Skip to main content

The Islands of Islay, Jura, Colonsay, Tiree and Coll

  • Chapter
  • First Online:
Landscapes and Landforms of Scotland

Part of the book series: World Geomorphological Landscapes ((WGLC))

  • 1603 Accesses

Abstract

The Hebridean islands of Islay, Jura and Colonsay are mainly composed of Neoproterozoic metasedimentary rocks of the Dalradian supergroup, whereas Tiree and Coll are underlain by Archaean rocks of the Lewisian Gneiss Complex. Most of the terrain is low-lying; only the three peaks of the Paps of Jura exceed 600 m. Successive episodes of ice-sheet glaciation have produced areas of ice-moulded topography, and retreat of the last (Late Devensian) ice sheet was accompanied by the deposition of outwash deposits and moraines, including the longest medial moraine in Scotland. The most impressive and internationally renowned landforms on the islands are those related to coastal erosion and deposition: high-level glacimarine deposits; ancient (possibly Pliocene) glaciated strandflat; extensive areas of high rock platforms and intertidal platforms that demonstrably pre-date the last ice sheet; an isostatically tilted rock platform that formed under Lateglacial periglacial conditions; magnificent flights of Lateglacial shingle ridges extending up to 37 m above present sea level; and lower Holocene raised beaches locally backed by sand dunes and areas of machair (calcareous aeolian shell-sand) deposits. Inland, the quartzite flanks of the Paps of Jura are scarred by paraglacial landslides possibly triggered by seismic activity that accompanied rapid glacio-isostatic uplift.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 149.00
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 199.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info
Hardcover Book
USD 199.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

References

  • Ballantyne CK (1999) Maximum altitude of Late Devensian glaciation on the Isle of Mull and Isle of Jura. Scot J Geol 35:97–106

    Article  Google Scholar 

  • Ballantyne CK (2019) After the ice: Lateglacial and Holocene landforms and landscape evolution in Scotland. Earth Env Trans R Soc Edinb 110:133–171

    Google Scholar 

  • Ballantyne CK, Dawson AG (2019) Sgriob na Caillich: a landslide-sourced medial moraine on the Isle of Jura. Scot Geogr J 135:139–149

    Google Scholar 

  • Ballantyne CK, Small D (2019) The Last Scottish Ice Sheet. Earth Env Sci Trans R Soc Edinb 110:93–131

    Google Scholar 

  • Ballantyne CK, Sandeman GF, Stone JO, Wilson P (2014a) Rock-slope failure following Late Pleistocene deglaciation on tectonically stable mountainous terrain. Quat Sci Rev 86:144–157

    Article  Google Scholar 

  • Ballantyne CK, Wilson P, Gheorghiu DM, Rodés À (2014b) Enhanced rock-slope failure following ice-sheet deglaciation: timing and causes. Earth Surf Proc Landf 39:900–913

    Article  Google Scholar 

  • Benn DI, Dawson AG (1987) A Devensian glaciomarine sequence in western Islay, Inner Hebrides. Scot J Geol 23:175–187

    Article  Google Scholar 

  • Baltzer A, Bates R, Mokeddem Z et al (2010) Using seismic facies and pollen analyses to evaluate climatically-driven change in a Scottish sea loch (fjord) over the last 20 ka. Geol Soc Lond Spec Publ 334:355–369

    Article  Google Scholar 

  • Callard SL, Ó Cofaigh C, Benetti S et al (2018) Extent and retreat history of the Barra Fan Ice Stream offshore western Scotland and northern Ireland during the last glaciation. Quat Sci Rev 201:280–302

    Article  Google Scholar 

  • Dawson AG (1977) A fossil rock glacier in Jura. Scot J Geol 13:37–41

    Article  Google Scholar 

  • Dawson AG (1980a) Shore erosion by frost: an example from the Scottish Lateglacial. In: Lowe JJ, Gray JM, Robinson JE (eds) Studies in the Lateglacial of NW Europe. Pergamon Press, Oxford, pp 45–53

    Google Scholar 

  • Dawson AG (1980b) The low rock platform in western Scotland. Proc Geol Assoc 91:339–344

    Article  Google Scholar 

  • Dawson AG (1982) Lateglacial sea-level changes and ice limits in Islay, Jura and Scarba, Scottish Inner Hebrides. Scot J Geol 18:253–265

    Article  Google Scholar 

  • Dawson AG (1993a) Northern Islay. In Gordon JE, Sutherland DG (eds) The Quaternary of Scotland. Geological Conservation Review Series 6. Chapman and Hall, London, pp 378–382

    Google Scholar 

  • Dawson AG (1993b) West Coast of Jura. In Gordon JE, Sutherland DG (eds) The Quaternary of Scotland. Geological Conservation Review Series 6. Chapman and Hall, London, pp 382–387

    Google Scholar 

  • Dawson AG (1994) Strandflat development and Quaternary shorelines on Tiree and Coll, Scottish Hebrides. J Quat Sci 9:349–356

    Article  Google Scholar 

  • Dawson AG, Benn DI, Dawson S (1997a) Late Quaternary glaciomarine sedimentation in the Rhinns of Islay. In: Dawson AG, Dawson S (eds) Quaternary of Islay and Jura: field guide. Quaternary Research Association, Cambridge, pp 66–77

    Google Scholar 

  • Dawson AG, Dawson S, Foster IDL et al (1997b) Lateglacial relative sea level changes, Ruantallain—Shian Bay, western Jura. In: Dawson AG, Dawson S (eds) Quaternary of Islay and Jura: field guide. Quaternary Research Association, Cambridge, pp 17–40

    Google Scholar 

  • Dawson AG, Dawson S, Mighall TM et al (2001) Intertidal peat deposits and early Holocene relative sea-level changes, Traigh Eileraig, Isle of Coll, Scottish Hebrides. Scot J Geol 37:11–18

    Article  Google Scholar 

  • Dawson AG, Elliott L, Mayewski P et al (2003) Late-Holocene North Atlantic climate ‘seesaws’, storminess changes and Greenland ice sheet (GISP2) palaeoclimates. The Holocene 13:381–392

    Article  Google Scholar 

  • Dawson AG, Dawson S, Cooper JAG et al (2013) A Pliocene age and origin for the strandflat of the Western Isles of Scotland: a speculative hypothesis. Geol Mag 150:360–366

    Article  Google Scholar 

  • Dawson S, Dawson AG, Edwards KJ (1998) Rapid Holocene relative sea-level changes in Gruinart, Isle of Islay, Scottish Inner Hebrides. The Holocene 8:183–195

    Article  Google Scholar 

  • Dove D, Arosio R, Finlayson A et al (2015) Submarine glacial landforms record Late Pleistocene ice-sheet dynamics, Inner Hebrides, Scotland. Quat Sci Rev 12:76–90

    Article  Google Scholar 

  • Fabel D, Ballantyne CK, Xu S (2012) Trimlines, blockfields, mountain-top erratics and the vertical dimensions of the last British-Irish Ice Sheet in NW Scotland. Quat Sci Rev 55:91–102

    Article  Google Scholar 

  • Fyfe JA, Long D, Evans D (1993) The geology of the Malin-Hebrides sea area. British Geological Survey, UK Offshore Regional Rept. HMSO, London

    Google Scholar 

  • Hansom JD (2003) Loch Gruinart, Islay, Argyll and Bute. In: May V, Hansom JD (eds) Coastal geomorphology of Great Britain. Geological Conservation Review Series 28. Joint Nature Conservancy Committee, Peterborough, pp 556–561

    Google Scholar 

  • Levell BK, Johnson HD, Collins DS, Van Cappelle M (2020) Deposition and preservation of fluvio-tidal shallow-marine sandstones: a re-evaluation of the Neoproterozoic Jura Quartzite (western Scotland). Sedimentology 67:173–206

    Article  Google Scholar 

  • McCabe AM, Haynes JR, Macmillan NF (1986) Late-Pleistocene tidewater glaciers and glaciomarine sequences from north County Mayo, Republic of Ireland. J Quat Sci 1:73–84

    Article  Google Scholar 

  • McCabe AM, Clark PU, Clark J (2007) Radiocarbon constraints on the history of the western Irish ice sheet prior to the last glacial maximum. Geology 35:147–150

    Article  Google Scholar 

  • Park RG, Stewart AD, Wright DT (2002) The Hebridean terrane. In: Trewin NH (ed) The geology of Scotland, 4th edn. The Geological Society, London, pp 45–80

    Google Scholar 

  • Peacock JD (2008) Late Devensian palaeoenvironmental changes in the sea area adjacent to Islay, SW Scotland: implications for the deglacial history of the island. Scot J Geol 44:183–190

    Article  Google Scholar 

  • Peacock JD, Merritt JW (1997) The Tynacoille-Blackrock ridge: a possible ice front position for glacier ice occupying Loch Indaal. In: Dawson AG, Dawson S (eds) Quaternary of Islay and Jura: field guide. Quaternary Research Association, Cambridge, pp 56–59

    Google Scholar 

  • Ritchie W (1976) The meaning and definition of machair. Trans Bot Soc Edinb 42:431–440

    Article  Google Scholar 

  • Shennan I, Bradley SL, Edwards R (2018) Relative sea level changes and crustal movements in Britain and Ireland since the last glacial maximum. Quat Sci Rev 188:143–159

    Article  Google Scholar 

  • Sissons JB (1974) Lateglacial marine erosion in Scotland. Boreas 3:41–48

    Article  Google Scholar 

  • Sissons JB (1981) British shore platforms and ice sheets. Nature 291:473–475

    Article  Google Scholar 

  • Sissons JB (1982) The so-called high ‘interglacial’ rock shoreline of western Scotland. Trans Inst Br Geogr 7:205–216

    Article  Google Scholar 

  • Sissons JB (1983) The Quaternary geomorphology of the Inner Hebrides: a review and reassessment. Proc Geol Assoc 94:165–175

    Article  Google Scholar 

  • Small D, Benetti S, Dove D et al (2017) Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21–16 ka. Quat Sci Rev 167:30–46

    Article  Google Scholar 

  • Smith DE, Hunt N, Firth CR et al (2012) Patterns of Holocene sea-level change in the North of Britain and Ireland. Quat Sci Rev 54:58–76

    Article  Google Scholar 

  • Smith DE, Barlow NLM, Bradley SL et al (2019) Quaternary sea level change in Scotland. Earth Env Sci Trans R Soc Edinb 110:219–256

    Google Scholar 

  • Stephenson D, Gould D (1995) British regional geology: the Grampian Highlands, 4th edn. HMSO, London

    Google Scholar 

  • Sutherland DG (1981) The high-level marine shell beds of Scotland and the build-up of the last Scottish ice-sheet. Boreas 10:247–254

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Alastair G. Dawson .

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 2021 Springer Nature Switzerland AG

About this chapter

Check for updates. Verify currency and authenticity via CrossMark

Cite this chapter

Dawson, A.G., Ballantyne, C.K. (2021). The Islands of Islay, Jura, Colonsay, Tiree and Coll. In: Ballantyne, C.K., Gordon, J.E. (eds) Landscapes and Landforms of Scotland. World Geomorphological Landscapes. Springer, Cham. https://doi.org/10.1007/978-3-030-71246-4_11

Download citation

Publish with us

Policies and ethics