Taphonomy (b) - Lecture 5 Flashcards
What 4 key factors dictate the fossilisation bias?
Biomineralisation (hard bodied organisms more likely to be fossilised), Mineralogy (Calcite minerals more likely to be preserved than aragonite), Habitat and Abunndace
What is meant by the term ‘wave base?’
The depth to which a passing wave will cause motion.
What are conditions like above the wave base?
Strong taphonomic effects, ocean bottom agitated and rippled, much information loss
What are conditions like below the wave base?
Ocean bottom undisturbed by waves, less information loss, more likely to be preserved.
In what two ways can ‘selective deposits’ occur?
Selective transport by size or by hydrodynamic processes
What factors evoke durability in shells?
Fine grain size and poorly sorted
Name 4 categories of animals responsible for biophysical and biochemical destruction in the sea.
Borers, Grazers, Browsers and Predators
Why do borers disrupt the sediment?
For feeding (gastropods) and protection (sponges/cyanobacteria)
Give examples of marine grazers.
Gastropods, Chitons, Echinoids and Fish
Give examples of browsers.
Holothurians, burrowing worms and burrowing crustaceans
What does durophagy mean?
Durophagy is the term for describing the eating behavior of animals that consume hard-shelled or exoskeleton bearing organisms, such as corals, shelled mollusks, or crabs.
Where do concentration deposits occur?
Above wave base in rough water
What are conservation deposits?
Places where organic matter and/or full skeletons are preserved
Typically what conditions do conservation deposits occur?
Anoxic, Dysoxic or Hypersaline conditions
Name three different kinds of conservation deposits.
Stagnation deposits (e.g. Hunsruck shale), Obrution deposits (e.g. fossil assemblage that has been preserved by the very rapid burial of intact organisms) and Conservation traps (e.g. amber)
