Lesson 2 Flashcards
taphonomy=
studying how bones are situated in the sediments
tells us what happens between time of death of the animal and the time it was buried and dug up
What are 3 things we can learn about the dino from taphonomy?
- enviro it was living in
- cause of death
- what the animal was doing up to the time it died (if we’re lucky)
why is dinosaur provincial park a good place to look for dino bones?
a. the region was once covered by massive glaciers.
b. the dry climate limits plant growth.
c. the rock exposures date back to 100,000yrs
d. during the age of dinos, the region was a forested mtn range
a and b
ice acted as a bulldozer: removed younger sediments, revealed the older sediments with dino fossils (cretaceous). wind and rain + glacial melt continued erosion
t/f
forests and mountain areas seldom preserve fossils
true
what 4 factors should you consider when looking for dino bones in a certain location?
- need exposures (if the rocks are covered by concrete cities or forest/soil, it’s hard to access anything)
- the rocks have to represent the correct age (cretaceous period)
- the correct enviro represented (terrestrial, not marine)
- it helps to know you found dino bones in that location before
is dinosaur provincial park a good place for fossils to form today?
no!
very dry today, no mud to preserve bones
why was dinosaur provincial park a good place for fossils to form in the past?
there were rivers carrying sand/ mud that buried the animals and preserved them well
What would the terrain and climate have been like when the dinosaurs
were alive?
- wet
- dry
- hilly
- flat
- rivers and wetlands
- plains and bluffs
chose 3
wet
flat
rivers and wetlands
what is the main shared characteristic of all sedimentary rocks?
they’re breakdown products of other rocks
& then redeposited by water/ wind in layers
explain likelihood of finding fossils in sedimentary vs igneous vs metamorphic rocks
sedimentary= good places for animals to get buried and therefore fossilized
igneous= represent ancient, molten magma, which is not a good place for things to be fossilized
metamorphic= sedimentary or igneous rocks that have been changed by heat/ pressure deep underground. Not going to find fossils there!
are dino fossils ever found in ancient marine sediments?
yes!
although all dinos were terrestrial, some lived near coasts. Some were washed out to sea, then sunk and were preserved in ancient seafloor sediments
river deposits are typically _____ (__stone)
lake deposits are usually made of ___ or ___ (___stone or ___)
swampy areas with lots of vegetation can make a special kind of sedimentary rock called ____
lagoons/ shallow seas deposit ____
sand (sandstone)
mud (mudstone or shale)
coal (fossilized compressed remains of plants)
limestones (chalky sediments composed on plankton exoskeletons- typical of marine envios)
Why may we not find a complete articulated skeleton?
a. The skeleton is in a flowing river.
b. The carcass is scavenged.
c. The dinosaur dies in a forest.
d. the bones are scattered randomly by other animals
a. The skeleton is in a flowing river (the bones will become worn down and break apart)
b. The carcass is scavenged (predators are good at breaking up large carcasses)
d. the bones are scattered randomly by other animals
Preservational Styles=
ways fossils can form
What are the two main categories of Preservational Styles?
- permineralization: internal spaces of tissues and bones are filled with dissolved minerals carried by water
- replacement: original material is replaced by minerals (no original material is left). This is a cast/ impression
plastic deformation=
weight of sediments above the bones + the pressure of rocks below/ to sides cause the fossil to be a bit deformed.
Occurs after the bones have been fossilized
Of the following, what is the correct order of events that occurs
between the death and excavation of a dinosaur?
fossilization
burial
death
excavation
erosion
Death, burial, fossilization, erosion,
excavation
why are there so many dino teeth found in dino prov park?
b/c dinos shed their teeth throughout their life! (like sharks)
so one animal could produce 1000s of teeth in its life
and they fossilize well
bonebeds=
massive accumulations of bones of many individual animals (usually at a river channel)
- the bones found here normally represent long-term accumulations of bones that have washed downstream & dropped where the water slows
how would preservation be different in sandstone vs mudstone?
sandstone= coaser grain, so faster moving waters. dino would be buried very rapidly by sand, so preservation is different than what we find in mudstone, where the water was slow
type specimen=
the specimen that bears the name for a new species. Very important!
how long does it typically take to collect a dino from soft sandstone?
3 weeks ish in dino prov park
airscribe=
a special tool, like a tiny jackhammer used when a rock is too hard to remove from a fossil using picks alone
____ different bones from endomtosaurus and albertosaurus have been collected from the danek bed
1000 ish
The danek bed mostly contains:
Where is the danek bed located?
remains of the hadrosaurid edmontosaurus
edmonton
to estimate how many animals may be in a bonebed, what technique is used?
use a unique bone, like a left femur (each animal only has 1). So if you find 15 of these, then there were a minimum of 15 different animals in that bonebed
do we have evidence that albertosaurus scavenged on edmontosaurus?
yes!
albertosaurus teeth found mixed in with edmontosaurus fossils: they lost their teeth while feeding (they shed their “baby teeth”)
each quarry map represents ___ of the bonebed
1m squared
If all the bones in a quarry map are oriented in different directions, that suggests they were deposited in a ___-moving system
slow (water)
