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  • 1
    Publication Date: 2024-05-21
    Description: The BRITICE-CHRONO project measured 639 new geochronometric ages that constrain the timing of advance and retreat of the last British-Irish Ice Sheet between 31,000 and 15,000 years ago, including across the North Sea. These ages (optically stimulated luminescence, radiocarbon and terrestrial cosmogenic nuclide methods) are made available in an excel spreadsheet, along with all sample and laboratory metadata and calibrations. Together with other published information, the ages were used to build an empirical ice sheet reconstruction at one thousand year time-steps. A poster-map and slideshow (PDF) of the reconstruction (31 to 15 ka) and the underlying GIS data (ArcGIS shapefiles) of ice extents (min, max and optimum) are made available here. An ice sheet model was nudged to fit these ice limits and the ensuing model-reconstruction is made available as a poster-map, slideshow (PDF) and movie (GIF) of the reconstruction (31 to 15 ka). The GIS data is also available including grounded ice extent and ice shelves, ice thickness, ice surface elevation, and ice velocity (as ArcGIS grids). From glacio-isostatic adjustment modelling we also provide digital elevation models of the palaeotopography of the British Isles and surrounding sea floors and coastline positions from 36 to 1 ka (ArcGIS grids and shapefiles). Full methods, descriptions, caveats and interpretations are available in the parent paper to this dataset: Clark. C.D. et al. (2022) Growth and retreat of the last British-Irish Ice Sheet, 31,000 to 15,000 years ago: the BRITICE-CHRONO reconstruction, Boreas.
    Keywords: Binary Object; Binary Object (File Size); Binary Object (Media Type); BRITICE CHRONO; British Irish Ice Sheet; dating ice retreat; Ice Sheet Modelling
    Type: Dataset
    Format: text/tab-separated-values, 10 data points
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  • 2
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 413 (2001), S. 36-36 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Almost three-quarters of the world's coral reefs are thought to be deteriorating as a consequence of environmental stress. Until now, it has been possible to evaluate reef health only by field survey, which is labour-intensive and time-consuming. Here we map live coral cover from the air by ...
    Type of Medium: Electronic Resource
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  • 3
    Publication Date: 2021-02-08
    Description: The reconstruction of past ice sheet dynamics can inform on long-term ice stream activity, and in turn provide constraints on the response of modern ice sheets to climate change. The Hebrides Ice Stream (HIS) flowed across part of the western Scottish shelf to the shelf-break during the last glacial cycle. To investigate the deglacial dynamics of the HIS following the Last Glacial Maximum (LGM), lead (Pb) isotope records were extracted from the FeMn oxyhydroxide and detrital fractions of recovered laminated glacimarine mud sequences to monitor the changing activity of HIS during its retreat. These provide, respectively, relative timing of glacially weathered inputs to the marine environment and some source information on the eroded sediments. The FeMn oxyhydroxide fraction is dominated by pre-formed particles and shows a marked decrease from radiogenic at ~ 21 cal ka to less radiogenic Pb isotope compositions towards 15.4–13 ka. This decrease represents a reduction in the flux of subglacially-derived radiogenic Pb to the continental shelf, and it is interpreted as the result of the break-up of the ice-stream in western Scotland around that time. The Pb, Sr and Nd isotopic signatures of the detrital fraction indicate a preponderance of fine sediments originated from the NW Highlands throughout the period studied (~ 21 to 15 cal ka BP), most likely dictated by the orientation of tidal and oceanic current directions and sediment delivery. Both fractions show inversion of the 208Pb/204Pb ratio relative to the other Pb isotope ratios. This is observed only in one core site in the detrital fraction, and extended to all cores in the FeMn oxyhydroxide fraction. This behaviour highlights the influence of ocean currents in restricting the detrital but encouraging dispersal of the FeMn oxyhydroxide signal. Periodic increased contributions from a high Th/U source, potentially the neighbouring Archaean amphibolitic Lewisian basement in the Outer Hebrides, are proposed as the source of these 208Pb/204Pb inversions. This study demonstrates how geochemical investigation on continental shelves can be used to constrain the activity and flow sources of palaeo-ice streams, and the utility of combining detrital and FeMn oxyhydroxides to determine the combined influence of the continental sources of material and their dispersal in the marine environment.
    Type: Article , PeerReviewed
    Format: text
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