Iceberg-rafted tephra as a potential tool for the reconstruction of ice-sheet processes and ocean surface circulation in the glacial North Atlantic
Marion Kuhs, William E. N. Austin, Peter M. Abbott, David A. Hodell, 2014. "Iceberg-rafted tephra as a potential tool for the reconstruction of ice-sheet processes and ocean surface circulation in the glacial North Atlantic", Marine Tephrochronology, W. E. N. Austin, P. M. Abbott, S. M. Davies, N. J. G. Pearce, S. Wastegård
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Ice-rafted tephra deposits, of Marine Isotope Stage 6 (MIS 6) age, from Site U 1304 on the Gardar Drift, North Atlantic were examined for their shard size distribution and major element composition. The heterogeneous composition, large shard sizes and association with ice-rafted debris (IRD) indicate that these late MIS 6 deposits were transported by iceberg-rafting from Iceland to Site U 1304. Comparison of individual shard geochemistry with the geochemistry of Holocene volcanic systems from Iceland allows the identification of different potential volcanic source regions. This detailed geochemical analysis, when combined with Icelandic Ice Sheet (IIS) flow models for the Last Glacial Maximum (LGM), suggests that the IIS had calving margins to both the north and south during the late MIS 6 and that icebergs could have been transported to the Site U 1304 by following surface ocean circulation patterns similar to those that prevailed during the LGM. We demonstrate that the descriptive concept of Icelandic glass in the characterization of tephra components within North Atlantic IRD can be significantly improved through quantitative characterization and that such data hold the potential to help constrain surface ocean circulation models, while also potentially yielding new information about the IIS during earlier glacial periods.
Statistical tests, major element concentrations of analysed shards, primary and secondary standards are available at http://www.geolsoc.org.uk/SUP18716
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This Special Publication includes articles presenting recent advances in marine tephrochronological studies and outlines innovative techniques in geochemical fingerprinting, stratigraphy and the understanding of depositional processes.
It represents a significant resource for the palaeoceanographic community at a time when marine tephrochronology is being more widely recognized. It will also serve as a valuable reference to a much wider community of Earth scientists, climate scientists and archaeologists, particularly in highlighting the role of tephra studies in stratigraphy and regional/extra-regional correlations, as well as in tracing the long-term history of regional and global volcanism in the deep-sea archive.