Tertiary

Late Glacial

Holocene                                               

The Clapperton (1997) curve, comparing Greenland ice core data with possible glacier extent in the Scottish Highlands. During periods of prolonged cold, Ice Sheets form; shorter periods or less intense cold brings Mountain Ice Caps, Mountain Ice Fields and Corrie Glaciers.

Oxygen Isotope curve from deep ocean sediments, showing the approximate ages of the main OI stages.

Late Pleistocene

The period since the last interglacial has seen many rapid and marked shifts in the climate of Scotland. Although the terrestrial stratigraphic record is still poorly understood, there is growing evidence for the existence of major ice masses during several intervals during the Late Pleistocene. Clapperton (1997) has used the Greenland ice core data as an indicator of ice extent in Scotland. His reconstruction suggests that the Northern Highlands would have been covered by ice and snow for much of the last 100 kyr. The extent of ice across peripheral areas like Caithness and Orkney remains unclear.

The main sub-divisions of the Late Pleistocene are based on the marine oxygen isotope record:

  • OI Stage 5e - the last interglacial
  • OI Stage 5d - a cold period
  • OI Stage 5c - a long temperate period
  • OI Stage 5b - a cold period
  • OI Stage 5a - a shorter temperate period
  • OI Stage 4  - a long cold period when ice sheets may have covered much of Scotland
  • OI Stage 3  - a period of cold with brief warm periods, with smaller glaciers
  • OI Stage 2  - a long cold period when the last (Late Devensian) ice sheet covered all of Scotland
  • OI Stage 1  - the Holocene, the current interglacial

The last ice sheet advanced into Caithness after 32 ka. It covered event he highest hills and flowed out into the Pentland Firth to terminate at the edge of the continental shelf. Deglaciation was completed around 15 ka. Glaciers flowing from the inner Moray Firth probably reached Buchan in OISs 4 and 3 so it is likely that Caithness was also at least partly glaciated then.