-derived dissolved sulfate (SO4) are the primary sources of sulfur in mid-ocean ridge and some back-arc systems. At PACMANUS and SuSu Knolls hydrothermal systems in the Eastern Manus Basin, a significant contribution of sulfur is derived from disproportionation of magmatic sulfur dioxide (SO2), while the remaining sulfur is derived from crustal host rocks and SO4 reduction. At the sedimented Guaymas Basin hydrothermal system, sulfur sources include crustal host rock, reduced seawater SO4, and biogenic sulfide. Vent fluid flow through fresher, less-mature sediment supplies an increased quantity of reactant organic compounds that may reduce 34S-enriched SO4, while fluid interaction with more highly-altered sediments results in H2S characterized by a small, but isotopically-significant input of 34S-depleted biogenic sulfides. Near-zero $Δ$33S values in all samples implicate the abiotic processes of SO4 reduction and leaching of host rock as the major contributors to sulfur content at a high temperature unsedimented mid-ocean ridge and at a back-arc system. $Δ$33S values indicate that SO2 disproportionation is an additional process that contributes sulfur to a different back-arc system and to acid spring-type hydrothermal fluid circulation. At the sedimented Guaymus Basin, near-zero $Δ$33S values are also observed, despite negative $δ$34S values that indicate inputs of biogenic pyrite for some samples. In contrast with previous studies reporting isotope disequilibrium between H2S and chalcopyrite, the $δ$34S values of chalcopyrite sampled from the inner 1{\textendash}2 mm of a chimney wall are within {\textpm}1{\textperthousand} of $δ$34S values for H2S in the paired vent fluid, suggesting equilibrium fluid-mineral sulfur isotope exchange at 300{\textendash}400 {\textdegree}C. Isotopic equilibrium between hydrothermal fluid H2S and precipitating chalcopyrite implies that sulfur isotopes in the chalcopyrite lining across a chimney wall may accurately record past hydrothermal activity.},
	keywords = {HOV Alvin (Human Occupied Vehicle), ROV Jason (Remotely Operated Vehicle)},
	doi = {10.1016/j.gca.2015.02.016},
	author = {McDermott, J M and Ono, S and Tivey, M K and Seewald, J S and Shanks, W C}
}
@article {German2010,
	title = {{Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise}},
	journal = {Proceedings of the National Academy of Sciences of the United States of America},
	volume = {107},
	number = {32},
	year = {2010},
	month = {aug},
	pages = {14020{\textendash}14025},
	abstract = {Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world{\textquoteright}s ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep hydrothermal vents along the similar to 110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at similar to 5,000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent types identified here and their relative geographic isolation make the MCR unique in the oceans. These new sites offer prospects for an expanded range of vent-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity-all in close proximity.},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0027-8424},
	doi = {10.1073/pnas.1009205107},
	author = {German, C R and Bowen, A and Coleman, M L and Honig, D L and Huber, J A and Jakuba, M V and Kinsey, J C and Kurz, M D and Leroy, S and McDermott, J M and de Lepinay, B M and Nakamura, K and Seewald, J S and Smith, J L and Sylva, S P and Van Dover, C L and Whitcomb, L L and Yoerger, D R}
}
@article {Cruse2010,
	title = {{Low-molecular weight hydrocarbons in vent fluids from the Main Endeavour Field, northern Juan de Fuca Ridge}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {74},
	number = {21},
	year = {2010},
	pages = {6126{\textendash}6140},
	abstract = {Despite its location on sediment-free basalt, vent fluids from the Main Endeavour Field (MEF) contain chemical species that indicate fluids have interacted with sediments during circulation. We report on the distribution and isotopic abundances of organic compounds (C1{\textendash}C3 alkanes and alkenes, benzene and toluene) in fluids collected from the Main Endeavour Field (MEF) in July, 2000, to understand the processes that regulate their abundances and characterize fluid sources. Aqueous organic compounds are derived from the thermal alteration of sedimentary organic matter and subsequently undergo further oxidation reactions during fluid flow. Fluid:sediment mass ratios calculated using $Σ$NH4 concentrations indicate that the sediments are distal to the MEF, resulting in a common reservoir of fluids for all of the vents. Following the generation from sediment alteration, aqueous organic compounds undergo secondary alteration reactions via a stepwise oxidation reaction mechanism. Alkane distributions and isotopic compositions indicate that organic compounds in MEF fluids have undergone a greater extent of alteration as compared to Middle Valley fluids, either due to differences in subsurface redox conditions or the residence time of fluids at subsurface conditions. The distributions of the aromatic compounds benzene and toluene are qualitatively consistent with the subsurface conditions indicated by equilibration of aqueous alkanes and alkanes. However, benzene and toluene do not achieve chemical equilibrium in the subsurface. Methane and CO2 also do not equilibrate chemically or isotopically at reaction zone temperatures, a likely result of an insufficient reaction time after addition of CO2 from magmatic sources during upflow. The organic geochemistry supports the assumption that the sediments with which MEF fluids interact has the same composition as sediments present in Middle Valley itself, and highlight differences in subsurface reaction zone conditions and fluid flow pathways at these two sites.},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2010.07.013},
	url = {http://dx.doi.org/10.1016/j.gca.2010.07.013},
	author = {Cruse, A M and Seewald, J S}
}
@inbook {Cruse2008,
	title = {{Hydrothermal fluid composition at Middle Valley, northern Juan de Fuca Ridge: temporal and spatial variability}},
	booktitle = {Magma to microbe : modeling hydrothermal processes at ocean spreading centers},
	series = {Geophysical Monograph},
	number = {178},
	year = {2008},
	pages = {145{\textendash}166},
	publisher = {American Geophysical Union},
	organization = {American Geophysical Union},
	address = {Washington, DC},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	isbn = {0875904432},
	doi = {10.1029/178GM08},
	url = {http://dx.doi.org/10.1029/178GM08},
	author = {Cruse, A M and Seewald, J S and Saccocia, P J and Zierenberg, R},
	editor = {Lowell, R P}
}
@article {Cruse2006,
	title = {{Geochemistry of low-molecular weight hydrocarbons in hydrothermal fluids from Middle Valley, northern Juan de Fuca Ridge}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {70},
	number = {8},
	year = {2006},
	pages = {2073{\textendash}2092},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2006.01.015},
	url = {http://dx.doi.org/10.1016/j.gca.2006.01.015},
	author = {Cruse, A M and Seewald, J S}
}
@article {Seewald2003,
	title = {{Aqueous volatiles in hydrothermal fluids from the Main Endeavour Field, northern Juan de Fuca ridge: Temporal variability following earthquake activity}},
	journal = {Earth and Planetary Science Letters},
	volume = {216},
	number = {4},
	year = {2003},
	pages = {575{\textendash}590},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0012-821X},
	doi = {10.1016/S0012-821X(03)00543-0},
	url = {http://dx.doi.org/10.1016/S0012-821X(03)00543-0},
	author = {Seewald, J S and Cruse, A M and Saccocia, P J}
}
@article {Seyfried2003,
	title = {{Chemistry of hydrothermal vent fluids from the Main Endeavour Field, northern Juan de Fuca Ridge: Geochemical controls in the aftermath of June 1999 seismic events}},
	journal = {Journal of Geophysical Research},
	volume = {108},
	number = {B9},
	year = {2003},
	pages = {Article no. 2429},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0148-0227},
	doi = {10.1029/2002JB001957},
	url = {http://dx.doi.org/10.1029/2002JB001957},
	author = {Seyfried, W E and Seewald, J S and Berndt, M E and Ding, K and Foustoukos, D}
}
