Lecture 2 Flashcards
What was the climate during the age of dinos?
1) Continents kept rearranging throughout the time of dinos
2) climate and environmental conditions were very different and varied through time.
How did super continents at the beginning of the time of the dinosaurs have an impact on climate?
The coasts were wet; the interiors were arid (deserts)
The interiors also experienced stronger seasonal temperature swings
What discovery allowed us to see weather from the fossil record?
the foot prints of minisauripus with raindrop impressions
Why is the regulating effect of being near a water body so strong during the time of pangea?
because it was so big
What three pieces of evidence allowed us to see that during the beginning of the time of the dinosaurs
The coasts were wet; the interiors were arid (deserts)
and
The interiors also experienced stronger seasonal temperature swings
desert sands and salt deposits- find desert sands in dry places and salrt deposits formed in lakes and restricted seaways indicating more evaporation occured and left salt crystals than water entered (shows the interiors were arid)
Coals- coals formed in warm wet coastal swamps near the equator, they form when vegetation falls into water and doesn’t break down and then gets buried compressed and heated forming diff types of coal, see these coals in the coasts.
glacial till- we also find glacial till near the south pole which tells us it was once glaciated
As Pangea began to break up what happened to the continents? How did this effect climate?
The continents became smaller, therefore temp swings and aridity in the interior wasn’t that extreme and climates warmed up
Global average temperature was how many degrees warmer than the present?
4-9 degrees warmer.
At the time of the dinosaurs what was the temperature gradient between the equator and poles?
The equator was hot and the poles were cold but the temperature gradient was not at large as the one we see today
Was there permanent ice at the time of the dinosaurs? Was there snow?
there was snow, but no ice at the poles during most of the time of the dinosaurs
The further back you go in the climate record, the less _____ it becomes?
reliable and complete
A 2015 online poll by
YouGov says what percentage of Americans believe humans
and dinosaurs lived at the same time?
41%
What are the two main causes of climate change?
changes in the amount of solar radiation reaching earth
and,
changes in the amount of greenhouse gases in earth’s atmosphere
What are the changes in the amount of solar radiation reaching earth?
there are changes in the sun’s intensity and changes in the distance of the earth from the sun
What are the four main climate archives that allow us to know what ancient climates looked like?
sediment
ice
coral
tree rings
How do the four main climate archives contribute to our knowledge of the climate record?
they preserve continuous records that are datable, they are proxies for climate change as they respond in specific and predictable ways to climatic and environmental changes
What is the principle of uniformitarianism?
That earth is very old and the processes of it have been unform over time, therefore the study of modern geologic processes is useful to understand past geologic events
How do sedimentary rocks serve as evidence for what the climate was like during the mesozoic?
Different rocks form in different environments, sedimentary rocks form in coastal areas with evaporation, swampy areas with plants and cold areas with ice
How do ice serve as evidence for what the climate was like during the mesozoic?
Ice traps atmospheric gases in bubbles. These tell us the concentration of
greenhouse gasses.
The ice record goes back how many years?
2.7 million years
How do tree rings serve as evidence for what the climate was like during the mesozoic?
Seasonal
changes in growth rates
produce bands. The
thickness of the bands
tells you whether climates
were favorable for growth;
the number of bands can
be counted to figure out
how old the tree was
when it died.
Thick bands indicate rainy seasons, thin bands indicate dry seasons
How do fossils serve as evidence for what the climate was like during the mesozoic?
some plants and animals only live in specific habitats, can see fossils in diff environments and ascertain the habitats there
How do isotopes serve as evidence for what the climate was like during the mesozoic?
Fossils and sediments contain isotopes of elements like carbon and oxygen. Animals will
preferentially build their shells out of the lighter isotope, but the ratio of light to
heavy isotope varies with temperature. We can measure the changes in light/heavy
isotope ratios over geologic time to infer how climate changed over time.
Why should we compare between different archives?
because each archive responds differently to change, has variable resolution and provides good records for diff intervals of time
During the time of dinosaurs was temperature relatively warmer or colder? Did it vary from place to place?
warmer, it varied from place to place which shows there was regional climate differences
