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  • 1
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    (Table 2) Age determination from different sediment cores of the Juan de Fuca Ridge (2017)
    PANGAEA
    In:  Supplement to: Costa, K M; McManus, Jerry F; Boulahanis, B; Carbotte, S M; Winckler, Gisela; Huybers, Peter; Langmuir, Charles H (2016): Sedimentation, stratigraphy and physical properties of sediment on the Juan de Fuca Ridge. Marine Geology, 380, 163-173, https://doi.org/10.1016/j.margeo.2016.08.003
    Details
    Publication Date: 2024-03-02
    Description: Sedimentation near mid-ocean ridges may differ from pelagic sedimentation due to the influence of the ridges' rough topography on sediment deposition and transport. This study explores whether the near-ridge environment responds to glacial-interglacial changes in climate and oceanography. New benthic d18O, radiocarbon, multi-sensor track, and physical property (sedimentation rates, density, magnetic susceptibility) data for seven cores on the Juan de Fuca Ridge provide multiple records covering the past 700,000 years of oceanographic history of the Northeast Pacific Ocean. Systematic variations in sediment density and coarse fraction correspond to glacial-interglacial cycles identified in benthic d18O, and these observations may provide a framework for mapping the d18O chronostratigraphy via sediment density to other locations on the Juan de Fuca Ridge and beyond. Sedimentation rates generally range from 0.5 to 3 cm/kyr, with background pelagic sedimentation rates close to 1 cm/kyr. Variability in sedimentation rates close to the ridge likely reflects remobilization of sediment caused by the high relief of the ridge bathymetry. Sedimentation patterns primarily reflect divergence of sedimentation rates with distance from the ridge axis and glacial-interglacial variation in sedimentation that may reflect carbonate preservation cycles as well as preferential remobilization of fine material.
    Keywords: Age, 14C calibrated; Age, dated; Age, dated material; Age, dated standard deviation; AT26-19; AT26-19-05PC; AT26-19-09PC; AT26-19-12PC; AT26-19-38PC; Atlantis (1997); Calendar age; Calendar age, standard deviation; DEPTH, sediment/rock; Event label; Juan de Fuca Ridge, North Pacific Ocean; Latitude of event; Longitude of event; PC; Piston corer; Sample ID; see further details
    Type: Dataset
    Format: text/tab-separated-values, 24 data points
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    DATA PANGAEA
  • 2
    Electronic Resource
    Electronic Resource
    The influence of ridge migration on the magmatic segmentation of mid-ocean ridges (2004)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 429 (2004), S. 743-746 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The Earth's mid-ocean ridges display systematic changes in depth and shape, which subdivide the ridges into discrete spreading segments bounded by transform faults and smaller non-transform offsets of the axis. These morphological changes have been attributed to spatial variations in the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature02652
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    A new view of the mid-ocean ridge from the behaviour of ridge-axis discontinuities (1988)
    [s.l.] : Nature Publishing Group
    Nature 335 (1988), S. 217-225 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] High-resolution images covering large areas of the seafloor reveal numerous discontinuities along the mid-ocean ridge. These discontinuities occur at a range of scales (10–1,000 km) and define a fundamental segmentation of seafloor spreading centres. Some are transient; others persist for ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/335217a0
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  • 4
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    Tectonic and magmatic segmentation of the Global Ocean Ridge System: a synthesis of observations (2015)
    Geological Society (of London)
    Details
    Publication Date: 2015-02-08
    Description: Mid-ocean ridges display tectonic segmentation defined by discontinuities of the axial zone, and geophysical and geochemical observations suggest segmentation of the underlying magmatic plumbing system. Here, observations of tectonic and magmatic segmentation at ridges spreading from fast to ultraslow rates are reviewed in light of influential concepts of ridge segmentation, including the notion of hierarchical segmentation, spreading cells and centralized v. multiple supply of mantle melts. The observations support the concept of quasi-regularly spaced principal magmatic segments, which are 30–50 km long on average at fast- to slow-spreading ridges and fed by melt accumulations in the shallow asthenosphere. Changes in ridge properties approaching or crossing transform faults are often comparable with those observed at smaller offsets, and even very small discontinuities can be major boundaries in ridge properties. Thus, hierarchical segmentation models that suggest large-scale transform fault-bounded segmentation arises from deeper level processes in the asthenosphere than the finer-scale segmentation are not generally supported. The boundaries between some but not all principal magmatic segments defined by ridge axis geophysical properties coincide with geochemical boundaries reflecting changes in source composition or melting processes. Where geochemical boundaries occur, they can coincide with discontinuities of a wide range of scales.
    Print ISSN: 0305-8719
    Electronic ISSN: 2041-4927
    Topics: Geosciences
    Published by Geological Society (of London)
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  • 5
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    A 65 k.y. time series from sediment-hosted glasses reveals rapid transitions in ocean ridge magmas (2017)
    Geological Society of America (GSA)
    In: Geology
    Details
    Publication Date: 2017-05-13
    Description: Studies of ocean ridge magmatism have been hampered by the difficulty in constructing time-series data over more than a few thousand years. Sediment rapidly covers newly formed ocean crust, and older rocks, even when recovered from fault scarps, cannot be dated accurately. Ridge eruptions, however, disperse pyroclastic glass over distances as far as 5 km, and these glasses have been shown to persist for thousands of years in on-ridge sediment push cores. Here we present data on such glasses from a piston core that impacted basement in much older (600 ka) sediment. The age of deposition was determined using established stratigraphic methods to date the host sediment, yielding an average sample resolution of a few thousand years and a continuous 65 k.y. time series. The new time-series data show systematic temporal variations in magma compositions related to a change to the dynamics of crustal storage, which led to greater extents of pre-eruptive differentiation. Shortly thereafter was a small but discernable shift toward more enriched primary melt compositions. These events coincide with the onset of enhanced crustal production, previously identified using seismic data and interpreted to reflect the capture of a hotspot by the ridge. These results show the long-term preservation of pyroclastic glasses and suggest that the construction of high-resolution volcanic stratigraphy over a million years or more may be possible at ocean ridges, using multiple piston cores that impact basement. Sediment-hosted glasses have the potential to transform ocean ridges from the volcanic setting with the worst time-series data to that with the best.
    Print ISSN: 0091-7613
    Electronic ISSN: 1943-2682
    Topics: Geosciences
    Published by Geological Society of America (GSA)
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  • 6
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    Anatomy of an active submarine volcano (2014)
    Geological Society of America (GSA)
    In: Geology
    Details
    Publication Date: 2014-07-31
    Description: Most of the magma erupted at mid-ocean ridges is stored in a mid-crustal melt lens that lies at the boundary between sheeted dikes and gabbros. Nevertheless, images of the magma pathways linking this melt lens to the overlying eruption site have remained elusive. Here, we have used seismic methods to image the thickest magma reservoir observed beneath any spreading center to date, which is principally attributed to the juxtaposition of the Juan de Fuca Ridge with the Cobb hotspot (northwestern USA). Our results reveal a complex melt body, which is ~14 km long, 3 km wide, and up to 1 km thick, beneath the summit caldera. The estimated volume of the reservoir is 18–30 km 3 , more than two orders of magnitude greater than the erupted magma volumes of either the A.D. 1998 or 2011 eruption. Our images show a network of sub-horizontal to shallow-dipping (〈30°) features that we interpret as pathways facilitating melt transport from the magma reservoir to the eruption sites.
    Print ISSN: 0091-7613
    Electronic ISSN: 1943-2682
    Topics: Geosciences
    Published by Geological Society of America (GSA)
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  • 7
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    Distribution of melt along the East Pacific Rise from 9{degrees}30' to 10{degrees}N from an amplitude variation with angle of incidence (AVA) technique (2015)
    Oxford University Press
    Details
    Publication Date: 2015-08-02
    Description: We examine along-axis variations in melt content of the axial magma lens (AML) beneath the fast-spreading East Pacific Rise (EPR) using an amplitude variation with angle of incidence (AVA) crossplotting method applied to multichannel seismic data acquired in 2008. The AVA crossplotting method, which has been developed for and, so far, applied for hydrocarbon prospection in sediments, is for the first time applied to a hardrock environment. We focus our analysis on 2-D data collected along the EPR axis from 9°29.8'N to 9°58.4'N, a region which encompasses the sites of two well-documented submarine volcanic eruptions (1991–1992 and 2005–2006). AVA crossplotting is performed for a ~53 km length of the EPR spanning nine individual AML segments (ranging in length from ~3.2 to 8.5 km) previously identified from the geometry of the AML and disruptions in continuity. Our detailed analyses conducted at 62.5 m interval show that within most of the analysed segments melt content varies at spatial scales much smaller (a few hundred of metres) than the length of the fine-scale AML segments, suggesting high heterogeneity in melt concentration. At the time of our survey, about 2 yr after the eruption, our results indicate that the three AML segments that directly underlie the 2005–2006 lava flow are on average mostly molten. However, detailed analysis at finer-scale intervals for these three segments reveals AML pockets (from 〉62.5 to 812.5 m long) with a low melt fraction. The longest such mushy section is centred beneath the main eruption site at ~9°50.4'N, possibly reflecting a region of primary melt drainage during the 2005–2006 event. The complex geometry of fluid flow pathways within the crust above the AML and the different response times of fluid flow and venting to eruption and magma reservoir replenishment may contribute to the poor spatial correlation between incidence of hydrothermal vents and presence of highly molten AML. The presented results are an important step forward in our ability to resolve small-scale characteristics of the AML and recommend the AVA crossplotting as a tool for examining mid-ocean ridge magma-systems elsewhere.
    Keywords: Marine Geosciences and Applied Geophysics
    Print ISSN: 0956-540X
    Electronic ISSN: 1365-246X
    Topics: Geosciences
    Published by Oxford University Press on behalf of The Deutsche Geophysikalische Gesellschaft (DGG) and the Royal Astronomical Society (RAS).
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  • 8
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    Environmental change and oyster colonization within the Hudson River estuary linked to Holocene climate (2004)
    Springer
    Details
    Publication Date: 2004-05-28
    Print ISSN: 0276-0460
    Electronic ISSN: 1432-1157
    Topics: Geosciences
    Published by Springer
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  • 9
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    Mid-Ocean Ridges: Discontinuities, Segments and Giant Cracks (1991)
    American Association for the Advancement of Science
    Details
    Publication Date: 1991-08-30
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
    Published by American Association for the Advancement of Science
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  • 10
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    The influence of ridge migration on the magmatic segmentation of mid-ocean ridges (2004)
    Springer Nature
    Details
    Publication Date: 2004-06-01
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Published by Springer Nature
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