@article {Neira2016,
	title = {{Cross-hole tracer experiment reveals rapid fluid flow and low effective porosity in the upper oceanic crust}},
	journal = {Earth and Planetary Science Letters},
	volume = {450},
	year = {2016},
	pages = {355{\textendash}365},
	abstract = {Numerous field, laboratory, and modeling studies have explored the flows of fluid, heat, and solutes during seafloor hydrothermal circulation, but it has been challenging to determine transport rates and flow directions within natural systems. Here we present results from the first cross-hole tracer experiment in the upper oceanic crust, using four subseafloor borehole observatories equipped with autonomous samplers to track the transport of a dissolved tracer (sulfur hexafluoride, SF6) injected into a ridge-flank hydrothermal system. During the first three years after tracer injection, SF6 was transported both north and south through the basaltic aquifer. The observed tracer transport rate of \~{}2{\textendash}3 m/day is orders of magnitude greater than bulk rates of flow inferred from thermal and chemical observations and calculated with coupled fluid-heat flow simulations. Taken together, these results suggest that the effective porosity of the upper volcanic crust through which much tracer was transported is {\textless}1{\%}, with fluid flowing rapidly along a few well-connected channels. This is consistent with the heterogeneous (layered, faulted, and/or fractured) nature of the volcanic upper oceanic crust.},
	keywords = {HOV Alvin (Human Occupied Vehicle), ROV Jason (Remotely Operated Vehicle)},
	doi = {10.1016/j.epsl.2016.06.048},
	author = {Neira, N M and Clark, J F and Fisher, A T and Wheat, C G and Haymon, R M and Becker, K}
}
@article {Cowen2012,
	title = {{Advanced instrument system for real-time and time-series microbial geochemical sampling of the deep (basaltic) crustal biosphere}},
	journal = {Deep-Sea Research. Part I: Oceanographic Research Papers},
	volume = {61},
	year = {2012},
	pages = {43{\textendash}56},
	abstract = {Integrated Ocean Drilling Program borehole CORK (Circulation Obviation Retrofit Kit) observatories provide long-term access to hydrothermal fluids circulating within the basaltic crust (basement), providing invaluable opportunities to study the deep biosphere. We describe the design and application parameters of the GeoMICROBE instrumented sled, an autonomous sensor and fluid sampling system. The GeoMICROBE system couples with CORK fluid delivery lines to draw large volumes of fluids from crustal aquifers to the seafloor. These fluids pass a series of in-line sensors and an in situ filtration and collection system. GeoMICROBE{\textquoteright}s major components include a primary valve manifold system, a positive displacement primary pump, sensors (e.g., fluid flow rate, temperature, dissolved O2, electrochemistry-voltammetry analyzer), a 48-port in situ filtration and fluid collection system, computerized controller, seven 24~V{\textendash}40~A batteries and wet-mateable (ODI) communications with submersibles. This constantly evolving system has been successfully connected to IODP Hole 1301A on the eastern flank of the Juan de Fuca Ridge. Also described here is a mobile pumping system (MPS), which possesses many of the same components as the GeoMICROBE (e.g., pump, sensors, controller), but is directly powered and controlled in real time via submersible operations; the MPS has been employed repeatedly to collect pristine basement fluids for a variety of geochemical and microbial studies.},
	keywords = {HOV Alvin (Human Occupied Vehicle), ROV Jason (Remotely Operated Vehicle)},
	issn = {0967-0637},
	doi = {10.1016/j.dsr.2011.11.004},
	url = {http://dx.doi.org/10.1016/j.dsr.2011.11.004},
	author = {Cowen, J P and Copson, D A and Jolly, J and Hsieh, C -C and Lin, H -T and Glazer, B T and Wheat, C G}
}
@article {Mottl2011,
	title = {{Chemistry of hot springs along the Eastern Lau Spreading Center}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {75},
	number = {4},
	year = {2011},
	pages = {1013{\textendash}1038},
	abstract = {The Eastern Lau Spreading Center (ELSC) is the southernmost part of the back-arc spreading axis in the Lau Basin, west of the Tonga trench and the active Tofua volcanic arc. Over its 397-km length it exhibits large and systematic changes in spreading rate, magmatic/tectonic processes, and proximity to the volcanic arc. In 2005, we collected 81 samples of vent water from six hydrothermal fields along the ELSC. The chemistry of these waters varies both within and between vent fields, in response to changes in substrate composition, temperature and pressure, pH, water/rock ratio, and input from magmatic gases and subducted sediment. Hot-spring temperatures range from 229{\textdegree} to 363~{\textdegree}C at the five northernmost fields, with a general decrease to the south that is reversed at the Mariner field. The southernmost field, Vai Lili, emitted water at up to 334~{\textdegree}C in 1989 but had a maximum venting temperature of only 121~{\textdegree}C in 2005, due to waning activity and admixture of bottom seawater into the subseafloor plumbing system. Chloride varies both within fields and from one field to another, from a low of 528~mmol/kg to a high of 656~mmol/kg, and may be enriched by phase separation and/or leaching of Cl from the rock. Concentrations of the soluble elements K, Rb, Cs, and B likewise increase southward as the volcanic substrate becomes more silica-rich, especially on the Valu Fa Ridge. Iodine and $δ$7Li increase southward, and $δ$11B decreases as B increases, apparently in response to increased input from subducted sediment as the arc is approached. Species that decrease southward as temperature falls are Si, H2S, Li, Na/Cl, Fe, Mn, and 87Sr/86Sr, whereas pH, alkalinity, Ca, and Sr increase. Oxygen isotopes indicate a higher water/rock ratio in the three systems on Valu Fa Ridge, consistent with higher porosity in more felsic volcanic rocks. Vent waters at the Mariner vent field on the Valu Fa Ridge are significantly hotter, more acid and metal-rich, less saline, and richer in dissolved gases and other volatiles, including H2S, CO2, and F, than the other vent fields, consistent with input of magmatic gases. The large variations in geologic and geophysical parameters produced by back-arc spreading along the ELSC, which exceed those along mid-ocean ridge spreading axes, produce similar large variations in the composition of vent waters, and thus provide new insights into the processes that control the chemistry of submarine hot springs.},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2010.12.008},
	url = {http://dx.doi.org/10.1016/j.gca.2010.12.008},
	author = {Mottl, M J and Seewald, J S and Wheat, C G and Tivey, M K and Michael, P J and Proskurowski, G and McCollom, T M and Reeves, E and Sharkey, J and You, C F and Chan, L H and Pichler, T}
}
@article {Smith2011,
	title = {{In situ enrichment of ocean crust microbes on igneous minerals and glasses using an osmotic flow-through device}},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {12},
	year = {2011},
	pages = {Q06007},
	abstract = {The Integrated Ocean Drilling Program (IODP) Hole 1301A on the eastern flank of Juan de Fuca Ridge was used in the first long-term deployment of microbial enrichment flow cells using osmotically driven pumps in a subseafloor borehole. Three novel osmotically driven colonization systems with unidirectional flow were deployed in the borehole and incubated for 4 years to determine the microbial colonization preferences for 12 minerals and glasses present in igneous rocks. Following recovery of the colonization systems, we measured cell density on the minerals and glasses by fluorescent staining and direct counting and found some significant differences between mineral samples. We also determined the abundance of mesophilic and thermophilic culturable organotrophs grown on marine R2A medium and identified isolates by partial 16S or 18S rDNA sequencing. We found that nine distinct phylotypes of culturable mesophilic oligotrophs were present on the minerals and glasses and that eight of the nine can reduce nitrate and oxidize iron. Fe(II)-rich olivine minerals had the highest density of total countable cells and culturable organotrophic mesophiles, as well as the only culturable organotrophic thermophiles. These results suggest that olivine (a common igneous mineral) in seawater-recharged ocean crust is capable of supporting microbial communities, that iron oxidation and nitrate reduction may be important physiological characteristics of ocean crust microbes, and that heterogeneously distributed minerals in marine igneous rocks likely influence the distribution of microbial communities in the ocean crust.},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {1525-2027},
	doi = {10.1029/2010GC003424},
	url = {http://dx.doi.org/10.1029/2010GC003424},
	author = {Smith, A and Popa, R and Fisk, M and Nielsen, M and Wheat, C G and Jannasch, H W and Fisher, A T and Becker, K and Sievert, S M and Flores, G}
}
@article {Fueri2010,
	title = {{Carbon release from submarine seeps at the Costa Rica fore arc: Implications for the volatile cycle at the Central America convergent margin}},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {11},
	year = {2010},
	pages = {Q04S21},
	abstract = {We report total dissolved inorganic carbon (DIC) abundances and isotope ratios, as well as helium isotope ratios (3He/4He), of cold seep fluids sampled at the Costa Rica fore arc in order to evaluate the extent of carbon loss from the submarine segment of the Central America convergent margin. Seep fluids were collected over a 12 month period at Mound 11, Mound 12, and Jaco Scar using copper tubing attached to submarine flux meters operating in continuous pumping mode. The fluids show minimum 3He/4He ratios of 1.3 RA (where RA is air 3He/4He), consistent with a small but discernable contribution of mantle-derived helium. At Mound 11, $δ$13C∑CO2 values between -23.9{\textperthousand} and -11.6{\textperthousand} indicate that DIC is predominantly derived from deep methanogenesis and is carried to the surface by fluids derived from sediments of the subducting slab. In contrast, at Mound 12, most of the ascending dissolved methane is oxidized due to lower flow rates, giving extremely low $δ$13C∑CO2 values ranging from -68.2{\textperthousand} to -60.3{\textperthousand}. We estimate that the carbon flux (CO2 plus methane) through submarine fluid venting at the outer fore arc is 8.0 {\texttimes} 105 g C km-1 yr-1, which is virtually negligible compared to the total sedimentary carbon input to the margin and the output at the volcanic front. Unless there is a significant but hitherto unidentified carbon flux at the inner fore arc, the implication is that most of the carbon being subducted in Costa Rica must be transferred to the (deeper) mantle, i.e., beyond the depth of arc magma generation.},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {1525-2027},
	doi = {10.1029/2009GC002810},
	url = {http://dx.doi.org/10.1029/2009GC002810},
	author = {Fueri, E and Hilton, D R and Tryon, M D and Brown, K M and McMurtry, G M and Brueckmann, W and Wheat, C G}
}
@article {Hulme2010,
	title = {{Pore water chemistry of the Mariana serpentinite mud volcanoes: A window to the seismogenic zone}},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {11},
	year = {2010},
	pages = {Q01X09},
	abstract = {In 2003, we conducted a survey of 11 serpentinite mud volcanoes in the Mariana fore arc. Here we report sediment pore water data from navigated gravity and piston cores and from push cores collected by the ROV system Jason2-Medea. Systematic variations in profiles of pore water chemical compositions from these mud volcanoes are consistent with models that include active upflow of pore water relative to the surrounding serpentinite matrix. The speed of upwelling, based on fits of an advection-diffusion model to observed data (K, Na, Rb, and Cs), reaches a maximum of 36 cm/yr at Big Blue Seamount. Results from these simulations constrain the pore water composition at depth and the degree of additional alteration as the pore water ascends through the sampled section. For example, the transition metals (e.g., Mn, Fe, Co, Ni, Cu, and Mo) are mobilized under conditions of low upwelling speeds and microbial activity. Similarly, the rare earth elements (REE) show evidence of near-surface alteration. In addition to these surficial reactions, distinctive pore water compositional patterns exist as a function of the distance from the trench axis, which is a proxy for the depths of water generation from the downgoing plate below each seamount. Systematic trends in the chemical composition of these slab-sourced fluids are consistent with increasing temperature and pressure at depth west of the trench. These trends include an increase in K, sulfate, carbonate alkalinity, Na/Cl, B, Mn, Fe, Co, Rb, Cs, Gd/Tb, Eu, and light REE (LREE) and a decrease in Ca, Sr, and Y with increasing distance from the trench. Mg and U are universally depleted in the upwelling water. We constrain the thermal conditions along the d{\'e}collement using concentrations of fluid mobile elements (K, B, Cs, and Rb) and the mobilization of LREE relative to heavy REE (HREE). The 80{\textdegree}C isotherm is estimated at a depth of 15 km between Blue Moon Seamount and Cerulean Springs. At slab depths of 17 to 24 km, pore waters lack significant Rb and K enrichments relative to seawater, suggesting an upper bound near 150{\textdegree}C. There is an observed enrichment in LREE relative to HREE at Big Blue Seamount (slab depth 25 km) indicating that the d{\'e}collement at this site is \~{}200{\textdegree}C. The relative mobilization of Cs outpaced that of Rb at all seamounts sampled in this survey. On the basis of laboratory experiments, this observation sets an upper limit of \~{}350{\textdegree}C at a depth of 30 km below the seafloor.},
	keywords = {ROV Jason (Remotely Operated Vehicle), ROV Medea (Remotely Operated Vehicle)},
	issn = {1525-2027},
	doi = {10.1029/2009GC002674},
	url = {http://dx.doi.org/10.1029/2009GC002674},
	author = {Hulme, S M and Wheat, C G and Fryer, P and Mottl, M J}
}
@article {Solomon2009,
	title = {{Long-term hydrogeochemical records in the oceanic basement and forearc prism at the Costa Rica subduction zone}},
	journal = {Earth and Planetary Science Letters},
	volume = {282},
	number = {1-4},
	year = {2009},
	pages = {240{\textendash}251},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2009.03.022},
	url = {http://dx.doi.org/10.1016/j.epsl.2009.03.022},
	author = {Solomon, E A and Kastner, M and Wheat, C G and Jannasch, H W and Robertson, G and Davis, E E and Morris, J D}
}
@article {Wheat2008,
	title = {{Borehole observations of fluid flow from South Chamorro Seamount, an active serpentinite mud volcano in the Mariana forearc}},
	journal = {Earth and Planetary Science Letters},
	volume = {267},
	number = {3-4},
	year = {2008},
	pages = {401{\textendash}409},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	issn = {0012-821X},
	doi = {10.1016/j.epsl.2007.11.057},
	url = {http://dx.doi.org/10.1016/j.epsl.2007.11.057},
	author = {Wheat, C G and Fryer, P and Fisher, A T and Hulme, S and Jannasch, H W and Mottl, M J}
}
@article {Wheat2005,
	title = {{The potential role of ridge-flank hydrothermal systems on oceanic germanium and silicon balances}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {69},
	number = {8},
	year = {2005},
	pages = {2021{\textendash}2029},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2004.05.046},
	url = {http://dx.doi.org/10.1016/j.gca.2004.05.046},
	author = {Wheat, C G and McManus, J}
}
@article {Mottl2004,
	title = {{Chemistry of springs across the Mariana forearc shows progressive devolatilization of the subducting plate}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {68},
	number = {23},
	year = {2004},
	pages = {4915{\textendash}4933},
	keywords = {ROV Jason (Remotely Operated Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2004.05.037},
	url = {http://dx.doi.org/10.1016/j.gca.2004.05.037},
	author = {Mottl, M A and Wheat, C G and Fryer, P and Gharib, J and Martin, J B}
}
@article {Wheat2004a,
	title = {{Heat flow through a basaltic outcrop on a sedimented young ridge flank}},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {5},
	year = {2004},
	pages = {Article no. Q12006},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {1525-2027},
	doi = {10.1029/2004GC000700},
	url = {http://dx.doi.org/10.1029/2004GC000700},
	author = {Wheat, C G and Mottl, M J and Fisher, A T and Kadko, D and Davis, E E and Baker, E T and Mullineaux, L S and Peterson, C H and Micheli, F and Mills, S W}
}
@article {Wheat2004,
	title = {{Venting formation fluids from deep sea boreholes in a ridge flank setting: ODP Sites 1025 and 1026}},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {5},
	number = {8},
	year = {2004},
	pages = {Article no. Q08007},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {1525-2027},
	doi = {10.1029/2004GC000710},
	url = {http://dx.doi.org/10.1029/2004GC000710},
	author = {Wheat, C G and Jannasch, H W and Kastner, M and Plant, J N and DeCarlo, E H and Lebon, G}
}
@article {Wheat2003,
	title = {{Seawater transport and reaction in upper oceanic basaltic basement: Chemical data from continuous monitoring of sealed boreholes in a ridge flank environment}},
	journal = {Earth and Planetary Science Letters},
	volume = {216},
	number = {4},
	year = {2003},
	pages = {549{\textendash}564},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0012-821X},
	doi = {10.1016/S0012-821X(03)00549-1},
	url = {http://dx.doi.org/10.1016/S0012-821X(03)00549-1},
	author = {Wheat, C G and Jannasch, H W and Kastner, M and Plant, J N and DeCarlo, E H}
}
@article {McManus2002,
	title = {{Oceanic molybdenum isotope fractionation: Diagenesis and hydrothermal ridge-flank alteration}},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {3},
	number = {12},
	year = {2002},
	pages = {Article no. 1078},
	issn = {1525-2027},
	doi = {10.1029/2002GC000356},
	url = {http://dx.doi.org/10.1029/2002GC000356},
	author = {McManus, J and N{\"a}gler, T F and Siebert, C and Wheat, C G and Hammond, D}
}
@article {Wheat2002,
	title = {{Trace element and REE composition of a low-temperature ridge flank hydrothermal spring}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {66},
	number = {21},
	year = {2002},
	pages = {3693{\textendash}3705},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/S0016-7037(02)00894-3},
	url = {http://dx.doi.org/10.1016/S0016-7037(02)00894-3},
	author = {Wheat, C G and Mottl, M J and Rudniki, M}
}
@article {Butterfield2001,
	title = {{Evidence for basaltic Sr in midocean ridge-flank hydrothermal systems and implications for the global oceanic Sr isotope balance}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {65},
	number = {22},
	year = {2001},
	pages = {4141{\textendash}4153},
	keywords = {HOV Alvin (Human Occupied Vehicle), ROV Jason (Remotely Operated Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/S0016-7037(01)00712-8},
	url = {http://dx.doi.org/10.1016/S0016-7037(01)00712-8},
	author = {Butterfield, D A and Nelson, B K and Wheat, C G and Mottl, M J and Roe, K K}
}
@article {Wheat2000,
	title = {{Composition of pore and spring waters from Baby Bare: Global implications of geochemical fluxes from a ridge flank hydrothermal system}},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {64},
	number = {4},
	year = {2000},
	pages = {629{\textendash}642},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0016-7037},
	doi = {10.1016/S0016-7037(99)00347-6},
	url = {http://dx.doi.org/10.1016/S0016-7037(99)00347-6},
	author = {Wheat, C G and Mottl, M J}
}
@article {Becker2000a,
	title = {{A geological and geophysical investigation of Baby Bare, locus of a ridge-flank hydrothermal system in the Cascadia Basin}},
	journal = {Journal of Geophysical Research},
	volume = {105},
	number = {B10},
	year = {2000},
	pages = {23,523{\textendash}557,568},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0148-0227},
	doi = {10.1029/2000JB900204},
	url = {http://dx.doi.org/10.1029/2000JB900204},
	author = {Becker, N C and Wheat, C G and Mottl, M J and Karsten, J L and Davis, E E}
}
@article {Wheat1998,
	title = {{Hydrothermal fluid circulation through the sediment of Crater Lake, Oregon: pore water and heat flow constraints}},
	journal = {Journal of Geophysical Research},
	volume = {103},
	number = {B5},
	year = {1998},
	pages = {9931{\textendash}9944},
	issn = {0148-0227},
	doi = {10.1029/97JB03391},
	url = {http://dx.doi.org/10.1029/97JB03391},
	author = {Wheat, C G and McManus, J and Dymond, J and Collier, R and Whiticar, M}
}
@article {Wheat1995,
	title = {{Mapping the fluid flow of the Mariana Mounds ridge flank hydrothermal system: pore water chemical tracers}},
	journal = {Journal of Geophysical Research},
	volume = {100},
	number = {B5},
	year = {1995},
	pages = {8115{\textendash}8131},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0148-0227},
	doi = {10.1029/95JB00047},
	url = {http://dx.doi.org/10.1029/95JB00047},
	author = {Wheat, C G and McDuff, R E}
}
@inbook {Butterfield1994,
	title = {{Geochemistry of hydrothermal vent fluids from Middle Valley, Juan de Fuca Ridge}},
	booktitle = {Proceedings of the Ocean Drilling Program, Scientific Results},
	volume = {139},
	year = {1994},
	pages = {395{\textendash}410},
	publisher = {Ocean Drilling Program, Texas A{\&}M University},
	organization = {Ocean Drilling Program, Texas A{\&}M University},
	address = {College Station, Tex.},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	doi = {10.2973/odp.proc.sr.139.266.1994},
	url = {http://dx.doi.org/10.2973/odp.proc.sr.139.266.1994},
	author = {Butterfield, D A and McDuff, R E and Franklin, J and Wheat, C G},
	editor = {McQuistion, M K}
}
@article {Lupton1993,
	title = {{Chemical and physical diversity of hydrothermal plumes along the East Pacific Rise, 8 degrees 45{\textquoteright} N to 11 degrees 50{\textquoteright} N}},
	journal = {Geophysical Research Letters},
	volume = {20},
	number = {24},
	year = {1993},
	pages = {2913{\textendash}2916},
	keywords = {HOV Alvin (Human Occupied Vehicle)},
	issn = {0094-8276},
	doi = {10.1029/93GL00906},
	url = {http://dx.doi.org/10.1029/93GL00906},
	author = {Lupton, J E and Baker, E T and Mottl, M J and Sansone, F J and Wheat, C G and Resing, J A and Massoth, G J and Measures, C I and Feely, R A}
}
@mastersthesis {Wheat1990,
	title = {{Fluid circulation and diagenesis in an off-axis hydrothermal system: the Mariana Mounds}},
	volume = {Ph.D.},
	year = {1990},
	pages = {216},
	school = {University of Washington},
	type = {phd},
	address = {Seattle, Wash.},
	author = {Wheat, C G}
}
