Lecture 3 Flashcards
Types of fossils - physical remnants
Body fossils (e.g., bones, shells, carbonized and permineralized remains)
Moulds and casts
4 main types of fossils that contribute to the ecosystem
Body fossils
Ichnofossils
Geochemistry
Molecular tracers
Types of fossils - evidence of activity
Ichnofossils or trace fossils (e.g., burrows, footprints, coprolites, gastroliths)
Types of fossils - biosignatures
Molecular fossils (e.g., species-specific lipids, DNA)
Geochemistry (Organic C, 13-C, 18-O)
Body fossils
Remains of body parts (original remains)
Examples of body fossils
Mammoth preserved in permafrost
Vertebrate bones
Pollen grains
Carbon films/carbonized films
Permineralized fossils
Moulds
Casts
Ichonology
The study of trace fossils
Types of ichnofossils
Trace fossils
Coprolites
Gastroliths
Implication of ichnofossils
Sedimentary evidence of biological activity (moving, walking, feeding, reproduction, etc.)
Examples of ichnofossils
Burrows in Ordovician sediment in Manitoba formed by movement of invertebrates in seafloor mud
Modern burrows exposed by erosion on a tidal flat
Human footprints preserved in volcanic ash in Italy
Bird footprints in Halifax
Coprolite in Saskatchewan
Coprolite
Fossilized, mineralized dung
Gastroliths AKA?
Stomach stones
Gastroliths
Rocks voluntarily ingested by certain vertebrates species show characteristic shape, polish, and location within skeletons (birds, crocodiles, some dinosaurs)
Molecular tracers
Chemical residues; provide info about the presence of an organism
Geochemistry and ancient life
Elemental and isotopic signature of rocks, sediments or fossils
Lagerstatten meaning
Storage places
Fossil-Lagerstatten
Sedimentary deposits that contain exceptionally abundant or exceptionally well-preserved fossil assemblages
2 types of fossil-lagerstatten
Konzentrat-Lagerstatten
Konservat-Lagerstatten
Konzentrat-Lagerstatten
Immense numbers of fossils are preserved (e.g., cave deposits, bone beds)
What are Konzentrat-Lagerstatten related to?
Abundance in life, and also to rate of sediment deposition
Konservat-Lagerstatte
Quality rather than quantity
Peculiar preservation conditions allowed soft or unmineralized tissues of animals and plants to be preserved
Names of 8 selected Lagerstatte
Ediacara Hills
Mistaken Point
Burgess Shale
Manitoba Lagerstatten
Joggins Formation
Mazon Creek
Solnhofen Limestone
Baltic Amber
Ediacara Hills age
Proterozoic (approx 600 Mya)
Ediacara Hills general location
Australia
Ediacara Hills major fossil types
1st complex multicellular soft-bodied organisms - possibly early invertebrate animals
Ediacara Hills significance
Shallow marine habitat, or deep on the ocean floor
Rapid burial by turbidite flows
Turbidity current
Generated when sediments slide off the edge of the continental shelf
Mistaken Point age
565 Mya - one of the oldest known Ediacaran biotas
Mistaken Point general location
Newfoundland
Mistaken Point significance
Deep-water environments
Ash deposits
Mistaken Point fossil types
Ichnofossils
Burgess Shale age
508 Mya
Burgess Shale general location
BC
Important characteristic of Burgess Shale
Sudden appearance of “shelly fossils”
Burgess Shale fossil type
Submarine cliff - margin of an algal reef –> catastrophic burial in a fine sediment, and deposition on a sea floor deficient in oxygen
What kind of Lagerstatten is the Burgess Shale period-wise?
Cambrian Lagerstatten
Manitoba Lagerstatten age
443 Mya - Ordovician
Manitoba Lagerstatten significance
Restricted lagoon environment
Record of early nearshore marine life: eurypterids (sea scorpions), horseshoe crabs
Joggins Formation location
Nova Scotia
Joggins Formation age
315 Mya - Carboniferous
Joggins Formation major fossil types
Late Carboniferous tropical vegetation, tree trunks
Charcoal accumulations
Early tetrapods (amphibians, reptiles), other animals
Mazon Creek general location
Illinois
Mazon Creek age
310 Mya - Carboniferous
Mazon Creek fossil types
Clay ironstone concretions (unusual type of preservation), jellyfish and sea anenomes
Mazon Creek significance
Late Paleozoic shallow marine, freshwater and terrestrial life in estuary deposits
Nodules
Diagenetic features
Solnhofen Limestone general location
Southern Germany
Solnhofen Limestone age
150 Mya - Jurassic
Solnhofen Limestone significance
Restricted lagoon within a shelf sea
Stagnant waters with high evaporation
Fossils in very fine-grained lithographic limestone
Solnhofen Limestone fossil types
Fish fins, cephalopod with soft tissues, large jellyfish
Baltic amber deposit general location
Russia
Baltic amber fossil types
Amber - fossil resins
Baltic amber significance
May have different botanical affinities, geological ages, chemistry and properties
How does baltic amber deposit so well?
Very fast burial –> no biostratinomic loss
Broad example of a Konservat-Lagerstatte
Permafrost
What does permafrost depend on?
Local climatic conditions
Unlikely to preserve for significant interval of geological time
