Fossilization

Foreword ix
Bruno DAVID

Acknowledgments xiii

Chapter 1 General Points 1

1.1 Fossilization: a phenomenon that is always exceptional 1

1.2 The main processes of fossilization 3

1.2.1 Preservation of the endo- or exoskeletal elements 7

1.2.2 Formation of replicas or countermolds 8

1.2.3 Formation of internal molds 9

1.2.4 Case study: geode formation 10

1.3 The concept of a Lagerst¤tten 13

Chapter 2 Diversity of Types of Mineralization 17

2.1 Silicification 17

2.1.1 Primary silicification 18

2.1.2 Secondary silicification 28

2.2 Carbonization of plants and compressions of cuticles 43

2.2.1 Carbonification due to anoxia 44

2.2.2 Carbonization in connection with forest fires 44

2.2.3 Biogeochemical carbonization (also known as âdiagenetic carbonizationâ) 46

2.2.4 Plant compressions 49

2.2.5 Imprints and casts 53

2.3 Carbonatizations and calcitic crystallizations 55

2.3.1 Carbonatization by encrusting and impregnation 55

2.3.2 Carbonatization by percolation and recrystallization 58

2.3.3 Geodes and calcitic outgrowths 61

2.3.4 Crystalline fossils formed of carbonates 65

2.4 Pyritization, limonitization and siderite 67

2.4.1 Pyritization 67

2.4.2 Fossils made of iron oxides or hydroxides 80

2.4.3 Siderite nodules 82

2.5 Amberization 84

2.5.1 Copal 85

2.5.2 Amber 86

2.6 Sulfatization (gypsification and mineralization as barite) 92

2.6.1 Gypsification 93

2.6.2 Mineralization to barite 94

2.7 Phosphatization 95

2.7.1 Phosphateous nodules 95

2.7.2 Phosphorites 96

2.7.3 Crystalline phosphate fossils 97

2.8 Bituminous facies 99

Chapter 3 Remarkable Cases and Fossiliferous Contexts 105

3.1 Burial in fine, layered mud 106

3.1.1 The role of microbial mats in Precambrian and Cambrian shales 106

3.1.2 The role of microbial or algal mats in pelites and lithographic limestones 108

3.1.3 Anoxia of laminar clays bearing plants 112

3.1.4 Diatomites 115

3.2 Accumulations of teeth 118

3.3 Bone beds 121

3.4 Fossilized tracks and trackways 123

3.5 Fossils with anatomical connections 128

3.6 Eggs and trophic traces (bite marks, galls, regurgitations and coprolites) 132

3.7 Land-based palynomorphs: spores and pollen grains 140

3.8 Aquatic palynomorphs 145

3.9 Aquatic microfossils: algae, foraminifera and ostracods 148

Chapter 4 Molecular Preservation 159

4.1 Color fossilization 159

4.1.1 Fossils with preserved colors 160

4.1.2 Fossils where the colors are absent, but can be revealed 165

4.2 Fossilization of the original chemical compositions 166

4.3 Fossilized DNA 167

Conclusion 173

References 175

List of Figures 201

List of Plates 203

List of Authors 209

Index 211