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Title: The influence of environment on regional geochemical patterns in Northern Ireland
Author: Butt, Charles R.
Awarding Body: University of London
Current Institution: Imperial College London
Date of Award: 1971
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The results are described of a multi-element stream sediment reconnaissance survey in a glaciated area in the west of Northern Ireland. Regional geochemical patterns have been related to variations in metal abundance and to the varying influence of the local environment on metal dispersion. The patterns are considered in terms at their possible significance in geology, mineral exploration, agriculture and soil science. The mechanisms of metal translocation in the soil-sediment system are discussed. There is mostly a good correlation between the metal contents of sediments and soils, particularly in lowland areas and where streams do not have heavy ferromanganese precipitation. However, the correlation can be distorted by fractionation occurring during physical or chemical dispersion. As a result of sorting in streams, the copper contents of active sediments tend to be lower than those of most soils. Consequently, widespread patterns of 5 - 12 ppm Cu do not necessarily delineate areas of possibly copper deficient soils. Strong coincident patterns shown by cobalt, iron, manganese and zinc are related to variations in the phksico-chemical environment, defined by Eh and pH, and to differences in soil fabric and the secondary occurrence of free iron oxides. The metals are mobilized in acid or gleyed soils and reprecipitated under less acid, more oxidizing conditions in the stream channel, hence sediments become greatly enriched where such soils are widespread. Hydromorphic processes of this type have influenced the dispersion of copper, lead and zinc from mineralisation near Ready, Armagh, and Newtownstewart, Tyrone. Elsewhere they have produced false anomalies unrelated to mineralisation. The reconnaissance technique is considered valuable for detecting regional variations in metal abundance, despite the limitations imposed by the fractionation processes. The effects of sorting are minor, whilst severe leaching and strong sediment enrichment are serious only in wet, upland areas.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available