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  • 2005-2009  (14)
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  • 1
    Electronic Resource
    Electronic Resource
    Archaeal diversity in ODP legacy borehole 892b and associated seawater and sediments of the Cascadia Margin (2005)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology ecology 54 (2005), S. 0 
    Details
    ISSN: 1574-6941
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The Cascadia Margin is a region of active accretionary tectonics characterized by high methane flux accompanied by the formation of sedimentary gas hydrates, carbonate nodules, and carbonate pavements. Several sediment cores have been obtained from this region by the Ocean Drilling Project (ODP), and in some cases the boreholes have been sealed off, serving as sites for long-term observatories. We characterized geochemical parameters and diversity of Archaea in one such “legacy” borehole, ODP site 892b, as well as in bottom water immediately above the borehole and in two nearby sediments. The methane concentrations in the samples varied over five orders of magnitude, from 25 to 35 nM in the bottom water to 1.4 mM in one of the sediment samples. Despite these differences, the Archaeal community in all samples was dominated by gene sequences related to the methanogenic Archaea, a finding that correlates with studies of other environments characterized by high methane flux. The archaeal phylotype richness in borehole ODP 892b was limited to two phylotypes; one specifically related to Methanosaeta spp., the other to the anaerobic methane oxidizing ANME-1 group. Although some similar groups were observed in nearby sediment and seawater samples, their archaeal phylotype richness was significantly higher than in the borehole. The possible presence of a dynamic microbial community in the Cascadia Margin sub-surface and its potential roles in methanogenesis, anaerobic oxidation of methane, and authigenic precipitation of carbonate in the Cascadia Margin are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/j.femsec.2005.03.015
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    Paper (German National Licenses)
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  • 2
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    Active methane venting observed at giant pockmarks along the U.S. mid-Atlantic shelf break (2008)
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 267 (2008): 341-352, doi:10.1016/j.epsl.2007.11.053.
    Description: Detailed near-bottom investigation of a series of giant, kilometer scale, elongate pockmarks along the edge of the mid-Atlantic continental shelf confirms that methane is actively venting at the site. Dissolved methane concentrations, which were measured with a commercially available methane sensor (METS) designed by Franatech GmbH mounted on an autonomous underwater vehicle (AUV), are as high as 100 nM. These values are well above expected background levels (1-4 nM) for the open ocean. Sediment pore water geochemistry gives further evidence of methane advection through the seafloor. Isotopically light carbon in the dissolved methane samples indicates a primarily biogenic source. The spatial distribution of the near-bottom methane anomalies (concentrations above open ocean background), combined with water column salinity and temperature vertical profiles, indicate that methane-rich water is not present across the entire width of the pockmarks, but is laterally restricted to their edges. We suggest that venting is primarily along the top of the pockmark walls with some advection and dispersion due to local currents. The highest methane concentrations observed with the METS sensor occur at a small, circular pockmark at the southern end of the study area. This observation is compatible with a scenario where the larger, elongate pockmarks evolve through coalescing smaller pockmarks.
    Description: This work was supported by NSF grants OCE- 0242426, OCE-0242804 and OCDE-0242449 and ONR grant N00014-02-1-0691.
    Keywords: Pockmarks ; Seafloor venting ; Methane ; AUV
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
    Format: application/pdf
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    PAPER (OA)
  • 3
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    Pulsed subduction accretion and tectonic erosion reconstructed since 2.5 Ma from the tephra record offshore Costa Rica (2006)
    American Geophysical Union
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2005. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 6 (2005): Q09016, doi:10.1029/2005GC000963.
    Description: Tephra layers recovered by Ocean Drilling Program from the forearc and trench regions offshore the Nicoya Peninsula of Costa Rica allow the temporal evolution of the volcanic arc to be reconstructed since 2.5 Ma. Major and trace element analyses by microprobe methods reveal a dominant tholeiitic character and a provenance in the Costa Rican area. The tephra show long-term coherent variability in geochemistry. One tephra dated at 1.45 Ma shows minimum values in ɛ Nd and maximum Li/Y consistent with very high degrees of sediment recycling at this time. However, overall Li/Y and δ7Li increase with SiO2 content, suggesting addition of heavy Li through forearc tectonic erosion and crustal assimilation. Peak values in δ7Li starting at 1.45 Ma and lasting ∼0.5 m.y. indicate enhanced tectonic erosion of the forearc possibly caused by subduction of a seamount at 1.45 Ma. The tephra record indicates significant temporal variability in terms of sediment subduction, reconciling the geologic evidence for long-term tectonic erosion and geochemical evidence for recent sediment accretion in the modern Central American arc.
    Description: Financial support for the analytical work was gratefully received from JOI-USSAC. The lithium isotope work was supported in part by National Science Foundation grant OCE-990554 to L.H.C.
    Keywords: Costa Rica ; Subduction ; Geochemistry ; Tephra
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: 1261051 bytes
    Format: application/pdf
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  • 4
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    Shipboard acoustic doppler current profiling during cruise MV9911 (SAC ID 00440) (2005)
    PANGAEA
    Details
    Publication Date: 2023-02-24
    Keywords: Acoustic Doppler Current Profiler; ADCP; Current velocity, east-west; Current velocity, north-south; DATE/TIME; DEPTH, water; LATITUDE; LONGITUDE; Melville; MV9911; MV9911_00440; Shipboard Acoustic Doppler Current Profiling (SADCP); Ship velocity, absolute east-west, standard deviation; Ship velocity, absolute east-west components means; Ship velocity, absolute north-south components mean; Ship velocity, absolute north-south standard deviation; Temperature, technical; Temperature, technical, standard deviation; WOCE; World Ocean Circulation Experiment
    Type: Dataset
    Format: text/tab-separated-values, 11478 data points
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  • 5
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    Barium in sediments and pore waters of several ODP Leg 170 and Leg 205 sites (2006)
    PANGAEA
    In:  Supplement to: Solomon, Evan A; Kastner, Miriam; Robertson, Gretchen (2006): Barium cycling at the Costa Rica convergent margin. In: Morris, JD; Villinger, HW; Klaus, A (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 205, 1-54, https://doi.org/10.2973/odp.proc.sr.205.210.2006
    Details
    Publication Date: 2024-01-09
    Description: Barium concentrations were measured on 17 pore fluid and 13 sediment samples from Sites 1253 and 1254 drilled offshore Costa Rica during Ocean Drilling Program (ODP) Leg 205. An additional 83 pore fluid and 29 sediment samples were analyzed for Ba concentrations from Sites 1039 and 1040 drilled during ODP Leg 170 offshore Costa Rica. Sites 1039/1253 and 1040/1254 are part of a transect across the Middle America Trench offshore Nicoya Peninsula. The entire incoming sediment section is being underthrust beneath the margin, providing an ideal setting to examine Ba cycling in the shallow levels of the subduction zone. Results from these analyses indicate that a significant amount of Ba is liberated from the mineral barite (BaSO4) in the uppermost hemipelagic sediments arcward of the trench. The shallow distillation of Ba may impact the amount of sedimentary Ba reaching the deeper subduction zone.
    Keywords: 170-1039B; 170-1039C; 170-1040C; 205-1253A; 205-1254A; Costa Rica subduction complex, North Pacific Ocean; DRILL; Drilling/drill rig; Joides Resolution; Leg170; Leg205; North Pacific Ocean; Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 2 datasets
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    DATA PANGAEA
  • 6
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    Geochemistry of pore fluids and bulk solids of ODP Site 195-1200, South Chamorro Seamount (2005)
    PANGAEA
    In:  Supplement to: Wei, Wei; Kastner, Miriam; Deyhle, Annette; Spivack, Arthur J (2005): Geochemical cycling of fluorine, chlorine, bromine, and boron and implications for fluid-rock reactions in Mariana forearc, South Chamorro Seamount, ODP Leg 195. In: Shinohara, M; Salisbury, MH; Richter, C (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 195, 1-23, https://doi.org/10.2973/odp.proc.sr.195.106.2005
    Details
    Publication Date: 2024-01-09
    Description: At the South Chamorro Seamount in the Mariana subduction zone, geochemical data of pore fluids recovered from Ocean Drilling Program Leg 195 Site 1200 indicate that these fluids evolved from dehydration of the underthrusting Pacific plate and upwelling of fluids to the surface through serpentinite mud volcanoes as cold springs at their summits. Physical conditions of the fluid source at 27 km were inferred to be at 100°-250°C and 0.8 GPa. The upwelling of fluid is more active near the spring in Holes 1200E and 1200A and becomes less so with increasing distance toward Hole 1200D. These pore fluids are depleted in Cl and Br, enriched in F (except in Hole 1200D) and B (up to 3500 µM), have low 11B (16-21), and have lower than seawater Br/Cl ratios. The mixing ratios between seawater and pore fluids is calculated to be ~2:1 at shallow depth. The F, Cl, and Br concentrations, together with B concentrations and B isotope ratios in the serpentinized igneous rocks and serpentine muds that include ultramafic clasts from Holes 1200A, 1200B, 1200D, 1200E, and 1200F, support the conclusion that the fluids involved in serpentinization originated from great depths; the dehydration of sediments and altered basalt at the top of the subducting Pacific plate released Cl, H2O, and B with enriched 10B. Calculation from B concentrations and upwelling rates indicate that B is efficiently recycled through this nonaccretionary subduction zone, as through others, and may contribute the critical missing B of the oceanic cycle.
    Keywords: 195-1200A; 195-1200B; 195-1200D; 195-1200E; 195-1200F; DRILL; Drilling/drill rig; Joides Resolution; Leg195; North Pacific Ocean; Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 2 datasets
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  • 7
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    Fluorine and chlorine concentrations and Cl isotope ratios of serpentines of ODP Site 195-1200 (2008)
    PANGAEA
    In:  Supplement to: Wei, Chih-Lin; Kastner, Miriam; Spivack, Arthur J (2008): Chlorine stable isotopes and halogen concentrations in convergent margins with implications for the Cl isotopes cycle in the ocean. Earth and Planetary Science Letters, 266(1-2), 90-104, https://doi.org/10.1016/j.epsl.2007.11.009
    Details
    Publication Date: 2024-01-09
    Description: Chlorine stable isotopes (delta37Cl) and halogen concentrations (e.g. Br/Cl) in 168 pore Fluids and 23 serpentines and other solids from three subduction zones, the Nankai Trough, Costa Rica, and Mariana Forearc, provide critical information on fluid sources, flow paths, and reaction conditions. The delta37Cl values of pore fluids at the Nankai and Costa Rica subduction zones, are significantly more negative (minimum -7.8‰, 2 sigma +/- 0.3‰) than seawater value (0‰). At Nankai Trough, the minimum delta37Cl value is situated below the décollement and evolves laterally from -7.8‰ at the most arcward ODP Site 808, to -7.1‰ at Site 1174, not, vert, similar 2 km seaward from Site 808, and to -5.8‰ at the reference Site 1173. At Costa Rica, along the décollement the minimum delta37Cl value evolves from -5.5‰ at the most arcward ODP Site 1040/1254, to -3.2‰ at Site 1043/1255, ~1 km seaward, and to 0‰ at the reference Site 1039/1253. At both subduction zones, the Br/Cl ratios are higher than the seawater value (1.5 * 10**-3) and also show seaward evolutions. These pore fluids originate from greater depth arcward, at 〉= 250 °C, from hydrous mineral formation that preferentially incorporates 37Cl and excludes Br. In contrast, the delta37Cl values in the pore fluids at the Mariana serpentine mud volcanoes are higher than the seawater value (+ 0.3‰ to + 1.8‰); and the Br/Cl ratios are lower. These pore fluid values and the high Cl concentrations with positive delta37Cl values (+ 1.2 to + 6.0‰) in the serpentines, support that the upwelling pore fluid originates from dehydration of the subducting slab that releases water enriched in 37Cl, into the fluid phase. The constancy of the ocean delta37Cl over the past 200 Ma suggests that the isotopically fractionated chlorine in serpentinites and the Cl exchanged in subduction zones are efficiently recycled back into seawater. If the efficiency is 〈 100%, the residual would be transferred to the mantle, with a maximum Cl flux between 2 to 3 * 10**17 moles/Ma that would lead to an isotopic difference between the mantle and seawater over the age of the earth on the order of a few per mil.
    Keywords: 195-1200B; 195-1200E; Chloride; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Event label; Fluorine; Joides Resolution; Leg195; North Pacific Ocean; Ocean Drilling Program; ODP; Sample code/label; Sample comment; Thermal Ionization Mass Spectrometry (TIMS); δ37Cl
    Type: Dataset
    Format: text/tab-separated-values, 25 data points
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  • 8
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    (Table 1) Sr-isotope values of representative sediment samples from ODP sites at the Costa Rica margin (2009)
    PANGAEA
    In:  Supplement to: Solomon, Evan A; Kastner, Miriam; Wheat, C Geoffrey; Jannasch, Hans W; Robertson, Gretchen; Davis, Earl E; Morris, Julie (2009): Long-term hydrogeochemical records in the oceanic basement and forearc prism at the Costa Rica subduction zone. Earth and Planetary Science Letters, 282(1-4), 240-251, https://doi.org/10.1016/j.epsl.2009.03.022
    Details
    Publication Date: 2024-01-09
    Description: Two sealed borehole hydrologic observatories (CORKs) were installed in two active hydrogeochemical systems at the Costa Rica subduction zone to investigate the relationship between tectonics, fluid flow, and fluid composition. The observatories were deployed during Ocean Drilling Program (ODP) Leg 205 at Site 1253, ~ 0.2 km seaward of the trench, in the upper igneous basement, and at Site 1255, ~ 0.5 km landward of the trench, in the décollement. Downhole instrumentation was designed to monitor formation fluid flow rates, composition, pressure, and temperature. The two-year records collected by this interdisciplinary effort constitute the first co-registered hydrological, chemical, and physical dataset from a subduction zone, providing critical information on the average and transient state of the subduction thrust and upper igneous basement. The continuous records at ODP Site 1253 show that the uppermost igneous basement is highly permeable hosting an average fluid flow rate of 0.3 m/yr, and indicate that the fluid sampled in the basement is a mixture between seawater (~ 50%) and a subduction zone fluid originating within the forearc (~ 50%). These results suggest that the uppermost basement serves as an efficient pathway for fluid expelled from the forearc that should be considered in models of subduction zone hydrogeology and deformation. Three transients in fluid flow rates were observed along the décollement at ODP Site 1255, two of which coincided with stepwise increases in formation pressure. These two transients are the result of aseismic slip dislocations that propagated up-dip from the seismogenic zone over the course of ~ 2 weeks terminating before reaching ODP Site 1255 and the trench. The nature and temporal behavior of strain and the associated hydrological response during these slow slip events may be an analog for the response of the seaward part of the subduction prism during or soon after large subduction zone earthquakes.
    Keywords: 170-1040C; 170-1041B; 170-1042B; 205-1253A; 205-1254A; Costa Rica margin, North Pacific Ocean; Costa Rica subduction complex, North Pacific Ocean; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Event label; Joides Resolution; Leg170; Leg205; Lithology/composition/facies; North Pacific Ocean; Ocean Drilling Program; ODP; Sample code/label; Strontium-87/Strontium-86 ratio
    Type: Dataset
    Format: text/tab-separated-values, 24 data points
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  • 9
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    (Table T2) Rubidium and Caesium concentrations of sediments from ODP Leg 170 and Leg 205 sites (2006)
    PANGAEA
    Details
    Publication Date: 2024-01-09
    Keywords: 170-1039B; 170-1039C; 170-1040C; 205-1253A; 205-1254A; Caesium; Costa Rica subduction complex, North Pacific Ocean; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Event label; ICP-MS, Thermo Finnigan, Element 2; Joides Resolution; Leg170; Leg205; North Pacific Ocean; Ocean Drilling Program; ODP; Rubidium; Sample code/label
    Type: Dataset
    Format: text/tab-separated-values, 98 data points
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  • 10
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    (Table T1) Barium in pore fluid of sediments from ODP Leg 170 and Leg 205 sites (2006)
    PANGAEA
    Details
    Publication Date: 2024-01-09
    Keywords: 170-1039B; 170-1039C; 170-1040C; 205-1253A; 205-1254A; Barium; Costa Rica subduction complex, North Pacific Ocean; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Event label; ICP-MS, Thermo Finnigan, Element 2; ICP-OES, Inductively coupled plasma - optical emission spectrometry; Joides Resolution; Leg170; Leg205; North Pacific Ocean; Ocean Drilling Program; ODP; Sample code/label
    Type: Dataset
    Format: text/tab-separated-values, 181 data points
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    DATA PANGAEA
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