Geophysical surveys of the sediments of Loch Ness, Scotland: implications for the deglaciation of the Moray Firth Ice Stream, British–Irish Ice Sheet
Article first published online: 21 SEP 2011
Copyright © 2011 John Wiley & Sons, Ltd.
Journal of Quaternary Science
Volume 27, Issue 2, pages 221–232, February 2012
How to Cite
Turner, A. J., Woodward, J., Dunning, S. A., Shine, A. J., Stokes, C. R. and Cofaigh, C. Ó. (2012), Geophysical surveys of the sediments of Loch Ness, Scotland: implications for the deglaciation of the Moray Firth Ice Stream, British–Irish Ice Sheet. J. Quaternary Sci., 27: 221–232. doi: 10.1002/jqs.1538
- Issue published online: 9 FEB 2012
- Article first published online: 21 SEP 2011
- Manuscript Accepted: 24 JUL 2011
- Manuscript Revised: 5 JUL 2011
- Manuscript Received: 10 MAR 2011
- Loch Ness;
- geophysical surveys;
We present results from three geophysical campaigns using high-resolution sub-bottom profiling to image sediments deposited in Loch Ness, Scotland. Sonar profiles show distinct packages of sediment, providing insight into the loch's deglacial history. A recessional moraine complex in the north of the loch indicates initial punctuated retreat. Subsequent retreat was rapid before stabilisation at Foyers Rise formed a large stillstand moraine. Here, the calving margin produced significant volumes of laminated sediments in a proglacial fjord-like environment. Subsequent to this, ice retreated rapidly to the southern end of the loch, where it again deposited a sequence of proglacial laminated sediments. Sediment sequences were then disturbed by the deposition of a thick gravel layer and a large turbidite deposit as a result of a jökulhlaup from the Spean/Roy ice-dammed lake. These sediments are overlain by a Holocene sheet drape. Data indicate: (i) a former tributary of the Moray Firth Ice Stream migrated back into Loch Ness as a major outlet glacier with a calving margin in a fjord-like setting; (ii) there was significant sediment supply to the terminus of this outlet glacier in Loch Ness; and (iii) that jökulhlaups are important for sediment supply into proglacial fjord/lake environments and may compose >20% of proglacial sedimentary sequences. Copyright © 2011 John Wiley & Sons, Ltd.