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  • 2005-2009  (2)
  • 2000-2004  (8)
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  • 1
    In: Paleoceanography, Hoboken, NJ : Wiley, 1986, 24(2009), 1944-9186
    In: volume:24
    In: year:2009
    In: extent:14
    Description / Table of Contents: The intratest variation in the chemical composition of Globorotalia scitula and G. inflata recovered from a sediment trap sample collected at 3000 m in the North Atlantic in early spring has been investigated using laser ablation inductively coupled plasmamass spectrometry and electron microprobe. Mg/Ca, Li/Ca, B/Ca, Mn/Ca, and Ba/Ca vary by up to a factor of 10 through the test walls. Water column properties, including temperature and salinity, are well documented at the trap site, and the observed variations are too large to be explained by vertical migration of the foraminifera. However, changes in calcite precipitation rate, crystal structure, or the chemical composition of the internal calcification reservoir also cannot, by themselves, fully account for the pattern of intratest variability. Nevertheless, the average Mg/Ca for each chamber generally produces a Mg/Ca temperature that matches that measured in the water column. The exception is small, morphologically distinct G. inflata tests that have anomalously high Mg/Ca.
    Type of Medium: Online Resource
    Pages: 14 , Ill., graph. Darst
    ISSN: 1944-9186
    Language: English
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  • 2
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    PANGAEA
    In:  Supplement to: Decitre, Sylvie; Buatier, Martine D; James, Rachael H (2004): Li and Li isotopic composition of hydrothermally altered sediments at Middle Valley, Juan De Fuca. Chemical Geology, 211(3-4), 363-373, https://doi.org/10.1016/j.chemgeo.2004.07.005
    Publication Date: 2024-01-09
    Description: Li and Li isotopes have been measured in the clay fraction of sediments recovered from the Middle Valley hydrothermal site on the Juan De Fuca Ridge. The Li content of pure detrital clays is 51 ppm while hydrothermal clays and carbonates have lower Li (22+/-11 ppm). However, there is no clear relationship between the mineralogy of the hydrothermal alteration products and their Li content. The d7Li value of the detrital clays is +5.8‰. Hydrothermal clays and carbonates have d7Li in the range of -3.9‰ to +7.8‰; these values do not seem to be dependent on the temperature at which they formed. Modelling of the Li and Li isotope systematics indicates that the fluid from which the alteration products form is significantly enriched in Li (higher than 10000 µmol/kg) relative to pore fluids recovered from within the sediments (up to 589 µmol/kg; [Wheat, C.G., M.J. Mottl, 1994. Data report: trace metal composition of pore water from Sites 855 through 858, Middle valley, Juan De Fuca Ridge. In Mottl, M.J., Davis, E.E., Fisher, A.T., Slack, J.F. (Eds.), Proc. ODP, Sci. Res. 139: 749–755; doi:10.2973/odp.proc.sr.139.269.1994]), and that this Li is derived from sediment. Thus, the alteration products are not in equilibrium with their conjugate pore fluids; rather, the alteration minerals formed at lower water/sediment ratios. This suggests that fluid flow pathways at Middle Valley were more diffuse in the past than they are today.
    Keywords: 139-858A; 139-858B; DRILL; Drilling/drill rig; Joides Resolution; Leg139; North Pacific Ocean; Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 4 datasets
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  • 3
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    PANGAEA
    In:  Supplement to: James, Rachael H; Palmer, Martin R (2000): Marine geochemical cycles of the alkali elements and boron: The role of sediments. Geochimica et Cosmochimica Acta, 64(18), 3111-3122, https://doi.org/10.1016/S0016-7037(00)00418-X
    Publication Date: 2024-01-09
    Description: We have analysed the concentrations of Li, K, Rb, Cs, and B, and the isotopic ratios of Li and B of a suite of pore fluids recovered from ODP Sites 1037 (Leg 169; Escanaba Trough) and 1034 (Leg 169S; Saanich Inlet). In addition, we have analysed dissolved K, Rb, and Cs concentrations for estuarine mixing of the Ganges-Brahmaputra river system. Together, these data sets have been used to assess the role of sediments in the marine geochemical cycles of the alkali elements and boron. Uptake onto clay minerals during estuarine mixing removes 20-30% of the riverine input of dissolved Cs and Rb to the oceans. Prior to this study, the only other recognised sink of Rb and Cs was uptake during low-temperature alteration of the oceanic crust. Even with this additional sink there is an excess of inputs over outputs in their modern oceanic mass balance. Pore fluid data show that Li and Rb are transferred into marine sediments during early diagenesis. However, modeling of the Li isotope systematics of the pore fluids from Site 1037 shows that seawater Li taken up during marine sedimentation can be readily returned to solution in the presence of less hydrated cations, such as NH4+. This process also appears to result in high concentrations of pore fluid Cs (relative to local seawater) due to expulsion of adsorbed Cs from cation exchange sites. Flux calculations based on pore fluid data for a series of ODP sites indicate that early diagenesis of clay sediments removes around 8% of the modern riverine input of dissolved Li. Although NH4+-rich fluids do result in a flux of Cs to the oceans, on the global scale this input only augments the modern riverine Cs flux by ~3%. Nevertheless, this may have implications for the fate of radioactive Cs in the natural environment and waste repositories.
    Keywords: 169-1034; 169-1037; Coastal waters of SE Alaska; COMPCORE; Composite Core; Escanaba Trough, North Pacific Ocean; Joides Resolution; Leg169; Leg169S; Ocean Drilling Program; ODP
    Type: Dataset
    Format: application/zip, 2 datasets
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  • 4
    Publication Date: 2024-01-09
    Keywords: 139-858B; Atomic absorption spectrometry (AAS); Calculated; Coefficient; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Joides Resolution; Leg139; Lithium; Mass spectrometer Finnigan MAT 261; North Pacific Ocean; Ocean Drilling Program; ODP; Sample code/label; Sample comment; δ6Li
    Type: Dataset
    Format: text/tab-separated-values, 40 data points
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  • 5
    Publication Date: 2024-01-09
    Keywords: 139-858A; Calcite; Chlorite; Clay minerals; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Feldspar; Illite; Joides Resolution; Leg139; Mica; North Pacific Ocean; Ocean Drilling Program; ODP; Quartz; Sample code/label; Sample comment; Smectite; Sulfate; Temperature, calculated; δ13C; δ18O; δ Deuterium
    Type: Dataset
    Format: text/tab-separated-values, 79 data points
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  • 6
    Publication Date: 2024-01-09
    Keywords: 139-858B; Calcite; Chlorite; Clay minerals; Corrensite; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Feldspar; Illite; Joides Resolution; Leg139; Mica; North Pacific Ocean; Ocean Drilling Program; ODP; Pyrite, FeS2; Quartz; Sample code/label; Sample comment; Smectite; Sulfate; Talc; Temperature, calculated; δ18O; δ Deuterium
    Type: Dataset
    Format: text/tab-separated-values, 80 data points
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  • 7
    Publication Date: 2024-01-09
    Keywords: 169-1037; Ammonium; Atomic absorption spectrometry (AAS); Boron; Caesium; Colorometric analysis, manual; COMPCORE; Composite Core; DEPTH, sediment/rock; DSDP/ODP/IODP sample designation; Escanaba Trough, North Pacific Ocean; Joides Resolution; Leg169; Lithium; Measured in situ; Ocean Drilling Program; ODP; Potassium; Rubidium; Sample code/label; Sample comment; Thermal Ionization Mass Spectrometry (TIMS); δ11B; δ6Li
    Type: Dataset
    Format: text/tab-separated-values, 379 data points
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  • 8
    Publication Date: 2024-01-09
    Keywords: 139-858A; Atomic absorption spectrometry (AAS); Calculated; Coefficient; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Joides Resolution; Leg139; Lithium; Mass spectrometer Finnigan MAT 261; North Pacific Ocean; Ocean Drilling Program; ODP; Sample code/label; Sample comment; δ6Li
    Type: Dataset
    Format: text/tab-separated-values, 39 data points
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  • 9
    Publication Date: 2024-03-02
    Keywords: 169-1034; Ammonium; Atomic absorption spectrometry (AAS); Boron; Caesium; Coastal waters of SE Alaska; Colorometric analysis, manual; COMPCORE; Composite Core; DEPTH, sediment/rock; DSDP/ODP/IODP sample designation; Joides Resolution; Leg169S; Lithium; Measured in situ; Ocean Drilling Program; ODP; Potassium; Rubidium; Sample code/label; Thermal Ionization Mass Spectrometry (TIMS); δ6Li
    Type: Dataset
    Format: text/tab-separated-values, 159 data points
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  • 10
    Publication Date: 2017-10-13
    Description: More than 250 plumes of gas bubbles have been discovered emanating from the seabed of the West Spitsbergen continental margin, in a depth range of 150– 400 m, at and above the present upper limit of the gas hydrate stability zone (GHSZ). Some of the plumes extend upward to within 50 m of the sea surface. The gas is predominantly methane. Warming of the northward-flowing West Spitsbergen current by 1° C over the last thirty years is likely to have increased the release of methane from the seabed by reducing the extent of the GHSZ, causing the liberation of methane from decomposing hydrate. If this process becomes widespread along Arctic contine ntal margins, tens of Teragrams of methane per year could be released into the ocean.
    Type: Article , PeerReviewed
    Format: text
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