A THESIS Entitled DISPERSION of NICKEL AND
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A THESIS entitled DISPERSION OF NICKEL AND MOLYBDENUM FROM MINERALISATION IN GLACIATED TERRAIN; S. NORWAY Submitted for the degree of DOCTOR OF PHILOSOPHY in the FACULTY OF SCIENCE IN THE UNIVERSITY OF LONDON by RAYMOND BRIAN BAND Royal School of Mines, Imperial College. August, 1969 ABSTRACT A reconnaissance survey conducted over an area of southern Norway containing Ni-Cu and No-Cu mineralis- ation revealed that the metal content of stream sediment samples collected at a density of 1 per 5 sq. miles adequately outlines known areas of mafic bedrock and zones of weak Mo mineralisation. Studies of bedrock geochemistry indicate the Iveland-Evje amphibolite complex to be a composite body resulting from several phases of basic igneous activity. Subeconomic Ni-Cu mineralisation at MgClland is shown to be genetically associated with the youngest, noritic phase. The distribution of Ni and. Cu in soils and peat bogs at N/11prid is described and particular attention paid to the mode of occurrence of anomalous Ni in soils. Soil Ni anomalies are of complex origin and result from both glacial and saline dispersion. The stream sediment Ni anomaly at MfAland is of restricted length and is due principally to the erosion of anomalous soils. Spurious Ni anomalies, occuring in association with high Mn values and resulting from secondary enhancement, complicate the interpretation of stream sediment data. The effect of climatic fluctuations on the Ni content of stream sediments is studied and is shown to be nonsignificant. The distribution of Mo and Cu in bedrock, soil, peat bogs and drainage sediments in the vicinity of Mo-Cu mineralisation at Flottorp is described. Mo anomalies in the soil principally reflect syngenetic dispersion patterns in the parent till, but saline dis- persion is important in the formation of soil Cu anomalies. Anomalous Mo contents persist in the stream sediment 18,000 ft. downstream from mineralisation. Under favourable circumstances anomalous dispersion trains are unaffected by small lakes in the drainage system. Procedures are recommended for use in exploration for Ni and Mo mineralisation in glaciated areas similar to southern Norway. ii CONTENTS ABSTRACT LIST OF TABLES viii LIST OF FIGURES xii INTRODUCTION 1 Previous Work 3 Acknowledgements 6 CHAPTER I. SAMPLING AND ANALYTICAL TECHNIQUES 7 1. SAMPLING 7 (a Stream sediments 7 (b Soil 7 (c Bog 8 Rock 8 Lake sediments 8 f) Water 9 2. SAMPLE PREPARATION 9 Stream sediments, soils and bogs 9 Rocks 9 Na Mineral separation 10 d) Size analysis 11 3. MEASUREMENT OF pH AND Eh 12 (a Surface waters 13 Groundwaters 13 c Soil and bog 13 4, SPECTROGRAPHIC ANALYSIS 14 5. ATOMIC ABSORPTION ANALYSIS 16 (a) Sample attack 16 (i) Hydrofluoric-perchloric acid 16 (ii)Nitric-perchloric acid 17 (b) Determination of Ni, Cu, Co, Fe, Mn, Mg, Zn 20 (i) Procedure 20 (ii)Precision and accuracy 21 iii Determination of Cr 23 Determination of Ca and Sr 26 e) Comparison of spectrographic 27 and atomic absorption data 6. COLORIMETRIC DETERMINATION OF Mo 27 7. Mo IN WATER 29 8, MERCURY ANALYSIS, 30 9. X-RAY DIFFRACTION ANALYSIS 30 CHAPTER II, THE REGIONAL SURVEY 31 1, INTRODUCTION 31 2. DESCRIPTION OF AREA 32 (a) Geology 32 b Mineralisation 33 c Pleistocene geology 36 d Topography 37 (e Climate, soils and vegetation 38 3, REGIONAL SURVEY RESULTS 39 (a) Presentation of data 39 (b) Results Mo 42 Ni 45 Cr 46 Co 47 Cu 47 Mn 48 Zn 49 Fe 49 4. DISCUSSION 50 (a) Geochemical patterns related to 50 bedrock geology (b) Geochemical patterns related to 52 mineralisation (i) Mo 52 (ii) Ni 53 (iii)Cu 54 (c) Geochemical patterns related to 55 glacial dispersion (d) Geochemical patterns related to 57 secondary environment 5, CONCLUSIONS 61 iv Page THE NICKEL ORIENTATION SURVEY 64 CHAPTER III. BEDROCK INVESTIGATIONS 65 1, INTRODUCTION 65 2. GEOLOGY AND MINERALISATION OF THE 66 IVELAND-EVJE AREA (a) Geology 66 ) Amphibolite 66 ii) Massive gabbroic rocks 67 iii)Diorite 68 (b) Ni mineralisation 68 Flat mine 69 ii) M/lland prospect 70 riii) Other prospects 70 (c) Geology of the MgSlland prospect 71 Norite 71 ii) Amphibolite 72 iii)Metagabbro 72 3. RESULTS 74 4. THE DISTRIBUTION OF THE ORE AND 74 ASSOCIATED METALS AT MOLLAND 5. RELATIONSHIP BETWEEN ROCK UNITS AT 78 MOLLAND (a Whole rock data 82 b Mineral separate data 83 Sr/Ca in plagioclase 88 d Evidence for differentiation 91 6, FURTHER EVIDENCE FOR THE MAGMATIC 95 ORIGIN OF THE SULPHIDES (a) Ni in magnetics 96 (b) Distribution coefficient for Ni 98 7c RECONNAISSANCE BEDROCK SAMPLING AS A 100 MINERAL EXPLORATION METHOD C, ECONOMIC POTENTIAL OF THE IVELAND-EVJE 102 MINERALISATION 9, CONCLUSIONS 104 Page CHAPTER IV. OVERBURDEN INVESTIGATIONS 107 1. INTRODUCTION 107 2. SOIL RESULTS 108 Ni and Cu in B horizon 108 b) Distribution of Ni and Cu in 111 soil profiles ' (c) Mechanical analysis and the 114 distribution of metals between size fractions (d) Mineral analysis 118 (i) Size fractions 11 8 (ii)Soil and bedrock 122 (e) Adsorption experiments 126 3. Ni AND Cu IN PEAT 134 4. RECONNAISSANCE SOIL TRAVERSES AT 144 FLAT MINE 5. THE RELATIVE IMPORTANCE OF GLACIAL 146 AND SALINE DISPERSION 6. CONCLUSIONS 149 CHAPTER V. DRAINAGE SEDIMENT INVESTIGATIONS 15. 1. THE DETAILED DRAINAGE SURVEY 156 2 DISPERSION OF Ni IN THE MaLAND 160 DRAINAGE SYSTEM 3. MECHANICAL ANALYSIS AND THE DISTRIB- 162 UTION OF METALS BETWEEN SIZE FRACTIONS 4. REPEAT SAMPLING INVESTIGATION 169 5. SAMPLING ERROR AT ANOMALOUS LOCALITIES 179 Improved analytical technique 182 b) Replicate sampling 183 Analysing a finer size fraction 185 6. CONCLUSIONS 188 vi Page CHAPTER VI. THE FLOTTORP MOLYBDENUM 191 ORIENTATION SURVEY 1. BEDROCK INVESTIGATIONS 192 a) Introduction 192 N) Results 195 i) Background data 195 ii) Data for mineralised zones 196 iii)Effect of weathering on Mo 197 and Cu content of bedrock (c) Discussion - Origin of the 198 Flottorp mineralisation 2. OVERBURDEN INVESTIGATIONS 204 (a) Introduction 204 (b) Results 205 (i) Soil traverse data 205 (ii) Soil profile data 212 (iii)Mo in peat 215 (iv) Mo in surface waters 218 (c) Discussion - The formation of soil 219 and peat anomalies 3. DRAINAGE SEDIMENT INVESTIGATIONS 225 (a) Mo in stream sediment 226 Mo in lake bottom sediments 228 ) Discussion - Dispersion of Mo 231 W through Lake Haland 4. CONCLUSIONS 236 CHAPTER VII. FOLLOW-UP INVESTIGATIONS 243 1. Mo FOLLOW-UP INVESTIGATIONS 243 a Vegusdal 244 b Killand 247 c Grovane 247 2. Ni FOLLOW-UP INVESTIGATIONS 249 (a) Solberg reconnaissance 250 (b) Preliminary follow-up surveys 251 3. CONCLUSIONS 253 vii LaEt CHAPTER VIII. CONCLUSIONS AND RECOMMENDATIONS 255 FOR FUTURE RESEARCH APPENDIX I. REGIONAL SURVEY DATA 273 APPENDIX II. ANALYTICAL DATA FOR WHOLE ROOK 280 AND MINERAL SAMPLES FROM THE NICKEL ORIENTATION SURVEY LIST OF REFERENCES 288 viii LIST OF TABLES No, Title Page 1 Equivalent particle diameter (mm) for mesh 12 sizes used in mechanical analysis 2 Precision data for spectrographic determin- 16 ation of Ni, Cr, Co, Cu, Mn, Zn and Fe203, based on 6 replicate analyses of control samples 7818, 7819 and 7820 3 Ni, Cu, Co, Fe and Mg determined after 19 nitric-perchloric attack on sized hypersthene and hornblende samples 4 Proportion of total metal (HF attack) 20 liberated from sized hypersthene and hornblende samples by nitric-perchloric acid digestion 5 Routine operating conditions used in atomic 22 absorption analysis for Ni, Cu, Co, Fe, Mn, Mg and Zn 6 Calculated precisions at different Ni contents 23 based on 5 replicate analyses 7 Precision data for mineral samples based on 23 5 replicate nalyses 8 Absorbance counts obtained for 5 ug/ml Cr and 25 2% NH4C1 in presence of additives 9 Operating conditions for Cr analysis by 25 atomic absorption 10 Operating conditions for determination of 26 Ca and Sr 11 Analytical precisions for calorimetric deter- 28 mination of Mo, based on replicate analyses 12 Operating conditions for X-ray diffraction 30 analysis 13 Mean values for Cr, Cu, Mn, Ni, Zn and Fe 39 (as Fe203) 14 Average contents of Co, Cr, Cu, Mn, Mo, Ni, 51 Zn and Fe (as Fe 0 ) in acid and basic igneous rocks (Data from2 Hawkes3 and Webb 1962) No. Title Page. 15 Enrichment of Fe, Mn, Co, Zn, Ni, Cu and Mo 60 in areas of secondary enhancement, estimated by comparing the maximum rolling mean contour with the average content of acid igneous rocks 16 (a) Geometric mean values for whole rock analyses 76 16 (b) Values of the Kolmogorov-Smirnov statistic 76 for testing the significances of differences in element distributions between rock types 17 Main features of the bedrock anomalies at 78 M/Slland on Traverses I, II and III 18 (a) Geometric mean values for mineral separate 85 data 18 (b) Values of Kolmogorov-Smirnov statistic for 86 the distribution of metals between minerals 19 Mean Ni contents, KNi values, Mg contents, 102 Ni/Mg ratios and K(Ni/Mg) values for rock types from the Iveland-Evje complex 20 Main features of the B horizon anomalies on 111 Traverses I, III and IV, MX1land 21 Variation in Ni and Cu content with depth 112 in background soil profiles 22 Variation in Ni and Cu content with depth in anomalous soil profiles 23 Distribution of Ni, Cu, Co, Fe and Mn in 116 the constituent size fractions of anomalous and background soils 24 X-ray data for minerals separated from rock 710 samples from the MySlland area 25 Identification of vermiculite and chlorite 121 in size fraction samples (following the method of Dumbleton and West, 1966) 26 Comparison of mean Ni and Cu contents in 125 background B horizon soils and bedrock 27 pH and Eh data for background peat profiles, 135 Traverse III 28 Variation in Ni and Cu content for anomalous 136 peat profiles 29 Variation in Ni and Cu content for 137 background peat profiles x No.