A study of the superficial deposits in upper Weardale

Abstract

The geomorphology of the upper reaches of the River Wear Valley has been based on Individual assessments of the complex topography of the area. Evaluation of the superficial deposits as a method of understanding the area, has so far been limited to subjective assessment. In this study a technique recently developed in sedimentary petrology is applied to samples of the suite of deposits existing in Upper Weardale. Two samples are considered, one, a purposive sample chosen to "represent" the deposits of the region for an initial evaluation of the technique, the other sample, a random sample, to permit general conclusions about the nature of the deposits existing in that area. Analysis of the particle-size distribution of the sediments obtained in each sample gives a basis for conclusions about the representative nature of both purposive and random samples. Factor Analysis of the particle-size data gives similar results for each body of data and the Factor analyses of all data as a single unit demonstrates an equal consistency. Consideration of the nature of the four factors produced in this way leads to their tentative identification as the products of glacial action, water-washing processes, rock decomposition and gelifluction. This tentative identification is reinforced by the statistically significant trend surface patterns which emerge from further data analysis. In the final section all other evidence is considered together with the results obtained from data analysis. The conclusions about the geomorphological history are compatible with the evidence considered by previous workers, although the conclusion that the whole area was over-ridden by ice is a departure from the commonly-held view. Conclusions of a methodological nature concerning the wider application of these techniques to complex suites of deposits are also formulated.