GEOL 4010 QUATERNARY GEOLOGY Instructor: Dr' Hester Jiskoot

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GEOL 4010QUATERNARY GEOLOGYInstructor Dr.
Hester Jiskoot
LECTURE 11
Sea level curves
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Lab 3 sea level curve interpretation well done!
You can find the answers for Lab 3 in Benn and
Evans, 1990. Glaciers Glaciation. Pages 32-39.
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(No Transcript)
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SEA-LEVEL CURVES and REBOUND
Total recovery
Rebound-residual
CRUST glacioisostacy hydroisostacy Depression
Hice(?ice/?mantle)
Rebound-postglacial
Amount of crustal rebound
Rebound-restrained
?Time since deglaciation
WATER glacio eustacy geoidal eustacy steric
(ocean warming)
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RELATIVE SEA LEVEL AND INSOLATION
Lambeck et al. (2002)
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MIS-3
Sea level Marine ?18O Ice Rafted Debris
(IRD)-peaks
Neogloboquadrina Pachyderma (s.)
Lambeck et al. (2002)
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ESTABLISHED SEA LEVEL CURVES
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Australia (Yokoyama, 2000)
Barbados (corrected by ?)
Barbados
New Guinea
Tahiti
Marine ?18O
Atmospheric CO2
Sea level estimates compared to marine ?18O
atmospheric CO2 records. (Clark and Mix, Nature,
2000)
? Lag of 3000 years between sea level and ?18O
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Old data shows a closer match
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Estimates of excess ice-equivalent sea level for
LGM ice sheets (m) CLIMAP Min Max Ice sheet
Min Max Peltier ANU Milne et al. Antarctica
24.5 24.5 14.0 21.0 17.6 North America 77.0
92.0 82.4 82.4 64.3 Greenland 1.0 6.5 2.0
3.0 6.0 Scand/Barents 20.0 34.0 13.8 18.0
25.5 All others 5.0 6.0 6.0 6.0 Total
127.5 163 118.2 130.4 113.5 130135
115135
Sea level data
CLIMAP (1981) modelling ? min ? ice is restricted
to continental margins Ice Sheet (1999-2002)
recent ice sheet models Peltier (2002) ANU
(Lambeck, 2002) Milne et al. (2002) allows for
changes in area of ocean basins since LGM
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127.5 m eustatic sea level
CLIMAP min. ice cover ? Ice sheet restricted to
continents
163 m eustatic sea level
CLIMAP max. ice cover
Single-domed LIS wrong!
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How can sea level curves help us to reconstruct
detailed ice sheet margins?
Norway

• Data points observed sea level
• Lines models
• max ice margin to shelf
• max ice margin only to present coast

Baffin island
Lambeck et al. (2002)
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Observed and modelled sea levels (Lambeck, 1996)
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UNCERTAINTIES IN SEA LEVEL FLUCTUATIONS
Ranges of uncertainty for the average rate of sea
level rise from 1910 to 1990 and the estimated
contributions from different processes. (IPCC,
2001)
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Reading for Friday pages 119-134