Death and Fossilization Flashcards
Taphonomy
Study of all natural processes that involves an organism after it dies, this includes how it decays, is scavanged by other organisms, becomes fossilized and erodes.
Boat and float
the idea that the carcasse of even large animals can easily float and be transported by shallow and weakly flowing water
Why is finding complete dinosoaur skeletons rare?
They become disarticulated by…
- carnivours likely ate the remains of other dinosaurs
- water currents can carry different portions of a skeleton to different locations
- prolonged exposure to sunlight can weaken and disintegrate the bones
- some skeletons become partcially buried
- skeltons can be trampled by animals
Plastic deformation
occurs when pressure causes the shape of a buried fossil to be changed such that even when pressure is later removed, the fossil does not return to its original shape
What needs to occur for a bone to be fossilized?
The bone needs to be buried.
What type of enviroment is most common for a dinosaur to become fossilized?
Wet enviroments in low elevation (most likely for the bones to become buried)
Fluvial deposits
River and stream deposits
Lacustrine Deposits
lake deposits
What enviroment is most likely to preserve soft tissue/ hair/ feathers?
Lakes (lacustrine deposits) because of the limited water movement
Aerolin deposits
Wind based deposits
Sedimentary Rock
Rocks that form were mineral and organic particles accumulate to become either cemented or compacted together
Igneous Rock
form when magma and laa cools
Metamorphic Rock
Sedimentary and Igneous Rock that are changed by heat and pressure
Sedimentology
The science of how sedimentary rocks form
Mudstone/shale
Sedimentary rocks that form from mud and silt; found in former lake bottoms
Sandstone
Sedimentary rock that forms from sand; indicate a former beach, river channel, or ocean floor enviroment.
Coal
Special kind of sedimentary rock that is the fossilized and compressed remains of plants; indicates a former swampy enviroment.
Limestone
Sedimentary rock usually formed from the accumulation of shells and exoskeletons of small marine invertebrates; almost always indicates a former shallow marine enviroment
What are the different types of dinosaur fossil preservation?
Permealization: occurs when the empty internal spaces of a bone are filled with minerals
Replacement: occurs when the original bone gradually decays and minerals fill the space that the bones once occupied
Where are dinosaur fossils most commonly found?
Modern enviroments where there is considerable recent erosion (not a lot of vegitaton)- the Badlands
Badlands
arid enviroments where vegitation is sparse, where erosion rates are high and where large expanses of acient sedimentary rocks are exposed
Overburden
The rock and earth that covers a fossil specimen and that must be removed before the full extent of the specimen can be judged (takes large tools to remove)
Bonebeds
Accumulation of the bones of many dinosaurs
What does the amount of abrasion on a dinosaur bone tell us about a dinosaur?
give a relative sense for how far the bones may have been transported by flowing water.
What does the orientation of a dinosaur bone tell us about a dinosaur?
The orientation of the long bones tells us the direction the carcass was flowing after death; if they are aligned in the same direction it can tell us what way the water was flowing.
What are the order of events from the end of a dinosaurs life up to the collection of their bones?
- Death
- Burial
- Fossilization
- Erosion
- Excavation
