Week 3

Question 1

How do we know what ancient climates were like?

Answer 1

Sediment
Ice
Coral
Tree rings

These offer us proxies, which are substitutes for direct measurements. We can only infer information from something such as a tree ring, based on how it might change in response to different climates.

Question 2

Principle of Uniformitarianism

Answer 2

The same processes that were operating millions of years ago are operating today.

Question 3

What can salt tell us about an environment?

Answer 3

Salt is found in coastal areas where you have more evaporation than precipitation.

Question 4

What can coal tell us about an environment?

Answer 4

Coal is created in swampy areas, where living matter, such as plants, falls into stagnant water and doesn’t break down.

Question 5

What can glacial till tell us about an environment?

Answer 5

An area with glacial till must have once been glaciated.

Question 6

How can ice tell us about ancient climates?

Answer 6

Ice traps atmospheric gases in bubbles, these tell us about the concentration of greenhouse gases during that time. BUT ice records only take us so far back, it CAN’T tell us about the time of the dinosaurs because there was NO ICE during the time of the dinosaurs.

Question 7

How can tree rings tell us about ancient climates?

Answer 7

The thickness of tree ring bands can give you an idea of when climates were favourable or not. Thicker bands indicate more favourable weather for growth.

Question 8

How can fossils tell us about ancient climates?

Answer 8

Some plants and animals only live in specific habitats. Like how you wouldn’t find a crocodile in the arctic, it is too cold for them! But they used to live there, so it must have been an appropriate climate for crocodiles at some point in the earth’s history.

Question 9

How can isotopes tell us about ancient climates?

Answer 9

An isotope is an atom with a slightly different mass. Animals will build their shells out of one form or another, and by examining these we can measure the quantities of those isotopes to get an understanding of how the climate might have been during that time.

Question 10

Certain records vary from each other, so we

Answer 10

build records from several sources of data.

Question 11

During the time of the dinosaurs we know that the atmosphere was hotter than it would be today. There was 2-5 times more carbon dioxide in the atmosphere during the time of the dinosaurs due to greenhouse gases, why?

Answer 11

Pangea was breaking up during the time of the dinosaurs, that means there were a lot of divergent boundaries which means we would have seen more volcanism. Volcanoes release greenhouse gases in the atmosphere and keep it warm.

Also the dinos were v gassy and thus produced a lot of methane (greenhouse gas), that vegan diet will do that to you.

Question 12

A bi product of warm temperature is a rise in

Answer 12

sea levels. We know this because we get deposition on continental shelves that were deposited during the time of the dinosaurs.

Question 13

What causes sea level rise?

Answer 13

Tectonic Activity

Climate Factors

Question 14

How does tectonic activity change the sea level?

Answer 14

A larger ocean basin will make for a lower sea level whereas a smaller ocean basin will make for a higher sea level. A change of basin size can happen by

• changing the size of mid ocean ridges
• colliding or separating continents
• filling the ocean basin with sediment.

Question 15

Fast rates of spreading, like those that occurred during the time of the dinosaurs would result in

Answer 15

a wider ridge, which would take up more space and result in a higher sea level.

Question 16

Continent/continent collision creates a bigger ocean basin which results in

Answer 16

a drop in sea level. There was an absence of these during the time of the dinosaurs, which suggests a higher sea level for that time.

Question 17

Sea level can rise due to _____ _____ because hotter water takes up ____ space.

Answer 17

Sea level can rise due to thermal expansion because hotter water takes up more space.

Question 18

Sediments displace ocean water by decreasing the volume of the basin, would this be a significant factor for sea level during the time of the dinosaurs?

Answer 18

No because sedimentation rates were low at that time.

Question 19

If all the ice sheets melted today what would happen to the sea level?

Answer 19

It would rise drastically. Ice sheets=lower sea level. So no ice sheets during the time of the dinosaur means higher sea level for that time.

Question 20

Isostacy

Answer 20

• The sea floor sags or rebounds in response to changes in the volume of water added or removed.
• Earth’s crust sinks down under heavy load, pops back up when you remove the weight.
• Earth’s crust is like a mattress.

Question 21

Why cretaceous sea levels were higher than they are today:

Answer 21

• no major ice sheets
• thermal expansion of seawater
• no colliding continents
• smaller deep-sea fan sedimentation
• higher ocean ridge volume

Question 22

Flooding of coastal areas has a ____ effect on climate. Like Vancouver.

Answer 22

Flooding of coastal areas has a moderating effect on climate. Like Vancouver.

Question 23

The Mesozoic Era

Answer 23

Triassic
Jurassic
Cretaceous

The time of the dinosaurs!!!!!!!!!

Question 24

First Dinos

Answer 24

228 MA

Question 25

Last Dinos

Answer 25

65.5 MA

Question 26

We can’t expect to find dinosaur fossils in igneous or metamorphic rocks due to the nature of how they are created. So we must look at

Answer 26

sedimentary rocks!

Question 27

There are two types of sedimentary rock, clastic and chemical. How can we know which are which and how do we know that we can find dino fossils in clastic rock??

Answer 27

Chemical: Sediments crystallize out of water. These are formed in lakes/seas due to evaporation. Limestone and salt. Can’t find dinos here because they don’t live in water!

Clastic: Sediments deposited on land/beaches in rivers, buried and then glued together to make a rock. Sandstone, siltstone, shale. Dinos lived on land so we can find them here!

Question 28

Sediments are created when rocks are exposed to

Answer 28

wind, rain, heat, cold.

Question 29

Weathering

Answer 29

Exposure breaks rocks down into sediment.

Question 30

Erosion

Answer 30

Sediments are transported downhill.

Question 31

Deposition

Answer 31

Sediments reach low lying spot and pool.

Question 32

Basin

Answer 32

Low lying area where sediments pool.

Question 33

Where do sediments accumulate?

Answer 33

Edges of glaciers, beaches, in rivers, and on the sea floor.

Question 34

What can move sediments?

Answer 34

Water, wind, and glaciers.

Question 35

As we move farther away from the source rocks get smaller or bigger?

Answer 35

Smaller, until they are silt or clay.

Question 36

Asymmetrical Rift

Answer 36

Forms in rivers and deserts.

Question 37

Symmetrical Ripple

Answer 37

Forms in areas of oscillating wave action.

Question 38

Pebble Imprications

Answer 38

Form in rivers, water pushes pebbles in one direction.

Question 39

Mudcracks

Answer 39

Form when water dries up and clay minerals contract.