Clapperton, Chalmers Moyes

2018-05-14T10:11:41Z

2018-05-14T10:11:41Z

1967

Those parts of the east Cheviot area appearing on vertical aerial photographs (scale approximately 1:10,000) held by the Scottish Development Department were studied stereoscopically as a prelude to work on the ground. The glacial landforms were mapped on a transparent overlay and then transferred to Six -inch maps (Ordnance Survey Provisional Edition) after approximate corrections for scale and distortion had been made using a Grant Projector. The drift boundaries published by the Geological Survey on the One -inch Drift maps of the area were copied and inserted on the Six -inch maps. The latter were taken into the field so that amendments could be made where necessary as the entire area was systematically investigated on foot. Since it was considered necessary to produce accurately levelled profiles on one of the more extensive landforms, a Watts microptic level (SL100) was used. All of the natural and artificial sections, together with the majority of minor exposures were systematically inspected to establish the nature of the drift and of the underlying bedrock. Since the sections are generally poor and small in number, a 3 -foot soil auger was used to provide supplementary drift information in certain places, and all available bore -hole records for the area were consulted. Where good till sections were exposed in sites that appear to be relatively undisturbed by mass movements, the preferred dip and orientation of stones were measured with a Suunto compass in an attempt to establish the formier directions of ice movement. The following procedure was adopted. Sites were chosen at least 3 feet below the ground surface, and after a vertical face had been cleared, a trench was dug inwards for at least one foot. This was to avoid all possible interference by plants and animals. At every site the dip and compass orientation of 100 stones were measured and recorded. Each stone selected for measurement possessed axes that were in the ratio of at least 1:2. Stones smaller than 1 cm. and larger than 20 cros. were avoided. Contiguous particles and particles with long areas dipping in excess of 600 were rejected, as were those in the vicinity of large boulders. The lithology and shape of each stone were also recorded. The measurements were plotted on polar equal nets (Figure 1.1, Chapter 1), on which the radial scale represents dip and the circumferential scale azimuth (Kirby 1961). The resulting scatter diagrams of axial plots give a good visual impression of the fabric characteristics. The analysis of peat layers occurring in close juxtaposition with fluvioglacial phenomena necessitated techniques of investigation beyond the writer's scope. For this reason, pollen analyses of the peat were undertaken by S. E. Durno who also produced the pollen diagram presented with this thesis. Although levelling and fabric analyses provided useful information, it should be emphasised that the majority of conclusions reached in the following chapters are based essentially on the analysis of morphological maps. The density of fluvioglacial phenomena in many parts of the east Cheviot area is so great that a valid interpretation of the deglaciation could not have been attempted if the complex interrelationships of the landforms had not first been plotted on the Six -inch scale. The landforms were later also plotted on the scale of 1 :25,000, so that the overall patterns could be more readily discerned. The latter are presented in the map pocket accompanying this volume and are referred to throughout the text as Maps 1 to 11. The list of symbols used on these maps is also located in the map pocket. Where it has been necessary to illustrate the landforms in more detail, figures drawn to a scale larger than 1 :25,000 and photographs are included with the text.

http://hdl.handle.net/1842/29678

The University of Edinburgh

Annexe Thesis Digitisation Project 2018 Block 18

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Deglaciation of the East Cheviot area, Northumberland

The deglaciation of the East Cheviot area, Northumberland

Thesis or Dissertation

Doctoral

PhD Doctor of Philosophy