No description available.

No description available.

No description available.

No description available.

The well-preserved record of glacial sediment-landform assemblages in Scotland provides an excellent opportunity to reconstruct the extent and style of former glaciation. Despite a concerted research effort, there remain areas where glacial events are poorly constrained. This is exemplified by the Gaick, a dissected plateau in the Central Grampians, which has proven to be an enigmatic and controversial area. Previously-proposed models fail to adequately explain glacial events in the area, partly due to a paucity of detailed geomorphological, chronological and sedimentological investigations. This thesis presents the results of systematic studies of the sediment-landform record in the Gaick. These investigations, combined with the application of morphostratigraphic principles, have elucidated sediment-landform signatures indicative of multiple glacier fluctuations, specifically (i) interactions of local and regional ice lobes following unzipping during ice sheet deglaciation, (ii) a major stillstand of an extensive pre-Younger Dryas plateau icefield, and (iii) spatiallyrestricted plateau icefield glaciation during the Younger Dryas. The sediment-landform record also suggests a two-phased Younger Dryas advance, as has been found elsewhere in Scotland. The sediment-landform evidence was used to produce palaeoglaciological reconstructions for the three glacial phases. The clarity and completeness of the geomorphological record relating to the Younger Dryas, combined with ice surface profile modelling, allowed the three-dimensional reconstruction of a ~42 km2 plateau icefield. This reconstruction yielded an equilibrium line altitude value of 751 ± 46 m, which was used to derive a sea-level equivalent precipitation estimate of 826 ± 331 mm a-1. Taken together with glacier-derived precipitation estimates from across Scotland, this indicates a strong west-east precipitation gradient during the Younger Dryas. This thesis arrives at a more nuanced understanding of former glaciation in the Gaick, resolving discrepancies with previous conceptual models. In particular, this thesis demonstrates that the Gaick was an important ice dispersal centre throughout the Last Glacial-Interglacial Transition.

The area studied is part of Wester Ross, north-west Scotland, and includes the Applecross Peninsula and the land to the east between Strathcarron and Glen Torridon. Mapping of glacial landforms involved study of aerial photographs and subsequent field work. Evidence was found for the existence of two ice caps and five separate coire glaciers during the Loch Lomond Readvance, their various termini being represented today by clear lateral and end moraines at fourteen out of twenty-five locations. In nine cases, multiple lateral and/or end moraines suggest fluctuation of these ice margins during the Stadial maximum. An earlier stage of glaciation not related to the Late-Devensian ice-sheet maximum is represented by a single moraine and glacial striae. It is believed that this substage probably occurred between 18,000 and 14,000 years ago. Former sea-level changes were investigated by accurate mapping and instrumental levelling of raised coastal features. Three major periods of formation were identified :- 1. A pre-glacial or interglacial stage, evidenced by a highlevel rock platform at 32 to 37 m O.D.; 2. Raised beaches and deltas lying between 21 and 28 m O.D. relating to a period of very early Lateglacial deglaciation; 3. Postglacial features lying below about 10 m O.D. Pollen analysis of core sequences from two sites helped confirm the Loch Lomond Readvance age of the end moraines in Strath a' Bhathaich and to elucidate the history of vegetational development in the area between ca. 13,000 and 9,000 B.P. The Lateglacial pollen diagram indicates early development of a treeless Empetrum- dominated landscape that reverted during the Stadial to tundra-like conditions with a floristically-poor, open vegetation. Both Postglacial diagrams indicate a rapid recovery in early Postglacial times, with the return of pioneer species shortly superceded by a closed vegetation, and then by immigration of birch trees, and the establishment of a mixed birch-hazel woodland.

Thèse 3e cycle--Géologie--Dijon. / Bibliogr. p. 99-108 . Index.

Th. Univ.--Géol.--Dijon, 1990. / Résumé en français et en anglais. Bibliogr. p. 121-124.

No description available.

A multi-disciplinary, high resolution, geophysical investigation of a Scottish Sea loch has facilitated both the reconstruction of a detailed late Quaternary para-stratigraphic model and the critical assessment of the acquisition and analytical methodologies most appropriate for the study of submerged palaeo-glaciomarine environments. Loch Ainort, situated on the eastern coast of the Isle of Skye, has been surveyed using a 192 kHz echosounder, a 400 kHz side scan sonar and a 3.5 kHz sub-bottom profiler. Lithological calibration was provided by the analysis of both in situ core data and extant terrestrial data sets. It is proposed that for the effective reconstruction of these and any other nearshore palaeo-environments a multi-disciplinary geophysical approach is essential. The critical control on success is the adherence, during interpretation, to a single unifying seismo-analytical framework. The seismo-stratigraphical analysis technique has been adapted for high- resolution work in order to provide this rigid framework. Objective descriptive analysis of the seismic traces provides a "seismic para-stratigraphy" which when combined with lithological data is used to construct a "composite para-stratigraphy". This is a process based, litho-stratigraphic interpretation that, by virtue of the detailed spatial extent afforded it by geophysical data, can be placed in a wider environmental context. The composite para-stratigraphy for the Loch Ainort basin is dominated by Loch Lomond Stadial glacial activity. Terminal and readvance limits are identified at several localities within the basin. Variable morphological styles of the glacial sequences show that deglaciation occurred in two distinct, climatically controlled, phases. The first marked by a fluctuating ice margin and the second by uninterrupted retreat and in situ ice stagnation. Sub-aerially induced debris flows occur during the initial paraglacial phase but stabilisation of exposed slopes restricts this input and rapid sedimentation of fines from sediment-rich meltwaters becomes dominant. Modern fjordic sedimentation develops after the disappearance of glacier ice.