Lecture 14: Introduction to the Quaternary

Question 1

When did the Quaternary period begin? What is anything before this period regarded as?

Answer 1

~2.6mya. Anything before is regarded as deep time

Question 2

What are the two epochs in the Quaternary Period and when do they stretch between?

Answer 2

Pleistocene: 2.6mya-11.5ky
Holocene: 11.5kya-present

Question 3

What is the Quaternary period characterised by?

Answer 3

Glacial/interglacial cycle in which ice sheets stretched over large areas of the earth

Question 4

What were two ice sheets that existed during the glacial periods of the quaternary?

Answer 4

Laurentide & Scandinavian

Question 5

How are we enable to accurately estimate the climate of the past in the Quaternary?

Answer 5

Vostok Ice Cores

Question 6

What are Vostok ice cores and how far do they stretch back to?

Answer 6

Cylindrical cores that contain air bubbles of past atmospheres and therefore the relative balance between the different gases. they stretch back 800,000 years

Question 7

What have the Vostok ice cores demonstrated in the record over the most recent decades?

Answer 7

A sharp and unprecedented increase in the concentrations of greenhouse gases.

Question 8

What do the IPCC estimate the concentrations of methane and carbon dioxide could be in the atmosphere by 2100?

Answer 8

Methane: 3,500 ppm

Carbon Dioxide: 1,200 ppm

Question 9

What are likely to be the causes of the dramatic changes in the methane and carbon dioxide concentrations by 2100?

Answer 9

Deforestation, oil flaring, automobile use, industry pollution, cement production (anthropogenic causes)

Question 10

What are the global average temperatures expected to reach by 2100?

Answer 10

5 to 12 standard deviations above the Holocene temperature mean

Question 11

In light of the changes that humans are causing, what have some claimed we are now entering

Answer 11

A new phase of earth geological history known as the Anthropocene

Question 12

What was the distribution of the continents like during the quaternary and why does it make this period suitable for investigation?

Answer 12

Relatively similar in distribution - means that we can easily compare between then and now

Question 13

What is the geological archive of the quaternary like?

Answer 13

Wealthy

Question 14

What is an important biological and societal development that takes place during the quaternary?

Answer 14

The birth of hominids and modern society

Question 15

Due to the context of the earth in the quaternary, what does it make it suitable for?

Answer 15

Improve predictions of future climate and therefore we can mitigate and adapt to future changes better

Question 16

Who was the debate between over the cause of the changes in the earth system during the quaternary?

Answer 16

Church and science

Question 17

What geological philosophy did the church adopt to explaining the quaternary changes in the earth system?

Answer 17

Catastrophism

Question 18

What geological philosophy did the scientists adopt to explaining the quaternary changes in the earth system?

Answer 18

Uniformitarianism/gradualism

Question 19

What does uniformitarianism consist of?

Answer 19

there are physical, chemical, biological laws that operate today as they did in the past. These are small scale events and processes that have a gradual and prolonged effect on the landscape

Question 20

What pieces of evidence did the scientists and church debate over?

Answer 20

Erratics
Till
Other (e.g. parallel roads)

Question 21

What are erratics?

Answer 21

Rocks that differ in size and type from those in proximity and are therefore outside of their normal environment

Question 22

What is an example of an erratic?

Answer 22

Saunton Sand (Devon): there are some pink granites found which the closest place they could have from was Scotland (similar rocks there) which must have come here through glacial streams or ice movement.

Question 23

What are tills?

Answer 23

unsorted sediments meaning a variety of rock types and sizes are found in one place

Question 24

where are tills normally found?

Answer 24

northern hemisphere

Question 25

What are the ‘parallel roads’?

Answer 25

This is a geomorphological feature in Glen Roy, Scotland in which there was debate between uniformitarianism and catastrophism over their formation

Question 26

What did the church and science claim to be the cause of the Grand Canyon’s formation?

Answer 26

Church: product of giant flood
Science: product of gradual processes that slowly carved it out

Question 27

What did Charles Lyell state?

Answer 27

“the present is the key to the past”

Question 28

What did David Hume state?

Answer 28

“all inferences from experience suppose that the future will resemble the past”

Question 29

What did James Hutton state?

Answer 29

“the past is the key to the future”

Question 30

What happened between 1787 and the 1790s with Bernard Kuhn and James Hutton?

Answer 30

Kuhn proposed that erratics were dumped by glaciers, then in the 90s agreed after visiting the site

Question 31

What happened between 1839-1840 with Charles Darwin and Louis Agassiz?

Answer 31

Darwin proposed the parallel roads of Glen Roy were a product of previously raised beaches that used to be much higher up, whereas Agassiz proposed they were cut out by freeze-thaw processes of an ice-dammed loch created by a glacier during the Younger Dryas period?

Question 32

What did Louis Agassiz lecture on and where?

Answer 32

Ice Ages at the Swiss Society of Natural Sciences

Question 33

What was Agassiz’s theory for how the earth’s temperature had changed over time? how did it differ from the most common theories at the time?

Answer 33

Instead of the common belief that the earth had continuously cooled from a molten state, he proposed that it had undergone a more disruptive process where by there were glacial and interglacial cycles.

Question 34

What did Louis Agassiz not have to back up his theory of glacial and interglacial cycles?

Answer 34

A mechanism to explain the climatic changes required to cause ice sheet formation

Question 35

What did Joseph Ademhar introduce in 1842?

Answer 35

Orbital eccentricity idea - the earth’s orbit of the sun changes shape which results in periods when the earth is closer and further away from the sun

Question 36

What did James Croll do in 1864?

Answer 36

combined the ideas of Agassiz for the changes in temperature of earth with the theory of Adhemar to propose that the glacial/interglacial periods could be a result of changes in earth’s orbit.

Question 37

Who developed the theory of James Croll the next century?

Answer 37

Milankovic (Milankovitch)

Question 38

What were Milankovic’s ideas?

Answer 38

Other changes in the earth’s orbit took place not just eccentricity but also obliquity and precession. These would then affect the seasonality of changes in climate

Question 39

What did Milankovic do?

Answer 39

He calculated mathematically the details of changes and how this would affect insolation.

Question 40

What latitude did Milankovic predict the biggest changes in climate took place?

Answer 40

65 degrees latitude North