Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

GEO1211: Earth System Sciece: History of Our Planet > Quaternary: Lectures 20-26 > Flashcards

Quaternary: Lectures 20-26 Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® U.S. History flashcards European History 101 flashcards AP® European History flashcards AP® World History flashcards World History 102 flashcards U.S. History 102 flashcards World History 101 flashcards U.S. History 101 flashcards
1
Q

Define rapid/abrupt climate change. What is the importance of this?

A

“When climate system is forced to transition to a new climate state at a rate more rapid than rate of change of external forcing”

Events (excluding the 100k yr period glacial-interglacials) in the Holocene on sub-Milankovitch timescales e.g. 4.2 kyr, stadials, interstadials

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe the Last Glacial-Interglacial Transition. Outline the key events leading to the Holocene.

A

LGIT - sequence of rapid events leading into the Holocene
- ‘Type site’ Lake Windermere in UK providing cores showing sharp transitions (light-to-dark; soil-to-marine)

Devensian (last glacial) –> Bolling-Allerod (interstadial) –> Younger-Dryas (stadial) –> Holocene

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What evidence of the LGIT has there been?

A

Cores (Cumbria):

  • Lake sediments; temp proxies
  • Multi-proxy approach

Pollen:

  • Woodland species indicated warmth e.g. birch
  • Grassland indicate transition periods
  • Tundra indicates cold e.g. sedge
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the Younger Dryas?

A
  • Dramatic return to LGM temps
  • The most pronounced stadial of LGIT lasting 1100 yrs
  • Temp shifts in just 40 years
  • Reduction of >15C in Greenland, 5C in Britain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Global evidence of the Younger Dryas?

A

Tropics:

  • Cariaco basin, Venezuela; varves (annual bands), anoxic conditions, sensitive to ITCZ changes = N Atlantic changes affecting tropics
  • Dongge/Hulu speleothems suggest weakening summer monsoon
  • Lake Huguan Marr China; strengthening winter monsoon

= teleconnections

ITCZ southerly migration indicated by weaker summer monsoon and stronger winter monsoon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Driver of the Younger-Dryas? What has been linked to this event?

A
  • N. American pro-glacial Lake Agassiz collapses = freshwater influx (AMOC disruption)
  • Different events at tropics; SH as a driver itself due to previous meltwater pulse 14.7ka and B-A interstadial
  • Bi-polar seesaw; mechanism debated
  • Rejected/controversial suggestion of impact event

Links to…

  • Sudden disappearance of Clovis culture in N America
  • Megafaunal extinction
  • Natural vs. anthro?
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the 8.2 kyr event? What is the significance of this?

A

Smaller, post-YD event within Holocene, cold snap

  • Temp decrease by 4-8C in 150 years
  • 14% CH4 reduction

Significance?

  • Holocene relatively stable compared to LGIT
  • But considerable variability
  • Internal forcings to investigate
  • Further events e.g. 4.2 (on societal timescales)
  • Helps predict future of GL ice sheet
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Why is it important to study the Holocene, what is it?

A

The present interglacial:

  • Period of relative stability
  • We’re in it
  • Climatic events
  • Anthropogenic change in past context
  • Dawn of modern civilization (Neolithic revolution)
  • Anthropocene?
  • Range of potential forcing mechansisms
  • Wealth of natural archives
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the characteristics of the Holocene? Who first noticed its instability?

A

Blytt-Sernander; patterns of peat decomposition
Von Post & Godwin; pollen changes

Divided into 3 main periods:

  1. Rapid warming (early); Boreal trees
  2. Thermal maximum (mid); Atlantic, maritime environment
  3. Cooling (late); sub-Boreal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why did we enter this period of relative warmth (early Holocene) and what evidence do we have?

A

LGIT = increased northern latitude summer insolation
Last set of Devensian ice sheets melting

Temp reconstruction:

  • NW, CW Europe regional variation with latitude
  • Greater seasonality in N
  • Short-term variability

Main changes identified?

  1. Declining northern mid-latitude summer temps (GL ice core)
  2. Declining Asian summer monsoon, reduced continental heating (Dongge Caves)
  3. Glacial re-advance in NH mostly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How has cyclicity in the Holocene been described/explained?

A

‘Bond’ events are the ice-rafted debris events in the Holocene (D-O, and Heinrich in Pleistocene)

  • 1470 (+-500yrs) periods associated with cooling
  • Linked to LIA, 8.2, YD, 4.2, 2.8 climate events
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the 4.2 kyr event? What evidence is there?

A

Sudden dry period, a centennial scale drought (300-400 yrs)

  • Associated with societal disruption/collapse of ancient civilizations
  • With Bond IRD event 3

Global evidence:

  • 117 records across 7 continents = abrupt change
  • Significant teleconnections (monsoonal regions)
  • Consistent drying in mid-latitudes, wetting in NH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the potential drivers of climate changes in the Holocene, such as the 4.2 kyr event?

A

4.2 = solar activity vs. glacial melt water vs. volcanism vs. imaginary vs. artefact

Forcing?
Orbital
Volcanic
Solar
GHGs (natural vs. anthropogenic)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What can be said about the climate in the last 1000 years? What evidence of change is there?

A

Temp now unlike any point in last 1000 years
With higher ppmv (>400), never seen in last 20,000 or even 800,000 yrs
2050 ppmv predictions will take us to unseen levels for last 10 Myrs

Evidence for climate change events over last 1000 years:
- Medieval Warm Period (vikings, scot wine) and Little Ice Age (frost fayers)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What initially dominated glacial-interglacial cycles? How has this changed?

A

Initially by obliquity (41 ka tilt cycle)

Last 1 Myrs by eccentricity (100 ka shape cycle)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is MIS 5e?

A

The Last Interglacial; Ipswichian

130-115 ka

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What evidence is there for MIS 5e?

A

Landforms:
River terraces
Raised beaches
Caves

e.g. Bobbits hole (UK ‘type site’, 3.5m organic-rich mud, banded terraces) or Trafalgar Square (terrace deposits, evidence of Hippos/Hyenas)

Flora, fauna and humans:

  • Flora from pollen record; warmth (lime, elm), cold (pine, grasses)
  • Fauna; hippos, bison, lions, Elk, Auroch, water vole
  • Hominids; no evidence of humans in British Isles within MIS5e (not until 900 ka)??
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How has MIS 5e evidence varied between the Arctic and tropics?

A

Arctic - deposits, trees, (120ka GL) cores, sea level:

  • Warm-indicator fossil sea shells
  • Ice-free
  • Sea-ice 800km further north
  • Sea level 8m higher
  • Trees 80km north of current extent in N America

Tropics - foraminifera, Mg, warmer:

  • More Mg suggests warmth
  • 1-2C warmer
  • Corals 500km beyond current range by W Australia

Average 1.5C warmer than today - analogue for future IPCC 2C scenario?

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Is the Ipswichian a good analogue?

A

Not really because it was wetter, warmer, had higher sea-levels and smaller ice sheets
Also, earth was closer to sun, the perihelion was in the NH Summer (but is in NH Winter today)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is a better analogue for our current interglacial and why?

A

MIS 11
Similar orbital forcing to today experienced 400 ka
- A prolonged warm period 31,000 years long BUT LESS EVIDENCE FOR IT BCOS OLDER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

How did the idea of evolution and the search for evidence progress since mid-1800s?

A

1856 - Remains of neanderthal in Germany??
1859 - Darwin natural selection
1871 - Ascent of Man, selection in relation to sex
1891 - Most significant finding of Homo erectus in Java
1920s - Hominins in Africa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Outline the scientific classification system from animals to us.

A 
Kingdom
Phylum
Class
Order
Family
Genus
Species
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How has the Hominidae family been further classified to get to us?

A 
Family
Subfamily
Tribe
Subtribe
Genus: homo
Species: sapiens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the difference between ‘Hominid’ and ‘Hominin’?

A 
Hominid = 'Great Apes', currently 8 living species
Hominin = all members of HOMO (human) genus and ancestors of Hominini tribe
25
Q

When were the first hominins estimated to exist? What species was the first of the holocene?

A

2-3 Ma

Homo habilis, first of the HOMO genus, brain 50% of homo sapiens

26
Q

What was the first homo species to go outside of Africa?

A

Homo erectus; brain 60-70% size of ours, 2 myrs survival, co-existed with our early ancestors several hundred thousand yrs ago

27
Q

Outline the development of our ancestors’ distribution.

A 
7-4 Ma - first in Chad (East African Rift Valley)
2.8 Ma - Lucy etc. in S/E Africa
1.8 Ma - first homo genus
1.7 Ma - homo erectus out of Africa
1.4 Ma - into mainland Asia, Indonesia
800 Ka - to N Africa, China, E. Europe?
28
Q

Give the 3 species of homo genus linked to initial dispersal.

A

H. erectus - Asia
H. neanderthalensis - W. Asia and Europe
H. sapiens - N/E/S Africa

29
Q

Describe Homo neanderthalensis and Homo sapiens.

A

H. Neanderthalensis = stocky, cold-adapted, advanced tools, social structure, rudimentary language, larger brains, dominated Europe

H. sapiens = cultural ability to use complex tools, divie labour, practical and social innovation (first out of Africa 125 Ka)

30
Q

Desribe the dispersal of Homo sapiens (2 phases) and the evidence of co-existence with neanderthals.

A
  1. 120 Ka; middle-east, s. Asia and Australia
  2. 60 Ka; Europe, N. Asia, Indonesia
  • Conflict (aggression evidence)
  • Competition (sapiens divided labour, less isolated)
  • Copulation (sex, inter-breeding; modern non-Africans possess 1-3% Neanderthal DNA!)
31
Q

Where/when was the ‘centre for human evolution’ and what have changs been linked to. How can the climate and environment be further linked to hominin evolution?

A

East Africa, 10-2 Ma
- Tectonic transformation = rifting resulted in more lakes, coincident with speciation, dispersal, and encephalisation (1.8 Ma homo erectus)

Climate change and 1st sapiens our of Africa:

  • Freshwater fluxes, ice sheet surges
  • ITCZ southerly migration
  • Cooler, drier
  • Changes in African vegetation cover
  • W. Africa changes forcing sapiens out of Africa

Later:

  • Last glacial forced neanderthals and sapiens out of Europe
  • Neanderthals poorly adapted for warmer climate?
32
Q

Describe recent evidence of hominin species (2004, 2010)

A

2004; 9 individuals, 1 complete skull = Homo floresiensis, THE HOBBIT, 12 ka (or 50 ka)

2010; Denisovan hominin, 41 ka, unclassified

33
Q

What is the Palaeolithic? How is it demarcated?

A

The ‘OLD’ Stone Age

  1. Lower - pre-H sapiens in UK
  2. Middle - H sapiens etc.
  3. Upper - 30k-10.5ka, humans absent in British Isles during LGM
34
Q

Outline the discoveries of the first Britons in order.

A
  1. Boxgrove, W. Sussex (1982-1996)
    - Axes, flints, megafauna
    - 500,000 yrs ago in MIS13
    - Cut marks on bones
    - Oldest hominin remains in British Isles
  2. Pakefield, Suffolk (2005)
    - Percussion flakes, aces
    - 700,000 yrs ago in MIS17
    - Mediterranean species and specific water voles
  3. Happisburgh footprints (2013)
    - 900,000 yrs ago
    - Oldest outside of Africa
    - Associated with Homo antecessor
35
Q

What other evidence is there of human activity? What are the implications?

A

Swanscombe woman (homo erectus; 400ka)

Kent’s Cavern ‘Neanderthal’ (42ka; homo sapiens)

Figures and flute: Venus (40ka), flute (41 ka), Lion Man (32ka)

36
Q

Outline significant discoveries of the upper Palaeolithic.

A

Recolonization 14,700 yrs ago after LGM
Cannibalism
‘Cheddar Man’ in Goughs Cave (1st anatomically modern skeleton)
Settlements 12k-10ka

37
Q

What is the Mesolithic? What is it characterised by?

A

‘MIDDLE Stone Age’
10,500-6,000 yrs ago
Dramatic technological advancement
Microlithic flaked tools and blades, more advanced; nets, boats and paddles
Changes in subsitence farming patterns, seasonal specialisation (indicated by isotopic studies on teeth)

38
Q

What is the Neolithic?

A

‘NEW Stone Age’
6,000 yrs ago
Neolithic Revolution (Dawn of Anthropocene?!)
- Nomadic to agriculture/permanence
- Domestication of plants
- Animal husbandry (animal training/breeding)
- Population increase

39
Q

What were the first animals to be domesticated and where? What is the most significant thing about dogos?

A

Wolves ~36,000 years ago in Europe (undisputed mandible 14,700 yrs ago) - ‘convergent evolution’

Middle East 11ka e.g.
Aurochs –> cows
Wild boar –> pigs
Moufflon –> sheep

S America - llamas, alpacas (6ka)

Asia (S, E and C) - horse, camel, chicken

N America - turkey

40
Q

How did agricultural practice develop?

A

Independently in multiple locations by technological advancement e.g. irrigation, deforestation, food storage

41
Q

Give 3 examples of food domestication.

A
  1. Near East/Levant - lentils, chickpeas, wheat 10ka
  2. Far East - China, then India; Millet, Rice
  3. The Americas - Mesoamerica; squash, beans, maize and S/N America; chillies, cotton, potatoes
42
Q

What are the 4 hypotheses for dawn of agriculture? Why did society shift to permanent settlements?

A
  1. Cultural progress
  2. Environmental change
  3. Population pressure
  4. Accident and opportunity
43
Q

What are the 6 main areas of independent ‘civilization’

A
  1. Mesopotamia, Syria, Iraq (Akkadians)
  2. Mesoamerica (Olemec)
  3. Indus Valley, Pakistan (Harrappans)
  4. Ancient Egyptians
  5. Ancient China
  6. South America
44
Q

What is the ‘early anthropocene hypothesis’?

A

That the Anthropocene began as early as 8,000 years ago; major alterations to the planet began here:

  • Natural CO2 and CH4 trend decline, current trend anomalously high
  • Should be netering a glacial, based on length of previous interglacials (MIS5e)
45
Q

Why is the Early Anthropocene Hypothesis disputed? What has it implied?

A
  • Holocene is a ‘super-interglacial’ like MIS11 on a longer 400ka eccentricity cycle
  • Human population 8ka was too small to make a substantial footprint

But still…

  • Evidence for substantial affect earlier than thought
  • Peatland investigations = trace metal elemts for different stages of metal smelting up to 4000 years ago
46
Q

What evidence do we have of activity in the Neolithic within Britain and Ireland? (Orkney)

A
  • Monuments e.g. stone henge
  • Deforestation and agriculture from pollen records

Orkney:
- Skara Brae, Ring of Brodgar, Maeshowe

47
Q

Describe agricultural change within Neolithic Britain (and expansion from S. Europe)

A

Deciduous trees 3.5 ka to a rise in pasture/meadow
Expansion of agriculture from Turkey and Greece 8kya up to the British Isles 5kya
Modern DNA analysis = spread of agriculture

48
Q

What did the Bronze and Iron Ages enable?

A

Bronze Age (~4ka, temporal/spatial variance) - first major settlements; greater range of environmnts could be farmed

Iron Age (2.7ka); impoved tools, widespread deforestation to south

1086AS Doomsday - 15% original forests remained 1000 yrs ago

49
Q

What evidence in the landscape is there of very early British land management?

A

Ancient Field Systems (Bronze Age)

  • Ceide Fields, County Mayo
  • Dartmoor Reaves, Devon (3000 yrs ago)
50
Q

What is palaeoecology and what are the implications of it? What example can we use?

A

Reconstruction of past environments using peat cores, pollen records etc.

Dartmoor National Park

  • Not actually pristine wilderness
  • 4,500 yrs ago; largerly forested
  • Charcoal recorded
  • Tree reduction 2ka

Can see effects over history, from pre-history, tin mining, grazing and peat cutting
- Need to set conservation targets e.g. do we rewild the landscape?

51
Q

What key (climatic) events can be discussed with regards to the last 1000 years?

A

Medieval warming period (950-1250 AD)

Little Ice Age (1650-1900)

The Great Acceleration from 1950s (Steffen et al., 2011 - plethora of variables all increased since 1950)

52
Q

What can tree rings indicate? How long is the record, how was this possible?

A

Dendroclimatology (palaeoclimatic data) and dendrochronology (chronological info)

  • Annual bands = high resolution, seasonal reconstructions
  • Indicates climatic conditions based on the “stress” placed on the tree
  • Ring thickness: temperature, precipitation, moisture availabiltiy, drought
  • Scars: fires, pests

~7000 year record:

  • Live, dead, fossilised trees; buildings/ships
  • Patterns can be matched between trees
53
Q

Why are tree rings crucial tools in accurate radiocarbon dating?

A

Help with radiocarbon calibration to find true calendar age

Tree rings record exactly how much atmospheric 14C has varied over time

If same proportion of radiocarbon aas that of a given tree ring, it is safe to conclude they are of the same age

54
Q

What is radiocarbon decay and dating, and half-life? What are the issues with it?

A

With organic samples…
The age (up to c. 50,000 years) can be calculated based on the amount of radiocarbon left in the sample because radiocarbon accumulation stops upon death
- Radiocarbon is an unstable isotope of carbon (14C) that decays at a known rate
- Decay = split into parent and daughter nuclides
- Half-life = time taken for quantity of parent nuclide to reduce by 50%
- Complicating factors that affect amount of radiocarbon in atmosphere unaccounted for e.g. solar activity so needs calibration = lots of uncertainty

55
Q

Outline the internal (sub-Milankovitch) forcing mechanisms of climate in the last 1000 years.

A

Solar irradiance and volcanism

Anthropogenic - albedo alteration, aerosols, land-use change, GHGs

56
Q

Define the Anthropocene.

A

Where humans are no longer just a temporary disturbance
Have shaped and influenced plethora of Earth System processes
New ‘anthroposphere’
Geomorphic agents (30 tonnes earth moved per person?)

57
Q

Describe the Anthropocene in terms of biodiversity, biogeography and climate.

A

Biodiversity - 6th mass extinction, land-use change, habitat loss
Biogeography - invasive species, homogenisation
Climate - GHGs, temp increase, ice reduction, sea-level rise, permafrost melt, habitat loss by climatic changes

58
Q

How has the Industrial Revolution been proposed as the true ‘Dawn on the Anthropocene’? How has the IPCC used this?

A

Crutzen (2002) since late 18th century

  • Increasing GHGs in polar ice cores
  • New steam engines & fossil fuel burning (Newcomen, 1712; Watts, 1784)
  • Flow-on effects - more efficient land-clearance methods (pop growth)
  • IPCC’s ‘pre-industrial’ point is 1750
59
Q

Why do we need a marker of the Anthropocene? What/when is the most recent marker suggested?

A
  • Consistency in term usage
  • Correlation to human behaviour
  • Natural baseline to work towards

1945 Nuclear bom testing = Oct-Dec 1965 bomb peak (increased 14C recorded by Sitka Spruce tree rings)

GEO1211: Earth System Sciece: History of Our Planet (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions