The pollen diagrams were divided into individual pollen
assemblage zones which enabled the vegetational record at each site
to be assessed independently. Correlations between the profiles
showed that at the five sites outside the presumed maximal extent of
Loch Lomond Readvance ice, the basal deposits were of Lateglacial
age with pollen spectra indicati ng a milder Interstadial followed by
a harsher Stadial phase. The overlying sediments were found to be
Postglacial in age. At the sites within the mapped Loch Lomond
Readvance limits, only Postglacial deposits were present. The
combined results of pollen analyses, sedimentological and geomorphological
studies suggest the following history of landscape evolution.The Late Devensian ice-sheet, which probably reached its
greatest extent 17,000 to 18,000 radiocarbon years ago, had virtually
disappeared from the Grampian Highlands by ca. 13,000 B. P.
The early Lateglacial pollen spectra at all the sites reflect an initial
period of colonisation by open-habitat taxa on freshly-exposed substrates following ice-sheet decay. After this early phase of vegetational development, the plant cover of that area of the
Grampians to the north and west of the Ben Nevis-Lochnagar
watershed was dominated by Empetrum heaths, while grassland
with juniper, dwarf birch, willow and occasional copses of tree
birch characterised the southern and eastern slopes. Only in the
extreme south of the study area did tree birch become established
in significant numbers during the Interstadial. At ca. 11,000 B. P.,
declining temperatures heralded the onset of colder Stadial conditions with the recrudescence of glacier ice of the Loch Lomond
Readvance, and the break-up of existing plant communities through
increasingly widespread solifluxion. Open-habitat and chionophilous
vegetation proliferated, environmental conditions became increasingly
more severe, and a tundra landscape developed. This phase was
relatively short-lived however, for rapid climatic amelioration at
about 10,000 B. P. saw the final disappearance of glacier ice from
Scotland, the cessation of solifluxion, and the initiation of a plant
succession which culminated in the establishment of climax forest
over much of the area. At that time, mixed woodland covered the
southern and eastern Grampian slopes, while to the north and west
of the Highland watershed, the landscape was one of coniferous
forest.The purpose of the investigation is to present a geographical interpretation of the past environment of part of the
Grampian Highlands between ca. 13,000 and 7000 B. P. The study
is based principally on pollen analysis, but also draws widely on
the results of sedimentological and geomorphologieal investigations.
Six sites were selected for analysis, five of which are situated out¬
side the presumed limits of the Loch Lomond Beadvance, while the
sixth site is located within those mapped limits. Detailed pollen
analyses were carried out on all the profiles, and at three of the
sites, organic carbon content, particle size and alkali cation percentages were also determined. Radiocarbon dates on critical
horizons were obtained from two of the sites
