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    Discovery of a meteoritic ejecta layer containing unmelted impactor fragments at the base of Paleocene lavas, Isle of Skye, Scotland

    Drake, Simon M. and Beard, Andrew and Jones, Adrian P. and Brown, David J. and Fortes, A. Dominic and Millar, I.L. and Carter, Andrew and Baca, J. and Downes, Hilary (2017) Discovery of a meteoritic ejecta layer containing unmelted impactor fragments at the base of Paleocene lavas, Isle of Skye, Scotland. Geology 46 (2), pp. 171-174. ISSN 0091-7613.

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    Abstract

    Evidence for meteorite impacts in the geological record may include the presence of shocked minerals, spherule layers, and geochemical anomalies. However, it is highly unusual to nd unmelted crystals from the actual impactor within an ejecta layer. Here we detail the rst recorded occurrence of vanadium-rich osbornite (TiVN) on Earth, from two sites on Skye, northwest Scotland, which are interpreted as part of a meteoritic ejecta layer. TiVN has only previously been reported as dust from comet Wild 2, but on Skye it has been identi ed as an unmelted phase. Both ejecta layer sites also contain niobium-rich osbornite (TiNbN), which has not previously been reported. An extraterrestrial origin for these deposits is strongly supported by the presence of reidite (a high-pressure zircon polymorph), which is only found naturally at sites of meteorite impact. Barringerite [(Fe,Ni)2P], baddeleyite (ZrO2), alabandite (MnS), and carbon-bearing native iron spherules, together with planar deformation features and diaplectic glass in quartz, further support this thesis. We demonstrate through eld relationships and Ar-Ar dating that the meteorite strike occurred during the mid-Paleocene. This is the rst recorded mid-Paleocene impact event in the region and is coincident with the onset of magmatism in the British Palaeogene Igneous Province (BPIP). The Skye ejecta layer deposits provoke important questions regarding their lateral extent at the base of the BPIP and the possibility of their presence elsewhere beneath the much larger North Atlantic Igneous Province.

    Metadata

    Item Type: Article
    Keyword(s) / Subject(s): Meteorite ejecta layer, Isle of Skye, osbornite, barringerite, reidite
    School: Birkbeck Schools and Departments > School of Science > Earth and Planetary Sciences
    Research Centre: Earth and Planetary Sciences, Institute of
    Depositing User: Andrew Beard
    Date Deposited: 14 Dec 2017 10:50
    Last Modified: 29 Jul 2019 10:56
    URI: http://eprints.bbk.ac.uk/id/eprint/20625

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