Dinosaur Extinction Flashcards
K/T boundary
K/T: Cretaceous /Tertiary
Tertiary is outdated term
K/Pg boundary
K/Pg Cretaceous / Paleogene
End of cretaceous / end of dinosaurs
Age of dinosaurs - k/Pg Boundary -> age of mammals
K/Pg boundary and K/T boundary
They are the same thing
Rock of K/Pg ( between age of dinosaurs and age of mammals)
Dark
A lot of things burnt?
Softer rock than other rock layers
Spike in Iridium
Found usually from space or deep in earth
Not a lot found normally on earth’s surface
During K/Pg boundary, found A LOT of iridium
Found not only in Italy but around the world
Controversy about where it’s from but most like it’s ET (extraterrestrial)
Was there a gradual decline of dinosaur diversity before the K/T boundary?
More genera in Cam than Maa
But it depends on rock availability
Errors with rock availability and measuring decline of dinosaur diversity
But it depends on rock availability:
Bias of sampling
Suggests no decline in diversity
Statistical errors b/c of little sample size
No consistency in results
Statistically did NOT decrease gradually (dinosaurs were doing fine before the extinction)
What are the Deccan Traps?
LARGE Body of lava found in India
Huge chunk of lava covering large area
Deccan Traps and Magma
To cover a size that large, you need a lot of magma
Mantle
Molten rocks become magma
Magma seeps through crust to make volcanoes
Because there aren’t enough cracks, the magma keeps building up
The older the magma, the smoother it is
Therefore, when it comes out, it doesn’t stop flowing -> covers a much larger area
Erruptions of the Deccan Traps and K/Pg boundary
1st eruption before K/Pg boundary
Last eruption after K/Pg boundary
Deccan traps on and off during that time period
Deccan traps most likely resting before impact
What is the Chicxulub Crater?
Crater (Mexico?)
Half on sea, half on land
Scientists looked for crater after iridium spike
Gravity anomaly in the Chicxulub Crater?
Gravity is actually not constant
We can calculate subtleties in gravity
Found gravity anomaly in crater
Majority of crater sill there
Asteroid impact and its leftovers
Asteroid (which created the crater) impact was so strong, it melted everything around it
Estimates of asteroid diameter = 10 km
Left behind dark layer - carbon leftover
Asteroid impact at an angle?
The asteroid hit at an angle
So the molten stuff went more in one direction than in another
Immediate Aftermath and resulting effects of the asteroid impact?
Ignites fires Melted the limestone under the surface Got to the rocks easily Released a MASSIVE tidal wave Water couldn’t stop the fires because it went in the different area
Deccan Traps and the asteroid?
2 different things happened in India and mexico @ the same time
Was it an instantaneous kill?
Wasn’t an instant thing
Probably tooks years, centuries, etc.
Long time compared to us but a short time period in terms of everything else
Mass extinction
Mass extinction: 75% of all species died
All non bird dinosaurs died
Difficult to kill a lot all at once
What most likely happened during the Mass extinction - from the deccan traps and the asteroid?
Probably ignited fires all over world
Probably why we see black @ K/Pg Boundary in rock
After effects of this beginning of the mass extinction?
Acid rain
Nuclear winter
Greenhouse effect
Acid rain
When the heat melted the limestone, it got absorbed into the air leading to acid rain
Weeks of acid rain
Nuclear winter
Happened first few weeks
The soot of burning gets into air -> blocks the sun
Shields the sun
Plants cannot survive long w/o sun
If plants die, dinosaurs don’t have anything to die -> they die too
Weeks without sun, temperature drops
Greenhouse effect
Once dust settles, left in air was greenhouse gasses
Greenhouse effect
After winter -> much warmer than average temperatures
Deccan Traps during impact
Volcanoes release CO2 into air -> reduce sunlight -> helped asteroid cover even more
Most likely happened before asteroid
Deccan traps most likely resting before impact
