Aspects of the glacial and postglacial history of North-West Argyll
dc.contributor.advisor
Sissons, J. B.
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dc.contributor.advisor
Newey, W. W.
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dc.contributor.author
Wain-Hobson, Timothy
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dc.contributor.sponsor
Natural Environment Research Council (NERC)
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dc.date.accessioned
2015-10-08T14:06:50Z
dc.date.available
2015-10-08T14:06:50Z
dc.date.issued
1981
dc.description.abstract
The Loch Lomond Advance limits and raised marine shorelines in N. W. Argyll have been mapped and surveyed. Radiocarbon dated Lateglacial and Postglacial pollen sites at Salen and Loch Shiel provide
the vegetational history and chronology for the area. 14 Loch Lomond Advance glacier termini and associated limits were mapped using the distribution of hummocky and fluted moraine, together with a survey of erratic boulders. 83% of the reconstructed former glaciers had a southerly aspect relating to southerly snow-bearing winds. The average firnline gradient was 7.5m/km increasing in altitude towards
the north-east; the average firnline height for the area was 369m. The Main Lateglacial Shoreline, formed during the Loch Lomond Stadial, slopes towards 270 with a gradient of 0.15m/km from 9m in the
east to Om in the west of the area. It was formed by freeze-thaw action operating under exceptional conditions, and its formation was influenced by rock type. Two Postglacial shorelines are recognized :
the Main Postglacial shoreline that slopes towards 270, from 14m to 8m with a gradient of 0.06m/km, and a lower shoreline at approximately 5m which has no definite gradient. An absolute Lateglacial pollen site at Salen, Ardnamurchan, shows an early pioneer community of Rumex, Salix, Gramineae and Cyperaceae species being replaced by an Empetrum heath during the Lateglacial Interstadial. Subsequent stadial conditions are reflected by open herb communities and the onset of coarse minerogenic sedimentation. This minerogenic influx ceased around 10,000 to 9,700 B.P. with a rapid recolonization of the surrounding area by pioneer herbs, then dwarf shrub and finally deciduous woodland. Middle and Late Postglacial vegetational development is recorded by lacustrine sediments from Loch Shiel where the fossil pollen record shows that a mixed deciduous woodland of Quercus, Alnus, Betula and Corylus was progressively cleared by man. Palaeomagnetic and chemical
records were obtained from the site. The Main Postglacial Transgression flooded Loch Shiel resulting in the deposition of shells of the marine bivlave Thyasira flexonosa.
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dc.identifier.uri
http://hdl.handle.net/1842/10616
dc.language.iso
en
dc.publisher
The University of Edinburgh
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dc.relation.haspart
The University of Edinburgh. College of Science and Engineering
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dc.relation.hasversion
BALLANTYNE, C. K. & WAIN-HOBSON, T. 1980. The Loch Lomond Advance on the Isle of Rhum. Scott. J. geol. 1. 1- 10.
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dc.relation.hasversion
THOMPSON, R. & WAIN-HOBSON, T. 1979. Palaeomagnetic and stratigraphic study of the Loch Shiel marine regression and overlying gyttja. J. geol. Sci. Lond. 136. 383 - 388.
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dc.subject
Loch Lomond Advance
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dc.subject
Glaciation
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dc.subject
Postglacial shorelines
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dc.title
Aspects of the glacial and postglacial history of North-West Argyll
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dc.type
Thesis or Dissertation
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dc.type.qualificationlevel
Doctoral
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dc.type.qualificationname
PhD Doctor of Philosophy
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