The Experts below are selected from a list of 1644 Experts worldwide ranked by ideXlab platform
William S D Wilcock - One of the best experts on this subject based on the ideXlab platform.
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seismic evidence that Black Smoker heat flux is influenced by localized magma replenishment and associated increases in crustal permeability
Geophysical Research Letters, 2017Co-Authors: G M Arnoux, William S D Wilcock, Emilie E E Hooft, Douglas R Toomey, Joanna Morgan, M Warner, Brandon P VanderbeekAbstract:Hydrothermal circulation at mid-ocean ridges is responsible for ~25% of Earth's heat flux and controls the thermal and chemical evolution of young oceanic crust. The heat flux of Black Smoker hydrothermal systems is thought to be primarily controlled by localized magma supply and crustal permeability. Nevertheless, magma chamber characteristics and the nature of crustal permeability beneath such systems remains unclear. Here we apply three-dimensional full-waveform inversion to seismic data from the hydrothermally active Endeavour segment of the Juan de Fuca Ridge to image the upper crust in high resolution. We resolve velocity variations directly above the axial magma chamber that correlate with variations in seismicity, Black Smoker heat flux, and the depth of the axial magmatic system. We conclude that localized magma recharge to the axial magma lens, along with induced seismogenic cracking and increased permeability, influences Black Smoker heat flux.
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flow rate perturbations in a Black Smoker hydrothermal vent in response to a mid ocean ridge earthquake swarm
Geochemistry Geophysics Geosystems, 2010Co-Authors: Timothy J Crone, William S D Wilcock, Russell E McduffAbstract:Although there is indirect evidence for strong connections between tectonic processes and mid-ocean ridge hydrothermal flow, there are no direct observations of these links, primarily because measuring flow in these systems is difficult. Here we use an optical analysis technique to obtain a 44 day record of flow rate changes in a Black Smoker vent in the Main Endeavour field of the Juan de Fuca Ridge. We show that variations in the flow rate coincide with an earthquake swarm observed using an ocean bottom seismometer array. These observations indicate that connections between tectonics and flow are indeed strong, that hydraulic connections within this hydrothermal system are long ranging, and that enhanced tidal pumping of fluids may be initiated by earthquake activity. Because the effects of the swarm cross over an intervening vent field, we infer that the upflow zones feeding this field are narrow. Using the time lag between the swarm onset and the flow rate changes we estimate that the bulk permeability of the crust on the Endeavour segment ranges from 3.0 × 10−13 m2 to 6.0 × 10−12 m2.
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the role of magma injection in localizing Black Smoker activity
Nature Geoscience, 2009Co-Authors: William S D Wilcock, Emilie E E Hooft, Douglas R Toomey, P Mcgill, Andrew H Barclay, Debra S Stakes, Tony M RamirezAbstract:The mechanisms for localization of Black-Smoker systems at mid-ocean ridges remain to be fully understood. Seismic data for a segment of the Juan de Fuca ridge with long-lived Black-Smoker vents reveal ongoing magma recharge into the crustal magma chamber, thereby providing an explanation for the localization.
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optical plume velocimetry a new flow measurement technique for use in seafloor hydrothermal systems
Experiments in Fluids, 2008Co-Authors: Timothy J Crone, Russell E Mcduff, William S D WilcockAbstract:Evidence suggests that fluid flow rates in mid-ocean ridge hydrothermal systems may be strongly influenced by mechanical forces such as ocean tidal loading. However, long time-series measurements of flow have not been collected in these environments. We develop a non-invasive method, called optical plume velocimetry (OPV), suitable for obtaining fluid flow rates through Black Smoker vents based on image analysis of effluent video. We use video from laboratory flows to evaluate three different methods for estimating the image-velocity field that are based on region-based matching, spectral-analysis of Hovmoller diagrams, and temporal cross-correlation of adjacent pixel values. We find that OPV is most sensitive and least biased when the cross-correlation method is used and conclude that OPV should not be applied to flows that are transitioning between jet-like and plume-like behavior.
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the sound generated by mid ocean ridge Black Smoker hydrothermal vents
PLOS ONE, 2006Co-Authors: Timothy J Crone, William S D Wilcock, Andrew H Barclay, Jeffrey D ParsonsAbstract:Hydrothermal flow through seafloor Black Smoker vents is typically turbulent and vigorous, with speeds often exceeding 1 m/s. Although theory predicts that these flows will generate sound, the prevailing view has been that Black Smokers are essentially silent. Here we present the first unambiguous field recordings showing that these vents radiate significant acoustic energy. The sounds contain a broadband component and narrowband tones which are indicative of resonance. The amplitude of the broadband component shows tidal modulation which is indicative of discharge rate variations related to the mechanics of tidal loading. Vent sounds will provide researchers with new ways to study flow through sulfide structures, and may provide some local organisms with behavioral or navigational cues.
Xiaotong Peng - One of the best experts on this subject based on the ideXlab platform.
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sr isotopes and rees geochemistry of anhydrites from l vent Black Smoker chimney east pacific rise 9 n 10 n
Journal of Earth Science, 2015Co-Authors: Huiqiang Yao, Xiaotong Peng, Huaiyang ZhouAbstract:High resolution sampling, for Sr isotope and REE analyses, was carried out along a transaction of L vent chimney collected from East Pacific Rise 9°N–10°N. Sr isotopes show these anhydrites are precipitated from a mixture between hydrothermal fluid and seawater. The calculated relative proportion of seawater and hydrothermal fluid shows that the mixing is heterogeneous on the transection of the L vent chimney. Anhydrites from the chimney show uniform chondrite-normalized REE pattern with enrichment of LREE and positive Eu anomaly. While normalized to the REE of end-member hydrothermal fluid, anhydrites also show uniform REE pattern but with negative Eu anomaly and enrichment of HREE. Combining previous studies on REEs of hydrothermal fluids from different hydrothermal systems and the hydrothermal fluid data from this region, we suggested that REE-anion complexing, rather than crystallography controlling, is the main factor that controls the REE partition behavior in the anhydrite during its precipitation from the mixture of hydrothermal fluid and seawater.
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metal sources of Black Smoker chimneys endeavour segment juan de fuca ridge pb isotope constraints
Applied Geochemistry, 2009Co-Authors: Xiaotong Peng, Huaiyang Zhou, Huiqiang Yao, Shenxu Bao, Zhilei SunAbstract:Abstract Hydrothermal chimney sulfides, vent cap chimney samples, Fe-oxide and basalts from sediment-starving Juan de Fuca Ridge, in the Endeavour segment, exhibit a range of Pb isotope ratios ( 206 Pb/ 204 Pb = 18.658–18.769; 207 Pb/ 204 Pb = 15.457–15.566; 208 Pb/ 204 Pb = 37.810–38.276). The data array is not parallel to the northern hemisphere mantle reservoirs indicating a possible sediment component within the sulfides. By assuming that the potential end-member sediment component has a 207 Pb/ 204 Pb (15.70) similar to Middle Valley sediment, it is suggested the potential end-member sediment component may have 206 Pb/ 204 Pb = 18.90; 208 Pb/ 204 Pb = 38.82. Basalt-derived Pb for the Endeavour segment hydrothermal system involves about 50/50 leaching of E-MORB and T2-MORB. Detailed observations show the Mothra field derives more Pb from T2-MORB than the Main Endeavour field does. According to the binary mixing model, the results show little Pb ( NH 4 + , CH 4 and Br/Cl ratios in hydrothermal fluids are consistent with a sediment component within the segment. Reconciling the Pb isotope data with the chemistry data of hydrothermal fluids, it is suggested that the sediment component may be located in a lower temperature recharge zone where Pb could not be mobilized from the sediment.
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Microbial diversity of a sulfide Black Smoker in main endeavour hydrothermal vent field, Juan de Fuca Ridge.
Journal of microbiology (Seoul Korea), 2009Co-Authors: Huaiyang Zhou, Xiaotong Peng, Jun Meng, Fengping WangAbstract:Submarine hydrothermal vents are among the least-understood habitats on Earth but have been the intense focus of research in the past 30 years. An active hydrothermal sulfide chimney collected from the Dudley site in the Main Endeavour vent Field (MEF) of Juan de Fuca Ridge was investigated using mineralogical and molecular approaches. Mineral analysis indicated that the chimney was composed mainly of Fe-, Zn-and Cu-rich sulfides. According to phylogenetic analysis, within the Crenarchaeota, clones of the order Desulfurococcales predominated, comprising nearly 50% of archaeal clones. Euryarchaeota were composed mainly of clones belonging to Thermococcales and deep-sea hydrothermal vent Euryarchaeota (DHVE), each of which accounted for about 20% of all clones. Thermophilic or hyperthermophilic physiologies were common to the predominant archaeal groups. More than half of bacterial clones belonged to ɛ-Proteobacteria, which confirmed their prevalence in hydrothermal vent environments. Clones of Proteobacteria (γ-, δ-, β-), Cytophaga-Flavobacterium-Bacteroides (CFB) and Deinococcus-Thermus occurred as well. It was remarkable that methanogens and methanotrophs were not detected in our 16S rRNA gene library. Our results indicated that sulfur-related metabolism, which included sulfur-reducing activity carried out by thermophilic archaea and sulfur-oxidizing by mesophilic bacteria, was common and crucial to the vent ecosystem in Dudley hydrothermal site.
Rita Fonseca - One of the best experts on this subject based on the ideXlab platform.
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discovery of a Black Smoker vent field and vent fauna at the arctic mid ocean ridge
Nature Communications, 2010Co-Authors: Rolf B Pedersen, Hans Tore Rapp, Ingunn H Thorseth, Marvin D Lilley, Fernando J A S Barriga, Tamara Baumberger, Kristin Flesland, Rita Fonseca, Gretchen L FruhgreenAbstract:The Arctic Mid-Ocean Ridge (AMOR) represents one of the most slow-spreading ridge systems on Earth. Previous attempts to locate hydrothermal vent fields and unravel the nature of venting, as well as the provenance of vent fauna at this northern and insular termination of the global ridge system, have been unsuccessful. Here, we report the first discovery of a Black Smoker vent field at the AMOR. The field is located on the crest of an axial volcanic ridge (AVR) and is associated with an unusually large hydrothermal deposit, which documents that extensive venting and long-lived hydrothermal systems exist at ultraslow-spreading ridges, despite their strongly reduced volcanic activity. The vent field hosts a distinct vent fauna that differs from the fauna to the south along the Mid-Atlantic Ridge. The novel vent fauna seems to have developed by local specialization and by migration of fauna from cold seeps and the Pacific. The Arctic Mid-Ocean Ridge spreads extremely slowly and hydrothermal vent fields have not been reported in its vicinity. Pedersenet al. describe a Black Smoker vent field with large hydrothermal deposits and novel fauna distinct from those found in similar environments in the Atlantic.
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discovery of a Black Smoker vent field and vent fauna at the arctic mid ocean ridge
Nature Communications, 2010Co-Authors: Rolf B Pedersen, Hans Tore Rapp, Ingunn H Thorseth, Fernando J A S Barriga, Tamara Baumberger, Kristin Flesland, Rita Fonseca, Gretchen L Fruhgreen, Steffen L JorgensenAbstract:The Arctic Mid-Ocean Ridge spreads extremely slowly and hydrothermal vent fields have not been reported in its vicinity. Pedersen et al. describe a Black Smoker vent field with large hydrothermal deposits and novel fauna distinct from those found in similar environments in the Atlantic.
Gretchen L Fruhgreen - One of the best experts on this subject based on the ideXlab platform.
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discovery of a Black Smoker vent field and vent fauna at the arctic mid ocean ridge
Nature Communications, 2010Co-Authors: Rolf B Pedersen, Hans Tore Rapp, Ingunn H Thorseth, Marvin D Lilley, Fernando J A S Barriga, Tamara Baumberger, Kristin Flesland, Rita Fonseca, Gretchen L FruhgreenAbstract:The Arctic Mid-Ocean Ridge (AMOR) represents one of the most slow-spreading ridge systems on Earth. Previous attempts to locate hydrothermal vent fields and unravel the nature of venting, as well as the provenance of vent fauna at this northern and insular termination of the global ridge system, have been unsuccessful. Here, we report the first discovery of a Black Smoker vent field at the AMOR. The field is located on the crest of an axial volcanic ridge (AVR) and is associated with an unusually large hydrothermal deposit, which documents that extensive venting and long-lived hydrothermal systems exist at ultraslow-spreading ridges, despite their strongly reduced volcanic activity. The vent field hosts a distinct vent fauna that differs from the fauna to the south along the Mid-Atlantic Ridge. The novel vent fauna seems to have developed by local specialization and by migration of fauna from cold seeps and the Pacific. The Arctic Mid-Ocean Ridge spreads extremely slowly and hydrothermal vent fields have not been reported in its vicinity. Pedersenet al. describe a Black Smoker vent field with large hydrothermal deposits and novel fauna distinct from those found in similar environments in the Atlantic.
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discovery of a Black Smoker vent field and vent fauna at the arctic mid ocean ridge
Nature Communications, 2010Co-Authors: Rolf B Pedersen, Hans Tore Rapp, Ingunn H Thorseth, Fernando J A S Barriga, Tamara Baumberger, Kristin Flesland, Rita Fonseca, Gretchen L Fruhgreen, Steffen L JorgensenAbstract:The Arctic Mid-Ocean Ridge spreads extremely slowly and hydrothermal vent fields have not been reported in its vicinity. Pedersen et al. describe a Black Smoker vent field with large hydrothermal deposits and novel fauna distinct from those found in similar environments in the Atlantic.
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a serpentinite hosted ecosystem the lost city hydrothermal field
Science, 2005Co-Authors: Deborah S Kelley, Gretchen L Fruhgreen, Jeffrey A Karson, Dana R Yoerger, Timothy M Shank, David A Butterfield, J M Hayes, Matthew O Schrenk, Eric J Olson, Giora ProskurowskiAbstract:The serpentinite-hosted Lost City hydrothermal field is a remarkable submarine ecosystem in which geological, chemical, and biological processes are intimately interlinked. Reactions between seawater and upper mantle peridotite produce methane- and hydrogen-rich fluids, with temperatures ranging from <40° to 90°C at pH 9 to 11, and carbonate chimneys 30 to 60 meters tall. A low diversity of microorganisms related to methane-cycling Archaea thrive in the warm porous interiors of the edifices. Macrofaunal communities show a degree of species diversity at least as high as that of Black Smoker vent sites along the Mid-Atlantic Ridge, but they lack the high biomasses of chemosynthetic organisms that are typical of volcanically driven systems.
Huaiyang Zhou - One of the best experts on this subject based on the ideXlab platform.
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sr isotopes and rees geochemistry of anhydrites from l vent Black Smoker chimney east pacific rise 9 n 10 n
Journal of Earth Science, 2015Co-Authors: Huiqiang Yao, Xiaotong Peng, Huaiyang ZhouAbstract:High resolution sampling, for Sr isotope and REE analyses, was carried out along a transaction of L vent chimney collected from East Pacific Rise 9°N–10°N. Sr isotopes show these anhydrites are precipitated from a mixture between hydrothermal fluid and seawater. The calculated relative proportion of seawater and hydrothermal fluid shows that the mixing is heterogeneous on the transection of the L vent chimney. Anhydrites from the chimney show uniform chondrite-normalized REE pattern with enrichment of LREE and positive Eu anomaly. While normalized to the REE of end-member hydrothermal fluid, anhydrites also show uniform REE pattern but with negative Eu anomaly and enrichment of HREE. Combining previous studies on REEs of hydrothermal fluids from different hydrothermal systems and the hydrothermal fluid data from this region, we suggested that REE-anion complexing, rather than crystallography controlling, is the main factor that controls the REE partition behavior in the anhydrite during its precipitation from the mixture of hydrothermal fluid and seawater.
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metal sources of Black Smoker chimneys endeavour segment juan de fuca ridge pb isotope constraints
Applied Geochemistry, 2009Co-Authors: Xiaotong Peng, Huaiyang Zhou, Huiqiang Yao, Shenxu Bao, Zhilei SunAbstract:Abstract Hydrothermal chimney sulfides, vent cap chimney samples, Fe-oxide and basalts from sediment-starving Juan de Fuca Ridge, in the Endeavour segment, exhibit a range of Pb isotope ratios ( 206 Pb/ 204 Pb = 18.658–18.769; 207 Pb/ 204 Pb = 15.457–15.566; 208 Pb/ 204 Pb = 37.810–38.276). The data array is not parallel to the northern hemisphere mantle reservoirs indicating a possible sediment component within the sulfides. By assuming that the potential end-member sediment component has a 207 Pb/ 204 Pb (15.70) similar to Middle Valley sediment, it is suggested the potential end-member sediment component may have 206 Pb/ 204 Pb = 18.90; 208 Pb/ 204 Pb = 38.82. Basalt-derived Pb for the Endeavour segment hydrothermal system involves about 50/50 leaching of E-MORB and T2-MORB. Detailed observations show the Mothra field derives more Pb from T2-MORB than the Main Endeavour field does. According to the binary mixing model, the results show little Pb ( NH 4 + , CH 4 and Br/Cl ratios in hydrothermal fluids are consistent with a sediment component within the segment. Reconciling the Pb isotope data with the chemistry data of hydrothermal fluids, it is suggested that the sediment component may be located in a lower temperature recharge zone where Pb could not be mobilized from the sediment.
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Microbial diversity of a sulfide Black Smoker in main endeavour hydrothermal vent field, Juan de Fuca Ridge.
Journal of microbiology (Seoul Korea), 2009Co-Authors: Huaiyang Zhou, Xiaotong Peng, Jun Meng, Fengping WangAbstract:Submarine hydrothermal vents are among the least-understood habitats on Earth but have been the intense focus of research in the past 30 years. An active hydrothermal sulfide chimney collected from the Dudley site in the Main Endeavour vent Field (MEF) of Juan de Fuca Ridge was investigated using mineralogical and molecular approaches. Mineral analysis indicated that the chimney was composed mainly of Fe-, Zn-and Cu-rich sulfides. According to phylogenetic analysis, within the Crenarchaeota, clones of the order Desulfurococcales predominated, comprising nearly 50% of archaeal clones. Euryarchaeota were composed mainly of clones belonging to Thermococcales and deep-sea hydrothermal vent Euryarchaeota (DHVE), each of which accounted for about 20% of all clones. Thermophilic or hyperthermophilic physiologies were common to the predominant archaeal groups. More than half of bacterial clones belonged to ɛ-Proteobacteria, which confirmed their prevalence in hydrothermal vent environments. Clones of Proteobacteria (γ-, δ-, β-), Cytophaga-Flavobacterium-Bacteroides (CFB) and Deinococcus-Thermus occurred as well. It was remarkable that methanogens and methanotrophs were not detected in our 16S rRNA gene library. Our results indicated that sulfur-related metabolism, which included sulfur-reducing activity carried out by thermophilic archaea and sulfur-oxidizing by mesophilic bacteria, was common and crucial to the vent ecosystem in Dudley hydrothermal site.