Guidelines for Analysis and Description of Soil and Regolith Thin Sections

About the Second Edition xi Acknowledgements to the First Edition xiii List of Abbreviations xv 1. Introduction 1 2. Definitions and Historical Review 5 2.1. What is Soil Micromorphology? 5 2.2. Brief Historical Review 6 2.3. Steps of Micromorphological Analysis 9 2.3.1. Sampling 9 2.3.2. Preparation of Thin Sections 10 2.3.3. Analysis and Description of Thin Sections 10 2.3.4. Interpretation and Reporting 10 3. Aspects and Techniques of Thin Section Studies 11 3.1. From a Two-Dimensional Observation to a Three-Dimensional Reality 11 3.1.1. Introduction 11 3.1.2. Transition from Two to Three Dimensions 11 3.1.3. Wedging Effects 17 3.1.4. Minimal Visible Size and Magnification 17 3.1.5. Holmes Effect 18 3.1.6. Orientation 18 3.1.7. Optical Illusion 18 3.2. Microscopic Techniques for Thin Section Studies 19 3.2.1. Introduction 19 3.2.2. Optical Techniques 19 3.2.2.1. Introduction 19 3.2.2.2. Circular Polarized Light 21 3.2.2.3. Dark-field Illumination 21 3.2.2.4. Oblique Incident Light and Dark Ground Incident Light 23 3.2.2.5. Fluorescence Microscopy 24 3.2.2.5.1. Introduction 24 3.2.2.5.2. Equipment 25 3.2.2.5.3. Application 27 3.2.2.6. Cathodoluminescence 29 3.2.2.6.1. Introduction 29 3.2.2.6.2. Equipment 29 3.2.2.6.3. Sample Preparation 30 3.2.2.6.4. Application 30 3.2.3. Selective Extractions 30 3.2.3.1. Introduction 30 3.2.3.2. Extraction of Carbonates 32 3.2.3.3. Extraction of Iron and Manganese Oxyhydrates 33 3.2.3.4. Bleaching of Humic Substances 33 3.2.4. Staining and Spot Tests 34 3.2.4.1. Introduction 34 3.2.4.2. Differential Staining of Anhydrous Alkali-Earth Carbonates 34 3.2.4.2.1. Introduction 34 3.2.4.2.2. Procedure 34 3.2.4.2.3. Application 35 3.2.4.3. Ferruginous Components 36 3.2.4.4. Manganese Oxides and Hydroxides 36 3.2.4.5. Clay Minerals 36 4. Elements of Fabric 37 4.1. Introduction 37 4.2. Concepts of Fabric 38 4.3. Elements of Fabric 41 4.3.1. Introduction 41 4.3.2. Patterns 42 4.3.2.1. Introduction 42 4.3.2.2. Basic Patterns 42 4.3.2.2.1. Basic Distribution Patterns 43 4.3.2.2.2. Basic Orientation Patterns 43 4.3.2.2.3. Orientation Patterns of Clay Particles 45 4.3.2.3. Referred Patterns 48 4.3.2.3.1. Referred Distribution Pattern 48 4.3.2.3.2. Referred Orientation Patterns 49 4.3.2.4. Related Distribution Patterns 49 4.3.2.4.1. General 49 4.3.2.4.2. The c/f related distribution pattern 52 4.3.3. Size 55 4.3.4. Sorting 57 4.3.5. Abundance 57 4.3.6. Shape 59 4.3.6.1. Introduction 59 4.3.6.2. Equidimensionality 61 4.3.6.3. Degree of Roundness and Sphericity 62 4.3.6.4. Surface Roughness and Smoothness 62 4.3.6.5. Boundary 63 4.3.7. Color 64 4.4. Variability within Partial Fabrics 65 4.5. Concepts Used 65 5. Voids, Aggregates and Microstructure 67 5.1. Introduction 67 5.2. Voids 68 5.2.1. Introduction 68 5.2.2. Types of Voids (Fig. 5.1) 69 5.2.3. Size of Poroids 72 5.2.4. Abundance of Voids 73 5.2.5. Roughness and Smoothness of Void Walls 73 5.2.6. Arrangement of Voids 73 5.2.7. Accommodation of Voids 73 5.2.8. Note 75 5.3. Aggregation 77 5.3.1. Introduction 77 5.3.2. Peds 77 5.3.3. Degree of Ped Separation and of Pedality 79 5.3.4. Size of Peds 80 5.3.5. Accommodation 82 5.3.6. Surface Roughness 82 5.3.7. Internal Fabric 82 5.3.8. Ped Arrangement Patterns 82 5.4. Types of Microstructures 83 5.4.1. Introduction 83 5.4.2. Main Types of Microstructure 83 6. Mineral and Organic Constituents 87 6.1. Introduction 87 6.2. Coarse Mineral Components 87 6.2.1. Introduction 87 6.2.1.1. Importance of its Description 87 6.2.1.2. Subdivision 88 6.2.1.3. Important Properties 88 6.2.1.3.1. Size 88 6.2.1.3.2. Shape 88 6.2.1.3.3. Abundance and Frequency 90 6.2.1.3.4. Alteration 90 6.2.2. Single Mineral Grains 90 6.2.3. Compound Mineral Grains and Rock Fragments 100 6.2.4. Inorganic Residues of Biological Origin 103 6.2.4.1. Introduction 103 6.2.4.2. Opaline Components 103 6.2.4.3. Calcium Oxalate Crystals 105 6.2.4.4. Calcium carbonate constituents of biological origin 105 6.2.4.5. Bones and Other Skeletal Tissues 111 6.2.5. Anthropogenic Elements 113 6.3. Description of Fine Mineral Components 115 6.3.1. Importance of its Description 115 6.3.2. Nature 115 6.3.2.1. Color 116 6.3.2.2. Limpidity 117 6.3.2.3. Interference Colors 117 6.3.2.4. Other Characteristics 117 6.3.3. Size 119 6.3.4. Shape 119 6.4. Description of Organic Components 119 6.4.1. Introduction 119 6.4.2. Animal Residues 120 6.4.3. Plant Residues 121 6.4.4. Alteration 125 6.4.4.1. Introduction 125 6.4.4.2. Alteration of Plant Tissues 126 7. Groundmass 127 7.1. Introduction and Definition 127 7.2. Description 128 7.2.1. The Limit Between Coarse and Fine 129 7.2.2. The c/f related Distribution Pattern 130 7.2.3. Coarse Material, Composition and Fabric 130 7.2.4. The Fine Material (Micromass) and Its Fabric 131 7.2.4.1. Introduction and Definition 131 7.2.4.2. Types of b-fabric 133 7.2.4.3. Factors Influencing the Expression of b-Fabrics 138 8. Pedofeatures 143 8.1. Introduction and Definitions 143 8.2. Subdivision of Pedofeatures 144 8.2.1. Introduction 144 8.2.2. Matrix and Intrusive Pedofeatures 144 8.2.3. Morphological Classification of Pedofeatures as Related to their Fabric 148 8.3. Coatings, Hypocoatings and Quasicoatings 149 8.3.1. Introduction 149 8.3.2. Definitions 149 8.3.3. Classification 151 8.3.4. Descriptive Criteria 153 8.4. Infillings 162 8.4.1. Definition 162 8.4.2. Classification 163 8.4.3. Descriptive Criteria 164 8.5. Crystals and Crystal Intergrowths 165 8.5.1. Introduction 165 8.5.2. Definition 167 8.5.3. Classification 167 8.5.4. Descriptive Criteria 167 8.6. Nodules 168 8.6.1. Introduction 168 8.6.2. Definition 169 8.6.3. Classification 169 8.6.3.1. Internal Fabric 169 8.6.3.2. External Morphology 172 8.6.4. Descriptive Criteria 174 8.7. Intercalations 174 8.7.1. Introduction 174 8.7.2. Definition 174 8.7.3. Classification 176 8.7.4. Descriptive Criteria 176 8.8. Excrements 176 8.8.1. Introduction 176 8.8.2. Descriptive Criteria for Excrements of the Mesofauna 177 8.8.2.1. Shape 177 8.8.2.2. Aging 178 8.8.2.3. Other Criteria 179 8.8.3. Descriptive Criteria for Excrements of Larger Animals 182 8.9. Compound Pedofeatures 182 8.10. Complex Pedofeatures 183 8.11. Fragmented, Dissolved and Deformed Pedofeatures 185 9. Making and Presenting Thin Section Description 189 9.1. Introduction 189 9.2. Observation 190 9.3. Artifacts 191 9.4. Description 191 9.4.1. How to Start? 191 9.4.2. Possible Description Schemes 195 9.4.3. Examples 196 9.5. Presentation of Data 197 10. References 201 Appendix: Materials, Light, and the Petrographic Microscope 225 Subject Index 233