A.J. Turner
Geophysical surveys of the sediments of Loch Ness, Scotland: implications for the deglaciation of the Moray Firth Ice Stream, British-Irish Ice Sheet
Turner, A.J.; Woodward, J.; Dunning, S.A.; Shine, A.J.; Stokes, C.R.; O'Cofaigh, C.
Authors
J. Woodward
S.A. Dunning
A.J. Shine
Professor Chris Stokes c.r.stokes@durham.ac.uk
Professor
C. O'Cofaigh
Abstract
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.
Citation
Turner, A., Woodward, J., Dunning, S., Shine, A., Stokes, C., & O'Cofaigh, C. (2012). Geophysical surveys of the sediments of Loch Ness, Scotland: implications for the deglaciation of the Moray Firth Ice Stream, British-Irish Ice Sheet. Journal of Quaternary Science, 27(2), 221-232. https://doi.org/10.1002/jqs.1538
| Journal Article Type | Article |
|---|---|
| Publication Date | Feb 1, 2012 |
| Deposit Date | Feb 13, 2012 |
| Journal | Journal of Quaternary Science |
| Print ISSN | 0267-8179 |
| Electronic ISSN | 1099-1417 |
| Publisher | Wiley |
| Peer Reviewed | Peer Reviewed |
| Volume | 27 |
| Issue | 2 |
| Pages | 221-232 |
| DOI | https://doi.org/10.1002/jqs.1538 |
| Keywords | Loch Ness, Geophysical surveys, Jökulhlaup, Deglaciation, Proglacial. |