Ancient Sedimentary Environments and the Habitats of Living Organisms Introduction to Palaeoecology

I am pleased to be able to introduce this book by Monsieur lean-Claude Gall, firstly because it is a book, secondly because its author has been a colleague for 15 years, and finally because it is a book which demonstrates the growing importance of Palaeobiology. "Because it is a book". I have already commented else­ where on the value which the Earth Science community places on a book. And here I am speaking, not of a thesis or a specialised memoir, which are always precious, but of a manual or text, which draws on the experts in the service of all. In the years preceding and following the Second World War, the number of "books" written by French geologists could be counted on the fingers of one hand. Today I am happy to see that the number of geological "books" is increas­ ing in France, taking the word "geology" in its broadest sense. This I see as a sign of the growth of the Earth Sciences.

One Information Deduced from the Fossils and the Sediment.- 1: Modes of Life.- I. Mobility.- 1. Aquatic Organisms.- a) Benthos.- i) Sessile Benthos.- ii) Vagile Benthos.- iii) Infauna.- b) Nekton.- c) Plankton.- d) Pseudoplankton.- 2. Land Organisms.- a) Movement on Land.- b) Flight.- II. Nutrition.- 1. Autotrophic Organisms.- 2. Microphagous Organisms.- a) Suspension Feeders.- b) Detritus Feeders.- c) Mud Feeders.- 3. Macrophagous Organisms.- a) Herbivores.- b) Carnivores.- c) Saprophages.- d) Parasites.- III. Reproduction.- 1. Asexual Reproduction.- 2. Sexual Reproduction.- IV. Growth.- V. Behaviour.- 2: Constraints on Living Conditions.- I. Nature of the Substrate.- 1. Hard Bottoms.- 2. Soft Bottoms.- II. Salinity.- 1. Marine Organisms.- 2. Brackish Water Organisms.- 3. Freshwater Organisms.- III. Water Turbulence.- IV. Oxygenation of the Water.- V. Bathymetry.- VI. Turbidity of the Water.- VII. Temperature and Climate.- 1. Land Organisms.- a) The Fauna.- b) The Flora.- 2. Aquatic Organisms.- a) Warm Water Organisms.- b) Cold Water Organisms.- 3. Palaeotemperature Measurements.- 4. Seasonal Cyclicity.- 3: Evidence of Biological Activity.- I. Evidence of Reproductive Activity.- 1. Spores and Pollen.- 2. Eggs and Clutches.- a) Invertebrate Eggs and Clutches.- b) Vertebrate Eggs and Clutches.- i) Fish.- ii) Reptiles.- iii) Birds.- c) Reasons for Studying Eggs and Clutches.- II. Evidence of Feeding.- 1. Signs of Predation.- 2. Fossil Excrement.- III. Trails and Burrows (Ichnology).- 1. Dwelling Traces.- 2. Moving and Resting Traces.- a) Moving Traces.- b) Resting Traces.- 3. Feeding Traces.- 4. Reasons for Studying Trace Fossils.- a) Bathymetry.- b) Oxygenation of the Environment.- c) Sedimentation Rate.- d) Cohesion of the Substrate.- 4: The Sediment.- I. Observa tions onSed imentary Particles: Sedimentary Petrology.- 1. Penological Characteristics of the Sediment.- a) Information on Regions Upstream of the Site of Deposition.- i) Source Areas.- ii) Climate.- b) Information About the Environment of Deposition.- i) Redox Potential.- ii) Salinity.- iii) Information from Clay Minerals.- iv) Information from Geochemistry.- c) Information on Diagenetic Changes.- 2. Petrography.- a) Surface Appearance of Quartz Grains.- b) Shape and Roundness of Pebbles.- 3. Grain Size Measurement.- a) Detrital Rocks.- b) Carbonate Rocks.- 4. Particle Distribution.- a) Graded Bedding.- b) Parting Lineation.- c) Pebble Orientation.- d) Pebble Imbrication.- II. Observations on Beds: Stratinomy.- 1. Stratification and Bedding.- a) Stratification.- b) Bedding.- i) Horizontal Bedding.- ii) Cross-Bedding.- iii) Flaser Bedding.- iv) Convolute Bedding.- 2. Sedimentary Structures.- a) Structures on the Top of the Beds.- i) Ridges or Ripple Marks.- ii) Crescent Marks.- b) Structures on the Base of the Bed.- i) Structures Indicating thePhysico-Chemical Environment of the Underlying Bed.- ii) Structures Made by Currents.- iii) Deformation Structures.- c) Structures Within Beds.- 3. Conclusions.- III. Observations at Outcrop: Analysis of Sequences.- 1. The Idealised Normal Sequence.- 2. Lithological Sequences.- a) Positive and Negative Sequences.- b) Sequences Derived from Soils.- 3. Rhythmic Series.- a) Varves.- b) Alternation of Limestones and Marls.- i) Hallam’s Theory of Eustatic Control.- ii) Lombard’s Theory of Gravity Flow.- iii) Climatic Variations.- iv) Diagenetic Origin.- c) Molasse.- d) Flysch.- e) Coal.- 5: Sedimentary Environments.- I. Continental Environments.- 1. Fluviatile Environments.- a) Alluvial Cones.- b) Fluviatile Deposits.- 2. Lacustrine Environments.- 3. Aeolian Sedimentation.- 4. The Glacial Environment.- II. Marine Environments.- 1. The Intertidal Zone or Shoreface.- a) The Sediments.- b) The Organisms.- 2. Neritic Environments.- a) Neritic Environments Subject to Terrigenous Sedimentation.- i) The Sediments.- ii) The Organisms.- b) Neritic Environments with Carbonate Deposition.- c) Reef Environments.- i) The Sediments.- ii) The Organisms.- iii) Environmental Parameters of the Reef.- iv) Zonation of Reefs.- 3. The Ocean.- a) The Sediments.- b) The Organisms.- III. Deltas and Estuaries.- 1. Deltas.- a) The Sediments.- b) The Organisms.- 2. Estuaries.- IV. Lagoons.- 1. The Sediments.- 2. The Organisms.- V. Turbidity Currents.- 1. The Sediments.- 2. The Organisms.- VI. Environments of Deposition of Evaporites.- 1. Lagoons.- 2. Major Marine Platforms.- 3. Precipitation Within the Sediment.- 6: Fossiliferous Horizons.- I. Origin of Fossiliferous Horizons — Taphonomy.- 1. Accumulation of Organisms.- a) Dense Populations.- b) Mass Mortality.- c) Transport.- 2. Burial of Organisms.- 3. Diagenesis.- 4. Classification of Fossiliferous Horizons.- a) Horizons Formed by Concentration.- b) Horizons Formed by Preservation.- II. Associations of Organisms — Palaeosynecology.- 1. Palaeobiocoenoses.- 2. Thanatocoenoses.- a) Orientation of Fossils.- b) Sorting by Size and Weight.- c) State of Preservation.- d) Indicators of Recycling.- e) The Mixture of Floras and Faunas.- III. The Study of Fossiliferous Horizons.- 1. Uniqueness of Palaeoecological Methods.- 2. Collection of Information.- 3. Presentation of Results: Palaeoecological Profiles.- two Reconstruction of Some Ancient Environments.- 7: The Ediacara Fauna.- I. The Sediment.- II. The Fossils.- 1. The Fauna.- a) Benthic Organisms.- b) Nektonic Organisms.- 2. The Flora.- 3. Evidence of Biological Activity.- III. Preservation.- IV. The Environment.- 8: The Old Red Sandstone Continent.- I. The Fluviatile Complex.- 1. The Sediment.- a) Petrology.- b) The Cyclothems.- 2. The Organisms.- a) Vertebrates.- b) The Invertebrates.- c) The Flora.- 3. Fossilisation.- 4. The Environment.- II. The Orcadian Lake.- 1. The Sediment.- a) Petrology.- b) Stratinomy.- i) Bedding.- ii) Sedimentary Structures.- 2. The Fossils.- a) The Fauna.- b) The Flora.- c) Evidence of Biological Activity.- 3. Preservation.- 4. The Environment.- III. The Rhynie Peat Bogs.- 1. The Sediment.- 2. The Fossils.- a) The Fauna.- b) The Flora.- 3. Fossilisation.- 4. The Environment.- IV. Conclusions on the Environments of the Old Red Sandstone Continent.- 9: The Decazeville Coal Basin.- I. The Sediments.- 1. Petrology.- a) Terrigenous Sediments.- b) Plant-Derived Sediments: Coals.- 2. Stratinomy.- a) Bedding.- b) Rhythmic Deposition.- II. The Fossils.- 1. The Flora.- a) Thallophytes.- b) Bryophytes.- c) Pteridophytes.- d) The Prephanerogames.- e) The Phanerogames.- 2. The Fauna.- a) Terrestrial Animals.- b) Aquatic Animals.- III. The Environment.- 1. The Limnic Nature of the Sedimentary Basin.- 2. Sedimentary Processes.- 3. The Climate.- 4. Conclusion.- 10: The Grès à Voltzia Delta.- I. The Sediment.- 1. Petrology.- a) The Sandstones.- b) The Shales.- c) The Carbonates.- 2. Stratinomy.- a) Bedding.- b) Sedimentary Structures.- 3. Geochemistry.- II. The Fossils.- 1. The Fauna.- a) Foraminifera.- b) Coelenterates.- c) Brachiopods.- d) Annelids.- e) Molluscs.- f) Arthropods.- i) Chelicerates.- ii) Crustacea.- iii) Myriapods.- iv) Insects.- g) Fish.- h) Tetrapod Vertebrates.- 2. The Flora.- a) Pteridophytes.- b) Prephanerogames.- c) Phanerogames.- 3. Evidence of Biological Activity.- a) Eggs and Clutches.- b) Coprolites.- c) Trace Fossils.- III. The Environment.- 1. Fluviatile Channels.- 2. Temporary Pools of Water.- a) Water Salinity.- b) The Ephemeral Nature of the Pools.- c) The Hydrodynamic System.- d) Oxygenation.- 3. Littoral Muds.- IV. Fossilisation.- 1. The Plant-Bearing Sandstones.- 2. The Clay Horizons.- a) Palaeobiocoenoses.- b) Mass Mortality of the Aquatic Fauna.- c) Preservation of Organic Matter.- V. Conclusion.- 11: The Reefs of Hoher Göll.- I. Hallstatt Limestones.- 1. The Sediment.- 2. The Fossils.- 3. The Environment.- II. The Dachstein Reef Complex.- 1. The Fore-Reef Zone.- The Sediment.- 2. The Reef.- a) The Sediment.- b) The Organisms.- 3. The Back-Reef Zone.- a) The Proximal Region.- b) The Distal Region.- III. The Hauptdolomit.- IV. Conclusion.