A THESIS Entitled the INFLUENCE of ENVIRONMENT on REGIONAL
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A THESIS entitled THE INFLUENCE OF ENVIRONMENT ON REGIONAL GEOCHEMICAL PATTERNS IN NORTHERN IRELAND. Submitted for the degree of DOCTOR OF PHILOSOPHY in the FACULTY OF SCIENCE OF THE UNIVERSITY OF LONDON by CHARLES ROY MORTON BUTT. Royal School of Mines, February, 1971. -Imperial College. i. ABSTRACT 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 10 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. TABLE OF CCNTENTS 210- ABSTRACT. i. LIST OF TABLES viii. LIST OF FIGURES. x. ACKNOWLEDGEMENTS, xiii. CHAPTER ONE APPLICATIONS OF REGIONAL GEOCHEMICAL RECONNAISSANCE SURVEYS. 1.1 INTRODUCTION, 1 1.2 SAMPLE REPRESENTIVITY. 2 1.3 METAL DISPERSION. 14.31 The secondary environment. 3 1.32 Physical fractionation. 3 1.33 Chemical fractionation. 4 1.34 Dispersion patterns. 6 1.4 APPLICATION OF REGIONAL GEOCHEMICAL RECONNAISSANCE IN MINERAL EXPLORATION. 1.4.1 Introduction. 6 1.42 Exploration in glaciated terrain. 7 1.43 Syngenetic soil anomalies. 8 1.44 Epigenetic soil anomalies. 10 1.4.5 Stream sediment reconnaissance surveys. 12 1.5 APPLICATIONS OF REGIONAL GEOCHEMICAL RECONNAISSANCE IN AGRICULTURE. 14 1.6 APPLICATIONS IN FUND,AN AL GEOLOGY. 19 1.7 INFLUENCE OF THE SECONDARY ENVIRONMENT. 21 1.8 CONCLUSIONS. 23 1.9 OBJECT AND PRESENTATION OF THE CURRENT REASEARCH. 24. CHAPTER TVTO THE TYRONE AREA AND ITS REGIONAL SETTING. 2.1 LOCATION OF THE TYRONE AREA. 26 2.2 PRE-QUATERNARY GEOLOGY. 2.21 General. 26 2.22 North of Ireland. 26 2.23 Tyrone area. 27 2.24 Mineralisation andAining_histoIx. 2.241 Introduction. 31 2.242 Down - Armagh. 31 2.24.3 Minor occurrences of the Midland Valley. 32 2.3 QUATERNARY GEOLOGY. 2.31 North of Ireland 33 2.32 Tyrone area. 34 2.4 PHYSIOGRAPHY AND DRAINAGE. 35 2.5 CLIMATE. 37 2.6 SOILS OF THE TYRONE AREA. 38 2.7 AGRICULTURE. 2.71 Farming practice. 40 2.72 Known nutritional disorders. 41 CHAPTER THREE REGIONAL GEOCHEMICAL RECONNAISSANCE OF THE TYRONE AREA. 3.1 SAMPLE COLLECTION AND PREPARATION. 44 3.2 ANALYSES OF SAMPLES FROM THE TYRONE AREA. 45 3.3 RESULTS OF THE RECONNAISSANCE SURVEY OF THE TYRONE AREA. Raze. 3.31 introduction. L,-8 3.32 Distribution of stream precipitates. 48 3.33 Distribution of metals. 3.331 Manganese. 49 3.332 Iron. 51 3.333 Cobalt. 52 3.334 Zinc. 53 3.335 Lead. 54 3.336 Copper. 54 3.337 Molybdenum. 55 3.4 PATTERNS RELATED TO THE SECONDARY ENVIRONMENT. 55 3.5 PATTERNS RELATED TO BEDROCK GEOLOGY. 3.51 General. 58 3.52 Lower and Upper Dalradian. 58 3.53 Upper Dalradian. 59 3.54 Siluro-Ordovician. 61 3.55 Old Red Sandstone. 61 3.56 Lower Carboniferous. 61 3.57 Caip Limestone. 62 3.58 Permo-Trias. 62 3.6 PATTERNS OF SIGNIFICANCE TO MINERAL EXPLORATION. 3.61 Introduction. 62 3.62 Keady area. 65 3.63 Midland Valley. 3.631 Fintona. 66 3.632 Lisbellaw. 66 3.633 Low Sperrins. 67 3.634 Derg Valley. 67 3.635 Glenelly Valley. 69 3.636 Dromore. 69 3.637 Conclusion. 69 3.7 PATTERNS OF SIGNIFICANCE TO AGRICULTURE. 3.71 Introduction. 70 3.72 Deficiency conditions. 3.721 Copper. 71 3.722 Cobalt, manganese and zinc. 71 3.723 Multi-element deficiencies. 72 3.72 Toxicity conditions. 3.731 Molybdenum. 72 37:32 Lead and zinc. 73 3.74 Hypomagnesaemia. 73 3.8 STREAM CONTAMINATION. 74 3.9 PROBLEMS SELECTED FOR FURTHER INVESTIGATION. 3.91 Mineral Exploration 75 3.92 Agriculture 75 3.93 Soil chemistry. 76 CHAPTER FOUR GEOCHEMICAL ANOMALIES RELATED TO MINERALISATION. 4.1 INTRODUCTION. 77 4.2 SAMPLING AND ANALYSIS. 4.21 Sampling. 77 4.22 Field analysis. 78 4.23 Laboratory analysis. 79 4.3 KEADY AREA 4.31 Location and topographic setting 80 iv. 4.32 Geology and mineralisation. 80 4.33 Local drainage survey. 81 4.34 Mullaghdcy drainage anomaly. 82 4.4' BARONS COURT, NEWTOWNSTEWART. 4.41 Location and topographic setting. 84. 4.42 Geology and mineralisation. 4.421 Geology. 85 4.422 Mineralisation. 85 4.423 Glaciation. 86 4.43 Soils and vegetation. 86 4.44 Drainage and soil anomalies. 4.441 Local drainage survey. 87 4.44? Bessy Bell drainage anomaly. 88 4.443 Manus drainage anomaly. 88 4.44h Manus Wood soil anomaly. 91 4.45 Metal source. 92 4.46 Dispersion mechanism. 93 4.5 CONCLUSIONS. 97 CHAPTER FIVE GEOCHEMICAL PATTERNS OF POSSIBLE AGRICULTURAL SIGNIFICANCE. 5.1 INTRODUCTION. 101 5.2 SAMPLING AND ANALYSIS. 5.21 Sampling. 102 5.22 Sample preparation and analysis. 103 5.3 INVESTIGATIONS INTO AREAS OF RAISED SEDITIENT MOLYBDENUM. 5.31 South Enniskillen. 5.311 Description of area. 103 5.312 Results. 104 5.313 Discussion. 104 5.32 Drumquin. 5.321 Description of area. 106 5.322 Results. 107 5:.323 Dis cussion. 107 5.33 Isolated molybdeniferous sediments. 5.331 Description of areas. 107 5,.332 Results. 107 5.34 Conclusion. 108 5.4 INVESTIGATIONS INTO AREAS OF LOW COPPER AN]) ZINC. 5.41 Introduction. 108 5.42 Preliminary investigations. 5.421 Sampling. 109 5.422 Results of sediment sampling. 109 5.423 Results of soil sampling. 110 5.424 Discussion. 113 5.425 Preliminary conclusions. 120 5.45 Detailed investigations. 5.431 Introduction. 121 5.432 Low-c2pper catchments. 5.4321 Clogherny Glebe, near Beragh, Co. Tyrone. 123 5.4322 Ballyreagh, Tempo, Co. Fermanagh. 128 5.4323 Sion Mills, Co. Londonderry, Clady, Co. Londonderry. 131 5.433 Control catchments. 5.4331 Killin, Mountfield, Co. Tyrone. 133 Peat, 5.4332 Mayne, Mountfield, Co. Tyrone. 135 5.434 Discussion 138 5.5 CONCLUSIONS. 5.51 Interpretation of low-copper stream sediment patterns. 142 5.52 :,E,ricultural significance of the copper and zinc distribution patterns. 144. CHAPTER SIX GEOCHEMICAL PATTERNS RELATED TO THE SECONDARY ENVIRONMEN2. 6.1 INTRODUCTION. 6.11 Statement of the problem. 114-7 6.12 Choice of field areas. 148 6.2 THE CENTRAL THRONE AREA 6.21 Geology. 149 6.22 Soils. 149 6.23 Reconnaissance results. 151 6.3 SAMPLING ANALYSIS 152 6.4 LOW SPERRINS CATCHMENTS. 153 6.41 Field areas. 6.4.11 Camlough. 153 64412 Slievemore. 154 6.42 Structure and metal contents of stream sediments. 6.421 The occurrence of ferromanganese stream precipitates. 154 6.422 Stream sediments at the reconnaissance site. 159 6.423 Iron slime seepages. 161 6.424 Metal associations in stream sediments. 161 6.4.3 Metal contents of soils. 162 6.431 Peaty podzols. 162 6.432 Reclaimed podzols. 165 6.433 Peats and peaty gleys. 167 6.431. Bank soils. 167 6.435 Metal associations in soils. 168 6.44 Metal migration in the soil sequence. 170 6.5 CONTROL CATCHMENTS. 172 6.51 Field areas. 6.511 Clogherny Glebe. 172 6.512 Mayne 173 6.513 Killin 173 6.52 Metal contents of stream sediments. 174 6.53 Metal contents of sous: 6.531 Introduction. 176 6.532 Freely drained brown earths. 180 6.533 Imperfectly drained and gleyed soils. 181 6.534 Peats. 183 6.535 Bank soils. 183 6.536 Metal associations in soils. 134 6.54 Metal migration in the soil sequence. 186 6.6 METAL DISTRIBUTION AND MIGRATION IN THE CONTRASTING ENVIROENIVTS. 187 6.7 CONCLUSIONS. 192 CHAPTER SEVEN MICROMORPHOLOGICAL INVESTIGATIONS OF SOILS. AND SEDIMENTS. 7.1 INTRODUCTION. 7.11 Object of investigations. 200 7.12 Techniques of investigations. 201 vi. Peal. 7.2 SAMPLE COLLECTION AND PREPARATION 7.21 Sample collection,, 202 7.22 Sample preparation. 7.221 Optical microscopy. 203 7.222 Scanning electron microscopy. 204 7.223 Electron probe micro-analysis. 205 7.21+ Diffraction techniques. 206 7.3 LOW SPERRINS CATCH1ENTS. 206 7.31 Soils. 7.311 Introduction. 206 7.312 Parent materLals. 206 7.313 Peaty podzols. 208 7.314 Reclaimed podzols. 209 7.315 Peaty gleys. 210 7.f16 Metal enriched bank soils. 211 7:.'2 Stream sediments. 215 7.4 CONTROL CATCHMENTS. 217 7.41 Soils. 7.4-11 Introduction. 217 7.4.12 Parent.