Brainscape's Knowledge GenomeTM

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


See full index

ES2001 > Extreme Climates > Flashcards

Extreme Climates Flashcards

1
Q

What are the five geological indicators?

A

Palaeomagnetism
Presence of liquid water
Cold/Ice
Hot/Dry
Flora/Fauna

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

What does palaeomagnetism show?

A

Mineral alignment is igneous and sedimentary rocks are aligned with Earths magnetic field therefore can determine palaeoaltitudes

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

How do we know of liquid water presence?

A

Ripples, cross bedding, fluvial channels, conglomerates

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

How do we know a palaeoclimate was cold/icy?

A

striations, dropstones, till/diamictite, ice rafted detritus

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

How do we know a palaeoclimate was hot/dry?

A

evaporates (hypersaline)
requires a restricted basin

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

What do flora/fauna tell us about palaeoclimates?

A

known climatic ranges
palm trees, cold blooded animals ie alligators in the artic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What do geochemical indicators show?

A

chemical measurements of sediments/fossils that record temperature through 18O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are foraminifera?

A

single celled zooplankton, calcareous shell
planktonic or benthic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why are foraminifera useful in the reconstruction of past climates?

A

As they grow their shells, they take in oxygen isotopes from seawater which tells us about the climate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the 18O water cycle?

A

16O is preferentially evaporated from seawater
18O is preferentially removed by precipitation
High latitude precipitation becomes very enriched in 16O
Extremely 16O enriched water is locked up in high latitude ice sheets
Global seawater becomes comparatively enriched in 18O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When is 18O in foraminifera shells high and low?

A

increases in glacial periods
decreases in ice melt warm climates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What phases do oxygen isotopes prefer?

A

16O prefers less dense phase
18O prefers more dense phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the biggest Carbon reservoir?

A

sedimentary rocks

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are organic carbon sinks?

A

Photosynthesis
Formation of C org which can be buried in C org-rich sediments

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

What are inorganic carbon sinks?

A

Formation of CaCO3 minerals
Burial on seafloor carbonate ooze, limestone or chalk

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

What are characteristics of snowball earth?

A

Glacial deposits (dropstones, diamictites) at low latitudes
cap carbonates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q
A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a mass extinction?

A

A widespread and relatively rapid decrease in biodiversity
When the rate of extinction > rate of speciation

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

What are the big five mass extinctions?

A

End Ordovician 440Ma
Late Devonian 365Ma
Permian Triassic 252Ma
Triassic Jurassic 201Ma
Cretaceous Paleogene 66Ma

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

What extinctions are related to ice house conditions?

A

End Ordovician
Late Devonian
Triassic Jurassic

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

What was the largest mass extinction?

A

Permian Triassic
96% marine species
70% terrestrial species

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

What LIPs have temporary correlation with mass extinctions?

A

Siberian Traps - PT
Viluy - Late Devonian
Central Atlantic Magmatic Province - TJ
Deccan Traps - KT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How does volcanism affect climate?

A

Release of GHGs (CO2, Cl, SiO2 - block up sunlight)
Ocean acidification
Acid rain
Release of organic carbon from Corg rich sediments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the transitions of icehouse/hothouse during the Cenozoic?

A

hothouse warming conditions Paleocene, Eocene (66-34)
cooling conditions Oligocene and Miocene (34-5)
icehouse in Pleistocene (<2.7)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what were the temperatures during the early Eocene?

A

12-16 degrees warmer than today

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What period is the best for recent geological analogues for anthropogenic climate change?

A

Cenozoic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How do we know that climate has changed over the past 66Ma?

A

Marine Sediment Archives
Core Sample Preparation
Foraminifera

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How do we use marine sediment archives to examine climate change?

A

Topographic highs on the seafloors are drilled above the carbonate compensation depth (CCD)
Cores extend back to the late Cretaceous

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the marine snow line?

A

Carbonate compensation depth CCD
Line above which white calcium carbonate is preserved
CaCO3 rich sediments contaon abundant calcareous microfossils

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Where are marine sediments archives from the Atlantic ocean stored?

A

Bremen core repository

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What happens in core sample preparation?

A

Small calcium carbonate microfossils are separated from the sediment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What are the four foraminifera depth habitats?

A

Mixed layer planktic foraminifera = 0-60m (photosynthetic algae)
Deeper dwelling planktic foraminifera = 100-200
Epifaunal benthic foraminifera = seafloor
infaunal benthic foraminifera = shallow depth below seafloor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How do work out the age of a marine sediment core and identify which part of geological record its from?

A

Generate an age model

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are the types of age models?

A

Biostratigraphy
Magnetostratigraphy
Chemostratigraphy
Orbital Tuning

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

How is biostratigraphy used as an age model?

A

Morozovella subbotine (56-53Ma) vs morozovella velacoensis (60-56Ma) abundance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

How is magnetostratigraphy used as an age model?

A

Changes in earths magnetic field are recorded by orientation of minerals in deep sea sediments
Boundaries between normal and reverse polarity zones can be correlated to the Global Polarity Time Scale

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

How is chemostratigraphy used as an age model?

A

Based on rough biostratigraphic framework
Use thickness of core between dated events to calculate sedimentation rates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

How is orbital tuning used as an age model?

A

Variations in earths eccentricity and obliquity and precession control the latitudinal of solar insolation received by earth
Processes leave a cyclical imprint in high resolution palaeoclimate records such as 13C and 18O

39
Q

What is eccentricity?

A

Shape of earths orbit

40
Q

What is obliquity?

A

Angle of earths orbit

41
Q

What is precession?

A

Direction of tilt of earth

42
Q

What carbon stores are released during hydrothermal events?

A

Methane hydrates
Permafrost
LIP Volcanism
Oxidation of peat or marine Corg

43
Q

What is the MMCO?

A

Middle Miocene Climatic Optimum
Brief warming period

44
Q

When did the uplift of the Himalayas start?

A

During the Eocene epoch

45
Q

When did the Antarctic continent become covered by an ice sheet for the first time?

A

Eocene/Oligocene Transition (EOT)

46
Q

What was the CO2 trend in the Eocene?

A

Long term atmospheric CO2 decline since the Early Eocene

47
Q

What are causes for Antarctic glaciation?

A

Declining atmospheric C02
Influence of orbital cyclicity
Antarctic circumpolar current

48
Q

How does orbital cyclicity cause Antarctic glaciation?

A

Orbital parameters favouring reduced seasonal contrast and cool summers in the southern hemisphere would enable continent-scale glaciation of Antarctica

49
Q

How does Antarctic circumpolar current cause Antarctic glaciation?

A

Opening of the Drake Passage resulted in development of the Antarctic Circumpolar Current (ACC) and thermal isolation of the Antarctica by the Eocene/Olgiocene Transition

50
Q

What is the more rapid decrease of CO2 since the end of the Miocene linked to?

A

Further increases in weathering and decreases in outgassing
resulted in onset of widespread northern hemisphere glaciation

51
Q

What is the duration of glaciation cyclicty?

A

41kyr

52
Q

When did the glacial-interglacial cycle intensify and switch to 100kyr cyclicity?

A

Since 1Ma, following the Mid-Pleistocene Transition (MPT)

53
Q

What 41kyr cycles forced by?

A

Obliquity
Tilt of axis from 22.1 to 24.5 degrees with a periodicity from one to the other and back again of 41kyr

54
Q

When do glaciations take place in terms of obliquity?

A

During low obliquity when seasonal contrast is reduced allowing milder/wetter winters (favouring snow accumulation) and cooler summers (limiting snow melt)

55
Q

What are methods and archives used to analyse Quaternary climate change?

A

Ice cores
Pollen assemblage
Foram assemblage
d13C and Circulation

56
Q

What are the accumulation rates of ice in Greenland and Antarctica?

A

Greenland: ~50cm/yr
Antarctica: <5cm/yr

57
Q

What do air bubbles in ice do?

A

record atmospheric composition based on 18O

58
Q

What causes different d13C in water?

A

Different histories of photosynthesis/respiration

59
Q

What is stadial?

A

Cold periods

60
Q

What are interstadials?

A

warm periods

61
Q

What does rapid climate change in N Atlantic foram assemblage indicate?

A

Indicates extreme cooling in North Atlantic as only the polar-dwelling species N. pachyderma survuves

62
Q

What is the AMOC?

A

Atlantic Meridional Overturning Circulation

63
Q

What is deep water formation controlled by?

A

Sea water density

64
Q

What is water density controlled by?

A

Controlled by temperature and salinity

65
Q

What does the Gulf Stream do?

A

Brings warm, saline surface water to the North Atlantic, which cool as they meet cold currents from the Artic

66
Q

What weakens the AMOC?

A

Freshwater input

67
Q

What are the three models of overturning?

A

Interstadials/modern: strong deep AMOC=warm
Glacial background: weaker shallower AMOC = cool
Stadial: Collapsed AMOC = very cold

68
Q

What was the Younger Dryas stadial?

A

End of deglaciation ~12ks
Last time scotland had ice sheets - glacial readvance
Controlled largely by moisture availability

69
Q

What is the Bipolar seesaw?

A

Reduced AMOC = Northern Hemisphere dramatically cooled due to limited ocean heat transport northwards
Conversely, Southern high latitudes warmed at the same time due to collapse AMOC

70
Q

What was the global impact of the collapse of the AMOC?

A

Shift in thermal equator and atmospheric circulation

71
Q

What is evidence of shift in thermal equator and atmospheric circulation?

A

Southward shift of storm track recorded by SW USA lakes
Southward shift of ITCZ recorded by Brazilian stalagmites and Cariaco basin runoff
Weakened monsoons in Asia recorded by stalagmites

72
Q

Why does methane jump up during interstadial?

A

Bog Respiration?
Permafrost melt?

73
Q

What is the inter-glacial CO2 change?

A

Enhanced biological pump exported larged amounts of organic carbon from photosynthetic algae to the deep southern ocean during glacial episodes
increased overturning during the deglaciation led to release of carbon from the deep ocean

74
Q
A
75
Q

What makes up anthropogenic climate change?

A

75% burning of coal oil and gas
25% Changes in land use

76
Q

When was the last time global surface temperature was sustained at or above 2.5 degrees?

A

3Ma during the Mid-Pliocene warm period

77
Q

When will we experience sustained 2.5 degrees warming?

A

By 2100 if ghg emissions stay closed to todays levels

78
Q

What were the main characteristics of the mid Pliocene warm period?

A

Global mean surface temperature was 2.5-4 degrees
Biomes expanded polewards
Higher precipitation
Stronger monsoons
Sea level 5-25m higher than present
Reduced ice sheets

79
Q

Is there a link between extinction and CO2?

A

Yes

80
Q

Why is there ocean deoxygenation during high CO2?

A

Increased nutrient supply from weathering
Phytoplankton blooms

81
Q

What is expected to happen to the AMOC with increased CO2?

A

Weakens
Low confidence in magnitude of weakening

82
Q

What would the collapse of the AMOC mean?

A

Southward shift of the ITCZ
Weakening of African and Asian monsoons
Strengthening of southern hemisphere monsoons
Drying of Europe

83
Q

What is the Kaya identity?

A

CO2 emissions = Population x GDP/Population x Energy/GDP x Carbon/Energy

84
Q

What are anthropogenic sources of climate change?

A

Electricity 25%
Land use and agriculture 24%
Industry 21%
Transport 14%
Buildings 6%
Fuel extraction 10%

85
Q

What is the solution to anthropogenic sources of CO2?

A

Clean electricity
Protect and plant trees
Reduce meat consumption
CO2 capture

86
Q

What is NETs?

A

Negative Emissions Technologies

87
Q

How can we remove CO2?

A

Terrestrial ~10s years
Oceans ~ 100s years
CaCO3 ~ 1000s years
Weathering ~100,000s years

88
Q

Which of the following is not likely to be associated with purely mantle derived volcanic emissions form an large igneous province:
Ocean acidification; global warming; ocean anoxia; increasing continental weathering rates; acid rain; major negative carbon isotope excursion.

A

Major negative carbon isotope excursion

89
Q

Which two mass extinctions are the Viluy and Siberian Traps LIP associated with respectively?

A

Late Devonian
Permian Triassic

90
Q

Which of the following carbon stores which could have contributed to early paleogene hyperthermal events is NOT sensitive to cyclical changes in earths orbit:
Thermogenic methane; biogenic methane hydrates; permafrost; peat

A

Thermogenic methane

91
Q

What was the early Eocene hothouse forced by?

A

High atmospheric CO2 levels from Deccan Traps

92
Q

What are the properties of surface waters in the North Atlantic which cause them to sink and drive modern thermohaline circulation?

A

Cold and saline

93
Q

True or false:
Dissolution of calcium carbonates in the ocean leads to a reduction in atmospheric CO2

A

True

ES2001 (9 decks)

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