Death and Fossilization Flashcards
What is taphonomy?
study of natural processes that involve an organism after it dies (including decay, scavenging, fossil, erosion)
TRUE or FALSE: dinosaur carcasses are found in the same location where they died.
FALSE –> they move via scavengers/predators carrying their carcasses and “bloat-and-float”
What is the bloat-and-float phenomenon?
after death, body swells with putrid gasses –> float –> transported by flowing water
Name some factors that causes disarticulation of a skeleton (aka incomplete dinosaur skeleton).
- partial consumption by carnivores
- rotting can make the body easier to damage
- water currents carry away body parts
- prolonged exposure to sunlight weakens/disintegrates bones
- partially buried skeletons may lose unburied portions
- trampling
- plant roots leach away mineral content of bones
What is plastic deformation?
occurs when pressure causes shape of a buried fossil to change even after the pressure is removed (i.e. does not return to original shape)
How does burial of a dinosaur carcass often occur?
water washes sand or mud over the carcass
Fossilization is more common at:
a) low elevations
b) high elevation
Explain your choice.
a) low elevations
Low elevations promote fossilization because sand and mud carried by water can permanently build up (whereas, sand and mud are eroded at high elevations before they can permanently build up).
What are fluvial deposits?
river and stream deposits
What are lacustrine deposits?
deposits (animals that died) preserved in lakes
Which type of deposits have a better chance of preserving soft tissues like hair or feathers?
a) lacustrine deposits
b) fluvial deposits
c) aeolian deposits
Explain your choice.
a) lacustrine deposits
- little water movement –> less disruption to skeleton
- mud/fine sediment better for preserving feather impressions than sand/large sediment
Even though there were no marine dinosaurs, we sometimes find dinosaurs in ancient _____________ environments, if the dinosaur was washed out to sea during a storm or tsunami. (Fill in the blank.)
coastal
TRUE or FALSE: many dinosaurs can be found in deeper-water environments.
FALSE: this is very rare (mostly found in coastal environments)
Dinosaurs in the deserts of Mongolia could be buried by _______ ________ that collapsed onto the still living animal. (Fill in the blank.)
sand dunes
Why are the dinosaurs of Mongolia often preserved in crouching positions with their necks reaching up towards the air?
when dunes become wet and saturated, during heavy rainstorm, the dunes collapsed onto the dinosaurs
What kind of rock/stone are dinosaurs in Alberta often found in?
sandstone
What is the name of the preservation style where empty spaces of bone are filled with minerals?
Permineralization
What is plastic deformation
It is when the skull becomes distorted by the pressure of weight and rocks all around it
How can we prevent a fossil from beign eroded
It must be kept buried
Where are dinosaur fossils most commonly found
In modern environment where there has been recent erosion
True or false - places of rich vegetation are good for finding fossils
False
What is the name given to areas of sparse vegetation and high erosion rates
Badlands
True or false - Badlands consist of ancient igneous rocks that are exposed
False - ancient sedimentary rocks
What is an accurate characteristic of an ideal dinosaur
A skeleton that is freshly exposed above ground
What is the first step excavation
Overburden
What is overburden removal and what tools can you use
The removal of the covering rock and earth that must be removed before analysis ; shovels, pickaxes and bulldozers can be used
What is an indication of the flow of current that carried the bone bed
Long bones that are aligned in the same direction
True or false - fossil bones are very strong and can support their own weight
False - they are weak and brittle
What is an important step that must be done before transporting the fossil bone to the lab
It must be covered in protective material such as paper towel or aluminum foil
What is the order between Death and Excavation
a)Death, fossilization, Burial, erosion, Excavation
b)Burial, death, fossilization, erosion, excavation
c)Death, burial, fossilization, erosion, excavation
C
What can abrasion of bones tell us
Tells us how far the bones have been transported by flowing water
What are examples of long bones
Femur and humerus
What are the 3 different types of rocks, explain briefly each one
Sedimentary - are compacted rocks that are formed from the accumulation of mineral and organic particles
Igneous - rocks that form from cooling magma and lava
Metamorphic - rocks that form by the changing of sedimentary and igneous rocks from heat and pressure
____ rocks that form from mud and silt are called _____ and ____
sedimentary; mudstone; shale
what does mudstone and shale tell us about the environment
it indicates that it was a former lake bottom environment
what are the sedimentary rocks formed from sand and what do they tell us
sandstone; indicates a former beach or ocean floor environment
what is coal made of and what does it tell us
it is made of compressed remains of plants ; indicates a former swampy environment
what kind of sedimentary rock tells us there was a former marine environment
limestone
what is limestone made of
it is formed from the exoskeletons of small marine invertebrates
