On the origin of a reddened interflow bed within the Palaeocene lava field of North Skye

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doi: 10.1144/sjg32020117
Authors:Bell, B. R.; Williamson, I. T.; Head, F. E.; Jolley, D. W.
Author Affiliations:Primary:
University of Glasgow, Department of Geology and Applied Geology, Glasgow, United Kingdom
Other:
British Geological Survey, United Kingdom
University of Sheffield, United Kingdom
Volume Title:Scottish Journal of Geology
Source:Scottish Journal of Geology, Vol.32(Part 2), p.117-126. Publisher: Scottish Academic Press, Edinburgh, United Kingdom. ISSN: 0036-9276
Publication Date:1996
Note:In English. 30 refs.; illus., incl. strat. col., 2 tables, sketch map
Summary:Synopsis A reddish brown to reddish orange interflow bed from the Palaeocene lava field of north Skye at Lochan nan Dunan is considered to be of epiclastic origin, with features which distinguish it from in situ palaeosols and solely volcaniclastic deposits. It has sharp upper and lower contacts, is clay matrix-supported, and is dominated by clasts of lateritic rock, together with clasts of somewhat altered basaltic rock and siltstone. Also present are: crystals of fresh clinopyroxene (Wo46.26-47.35 En45.29-45.91 Fs6.85-8.18), plagioclase (An70-75) and alkali feldspar (Or30-50Ab50-70An<1); shards of hawaiitic glass; and secondary hydrothermal minerals in a variety of associations. The clasts of lateritic rock and the fine-grained matrix of the bed were both derived from a previously developed palaeosol and the clasts of volcanic and sedimentary material were also derived from considerably weathered material. The crystals and glass shards are considered to have been derived either from primary ash eruptions or from contemporaneous, unaltered ash deposits. Palynological investigations reveal that the bed is devoid of pollen and spores, and contains only fragments of inertinite, indicating that it was exposed at the Earth"s surface for a relatively short time interval, and confirms that the reddening "event" occurred prior to deposition of the bed. The bed contains valuable information about pyroclastic material and phenocryst-bearing magmas not preserved elsewhere in the lava field, and the fresh nature of this material indicates that the time intervals between eruption of the ash, deposition of the bed, and the eruption of the overlying lava flow(s) were relatively short.
Subjects:Cenozoic; Clastic rocks; Inertinite; Lava flows; Macerals; Mineral composition; Paleocene; Paleogene; Red beds; Sedimentary rocks; Tertiary; Volcaniclastics; Volcanism; Europe; Great Britain; Hebrides; Highland region Scotland; Inner Hebrides; Inverness-shire Scotland; Isle of Skye; Scotland; United Kingdom; Western Europe; Lochan nan Dunan Scotland
Coordinates:N570000 N574000 W0054000 W0064500
Abstract Numbers:97M/4391
Record ID:1997029734
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute.
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