How has the Earth changed?

Question 1

What were the 8 previous continents?

Answer 1

Vaalbara
Ur
Kenorland
Columbia
Rodinia
Pannotia
Pangaea

Question 2

What was Vaalbara?

Answer 2

3.5 Billion years ago.
A single small continent

Question 3

What was Ur?

Answer 3

3 Billion years ago.
Half the size of Australia

Question 4

What was Kenorland?

Answer 4

2.7-2.6 Billion years ago.
Supercontinent

Question 5

What was Columbia?

Answer 5

1.8 Billion years ago.
1/3rd of present land area

Question 6

What was Rodinia?

Answer 6

1.0-0.6 Billion years ago.
Supercontinent

Question 7

What was Pannotia?

Answer 7

0.65-0.56 Billion years ago.
Short lived supercontinent

Question 8

What was Pangaea?

Answer 8

0.3-0.17 Billion years ago.
Last major supercontinent

Question 9

What did Pangaea break into?

Answer 9

Gondwana and Laurasia
(Iapetus ocean between)

Question 10

When did Pangaea first break up?

Answer 10

Around 200 million years ago (Triassic)

Question 11

What did Gondwanaland become?

Answer 11

Antarctica, South America, Africa, Madagascar, Australia and India

Question 12

When did Gondwanaland break up?

Answer 12

In the Cretaceous

Question 13

When did Gondwanaland hit Laurasia?

Answer 13

In the Carboniferous.

Question 14

What is stage 1 of the Wilson cycle?

Answer 14

Breaking of stable continent from thinning + fracturing.
Likely due to a mantle plume.
New divergent boundary
E.g. EARV

Question 15

What is stage 2 of the Wilson cycle? (after new divergence)

Answer 15

Ocean basin generated ridge push.
E.g. Red Sea

Question 16

What is stage 3 of the Wilson cycle? (after ridge push starts)

Answer 16

Ocean basins widens.
Ocean is opening while subducted occurs further down.
Growing ocean.
E.g. Atlantic Ocean

Question 17

What is stage 4 of the Wilson cycle? (after growing ocean)

Answer 17

Closing stage. Subduction.
Convergent boundary.
E.g. Pacific ocean

Question 18

What is stage 5 of the Wilson cycle? (after subduction)

Answer 18

Most ocean subducted.
Continents close to colliding.
Convergence is still happening
e.g. Mediterranean

Question 19

What is stage 6 of the Wilson cycle? (after most ocean subducted)?

Answer 19

Collision.
Ophiolite suite in mountain range.
No more tectonism

Question 20

When did the Great Oxygenation Event occur?

Answer 20

Around 2.8 Billion years ago

Question 21

What caused the Great Oxidation Event? (drivers)

Answer 21

Cyanobacteria.
These were photosynthetics. Started releasing oxygen for the first time

Question 22

Why was the introduction of oxygen such a big deal?

Answer 22

It was new.
It was poisonous to the species around (micro-organisms).

Question 23

What did earliest photosynthetics absorb?

Answer 23

CO2 and CH4
(Carbon dioxide & Methane)

Question 24

What did the early absorption of CO2 & CH4 do to the climate?

Answer 24

Less greenhouse gases led to colder climates.
Led to a global ice age

Question 25

What was the name of the ice age caused by the Great Oxidation Event?

Answer 25

Huronian Glaciation

Question 26

Why were oceans red in during the Great Oxidation Event?

Answer 26

Oxygen reacted with Fe (iron) in the oceans - which covered most of the land. This formed the BIFs

Question 27

What is the order of the Geological column?

Answer 27

Cambrian Ordovician Silurian Devonian Carboniferous Permian Triassic Jurassic Cretaceous Paleogene Neogene Quarternary

Question 28

What was the Primitive atmosphere like?

Answer 28

Probably H and He, but these likely escaped (light gases). Gases from volcanoes. Water vapour, Nitrogen, Ammonia, Methane and Carbon dioxide

Question 29

How did oceans form from the Primitive atmospheres?

Answer 29

H2O vapour condensed to form the oceans. Leaving CO2 as the dominant gas

Question 30

When were oceans first formed?

Answer 30

Around 4 Billion years ago

Question 31

What are the current CO2 levels in the atmosphere?

Answer 31

Around 430ppm

Question 32

How have CO2 levels changed over 600 million years, and how do current levels compare?

Answer 32

Overall, the current CO2 levels seem high but are actually low compared to what they have been.

Question 33

When were the highest CO2 levels measured? (atmosphere)

Answer 33

Cambrian. Dropped after this from photosynthesis formation. jumped from 4500-7000ppm for a short period of time.

Question 34

Once the iron was oxidised in oceans, what did the oxygen do?

Answer 34

Move to the atmosphere

Question 35

What did the Great Oxidation allow for?

Answer 35

The Cambrian explosion

Question 36

What is 'greenhouse Earth'?

Answer 36

Warm periods on Earth. Lack of ice coverage + overall increase in global temps.

Question 37

What causes greenhouse Earth?

Answer 37

Can be an increase in solar radiation or a change in atmosphere gases (concentration). Can be volcanic events

Question 38

What is meant by Eustacy?

Answer 38

Changes in the volume of the sea resulting in changing sea levels. E.g. due to temps (expansion) or changes in ocean floor (pillow lavas)

Question 39

How do rocks evidence climate change?

Answer 39

Different rocks more prevalent in different climates. Some are only present in certain climates. Weathering can vary with climate

Question 40

What does coal tell us about the environment of deposition?

Answer 40

Lots formed in the carboniferous due to warm and wet. Productive ecosystems (peat). Rapid plant growth. High rainfall + temps E.g. rainforest

Question 41

What does desert sandstone tell us about the environment of deposition?

Answer 41

Hot, arid, dry. Sad at surface = red (oxidation). Fine, rounded, sorted = high energy. Mostly quartz. Wind dunes, deserts

Question 42

What do evaporites tell us about the environment of deposition?

Answer 42

Quick changes from wet-dry. Low rainfall + high evap. Deserts

Question 43

What do tillites tell us about the environment of deposition?

Answer 43

Glacial deposits - cold. Ancient boulder clay. Commonly high latitudes

Question 44

What does reef limestone tell us about the environment of deposition?

Answer 44

Warm + shallow. Mainly built of colonial corals to restricted latitudes (30N+S)

Question 45

What is paleontology?

Answer 45

The branch concerned with fossilised organisms

Question 46

How does Paleontology evidence climate change?

Answer 46

Different organisms based on different atmospheric conditions, some are specific climates. Based on modern day animals and how they relate

Question 47

What evidence does coral provide for past climates?