Soils and Sediments

Clays and soils play an important role in agriculture, environment and mineral deposits. In individual articles, eminent scientists describe the state of the art of this field of research.

1 Clay Minerals in Weathered Rock Materials and in Soils.- 1 Introduction.- 2 Hydrolytic Weathering Processes and Genesis of Secondary Constituents.- 3 Pedological Clay Minerals: Nature and Characterization.- 4 Conclusion.- References.- 2 Calcareous Epigenetic Replacement («Epigénie») in Soils and Calerete Formation.- 1 Introduction.- 2 Vertical and Lateral Development of Calcareous Accumulation.- 3 Isovolumetric Replacement by Calcite.- 4 Genesis,Stability and Instability of Palygorskite.- 5 Occurrences of Calcite and Calerete Formation.- 6 Calcite-Silicate Mineral Assemblages in Calcretes.- 7 Calerete and Geochemistry of Landscapes.- 8 Calcretes and Paleoenvironments.- 9 Conclusions v..- References.- 3 Laterites and Bauxites.- 1 Introduction.- 2 Formation of the Original Bauxites.- 3 Evolution of the Original Bauxites: Formation of Degraded Bauxites.- 4 Mass Balances of the Different Evolutions.- 5 Alteration Rate and Age of Bauxites.- 6 Evolution of the Bauxite Landscapes.- 7 Conclusion.- References.- 4 Geochemical Processes in Tropical Landscapes: Role of the Soil Covers.- 1 Introduction.- 2 Soil Covers in Dynamic Equilibrium.- 3 Soil Covers in Chemical Disequilibrium (Transformation Systems).- 4 Conclusions.- References.- 5 Evolution of Lateritic Manganese Deposits.- 1 Introduction.- 2 Example of the Moanda (Gabon) Sedimentary Manganese Deposit Enriched by Lateritization.- 3 Comparison with Other Manganese Deposits.- 4 Conclusion.- References.- 6 The Lateritic Nickel-Ore Deposits.- 1 Geochemical Characteristics of Nickel.- 2 Nickel-Ore Deposits.- 3 Petrology of Lateritic Weathering Profiles on Ultrabasic Rocks.- 4 Geochemical Interpretation of the Evolution of Weathering Profiles.- 5 Discussion: Role of the Weathering Factors in the Formation of Deposits.- 6Conclusion.- References.- 7 The Behavior of Gold in the Lateritic Alterosphere.- 1 Introduction.- 2 Chemical and Mineralogical Properties of Gold.- 3 The Precambrian Gold Lithosphere and its Weathering.- 4 Gold Behavior in Natural Supergene Systems.- 5 Conclusions and Perspectives.- References.- 8 Comparative Ecology of Two Semi-Arid Regions: the Brazilian Sertäo and the African Sahel.- 1 Introduction.- 2 Ecological Parameters.- 3 Discussion.- 4 Conclusion.- References.- 9 Importance of the Pore Structures During the Weathering Process of Stones in Monuments.- 1 Introduction.- 2 Progressive Understanding of the Alteration of Stones in Monuments.- 3 The First Studies on Sandstones in France.- 4 Alteration Morphologies and Parameters governing their Development.- 5 Pore Structures.- 6 Water Balance and Stone Weathering.- 7 Conclusion.- References.- 10 Continental Silicifications: A Review.- 1 Introduction.- 2 The Geological Data and their Interpretation.- 3 Mechanisms at Work.- 4 Conclusions.- References.- 11 Clay Minerals,Paleoweathering, Paleolandscapes and Climatic Sequences:The Paleogene Continental Deposits in France.- 1 Introduction.- 2 Landscapes and Regoliths at the End of the Cretaceous.- 3 The Siderolithic Discharge.- 4 The Indurated Landscapes.- 5 Pre-Evaporitic Clay Minerals in Restricted Basins.- 6 Geochemical Sequence of Climatic Origin.- 7 Conclusion.- References.- 12 On the Genesis of Sedimentary Apatite and Phosphate-Rich Sediments.- 1 Introduction.- 2 Apatite Synthesis.- 3 Genesis of Sedimentary Apatite.- 4 Genesis of Phosphorites and Phosphate-Rich Sequences.- 5 Conclusion: A Model for Phosphogenesis.- References.- 13 Clay Mineral Sedimentation in the Ocean.- 1 Introduction.- 2 Sedimentary Formatron and Destruction of Clay Minerals.- 3 Detrital Supplyand Diagenesis of Clay Minerals.- 4 Preservation and Destruction of the Paleoenvironmental Record of Marine Sedimentary Clay.- References.- 14 Revisited Isotopic Dating Methods of Sedimentary Minerals for Stratigraphic Purpose.- 1 Introduction.- 2 Some Fundamentals.- 3 Examplesof Isotopie Dating of Clay Minerals.- 4 Isotopie Dating of Non-Clay Minerals.- 5 Conclusion.- References.- 15 Concomitant Alteration of Clay Minerals and Organic Matter during Burial Diagenesis.- 1 Introduction.- 2 Maturation Stages of Organic Matter.- 3 Mineral Alterations.- 4 Conclusions.- References.