Ice and sediment cores in paleoclimatology
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Transcript of Ice and sediment cores in paleoclimatology
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Ice and sediment cores in paleoclimatology
Samuel Masoni
Quentin Impagliazzo
Luci-Lou Hebert
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INTRODUCTION
INTRODUCTION
Ice cores Sediment cores (from the lake or from the sea-floor)
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Summary
INTRODUCTION
I- Ice Cores
1) Introduction
2) History of ice core research
3) Techniques used in ice core research and dating
strategies
4) Measurements performed on the ice
5) Dating Strategy
6) A general overview of climates of the past as seen
from ice cores and related proxies:
7) What past climates are relevant to modern-day and
future climate change?
8) What more research is needed? (Four challenges)
Summary
II- Sediment Cores
1) Lake Sediments
A/ What can we learn thanks to lake sediment cores
B/ Which methods are used to determine age within the core
2) Seafloor Sediments
A/ Drilling Techniques and Repartition
B/ Cores Identification and Description
C/ Sediment composition and geographic distribution
D/ Cores Dating
E/ Advantages and disadvantages of seafloor sediment cores
CONCLUSION
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I. Ice Cores
I. Ice Cores
1) Introduction https://www.youtube.com/embed/T69_diWYbkQ?rel=0
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2) History of ice core research
I. Ice Cores
1960 : Ice core research started 1st core drilling at Camp Century in Greenland GRIP (European) and GIPS2 (US) project Antarctica (Vostok, Dome C) EPICA (European Project for Ice Coring in Antarctica)
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3) Techniques used in ice core research and dating strategies
I. Ice Cores
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3) Techniques used in ice core research and dating strategies
I. Ice Cores
DIFFICULTIES: The access to the drilling site The extreme climatic conditions The need to use a drilling fluid to prevent the hole from closing The improvement of drilling techniques
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4) Measurments performed on the ice
I. Ice Cores
Which Climate Properties Do We Have Access to ?
Temperature
Accumulation rate
Origin of the precipitation
Atmospheric composition
Other climate parameters
Volcanic and solar forcings
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5) Dating Strategy
I. Ice Cores
1) Layer counting (only for Greenland, not for Antarctica)
2) Glaciological modeling
3) Use of time markers correlation
4) Comparison with insolation changes (orbital tuning)
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6) A general overview of climates of the past as seen from the ice cores and related proxies
I. Ice Cores
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I. Ice Cores
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I. Ice Cores
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I. Ice Cores
7) What past climates are relevent to modern-day and future climate change ?
Anthropogenic perturbation
Greenhouse gas concentration never been so hight
Projected climate change compare to past climate change
Future climate change = abrupt events
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I. Ice Cores
8) What more research needed ? 4 Challenges
1) The first Challenge : Obtain an undisturbed Antarctic ice core climate record prior to 1.2 million
years ago
2) The second Challenge : Obtain an undisturbed Greenland ice core climate record covering the
integrity of the last interglacial periods
3) The third Challenge : The full description of millennial scale variability
4 ) The final Challenge : The ultra-high-resolution records of climate variability and climate
forcings spanning the past 2000 years
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II. Sediment Cores
II. Sediment cores
1) Lake sediments
A/ What can we learn thanks to lake sediments cores ?
Water level (the depth of flowing water).
Lake drying
Frost
Oxygenation
Exceptional events
Living conditions for organisms in the lake
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II. Sediment Cores
B/ Which methods are used to determine age within the core ?
Magnetic Reversal
Tephrochronology
Radiocarbon Analysis
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II. Sediment Cores
2) Seafloor Sediments
A/ Drilling Techniques and Geographical Repartition
Drilling techniques
- Difficulty : keep the sediment compact
- Different techniques for different kinds of sediments
Expedition and price:
- A common expedition
- Drilling speed : 1 m/h
- Drilling cost : 3500 $/m
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II. Sediment Cores
A/ Drilling Techniques and Geographical Repartition
Geographical repartition :
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II. Sediment Cores
B/ Cores Identification and Description
How to identify cores :
- LEG : which expedition
- SITE: where
- HOLE : which hole
- CORE: how deep
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II. Sediment Cores
B/ Cores Identification an Description
How to describe cores:
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II. Sediment Cores
C/ Sediment composition and geographic distribution Type of sediments Origin of sediments Sediment Map
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II. Sediment Cores
D/ Cores Dating
Biostratigraphy (microfossils)
Magnetic Reversal
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II. Sediment Cores
E/ Advantages and disadvantages of seafloor sediment cores
Advantages - Old enough to record the
Cenozoic sediments
- Can be dated
- Large geographical repartition
- Many types of information
Disadvantages
- High cost
- Some discontinuity
- Technical difficulties
-Low resolution
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CONCLUSION
CONCLUSION
Ice cores: - 123 000 (greenland) to 800 000 years (antartica) - Global geographic scale - High resolution Lake sediment cores: - 800 000 years - Local geographic scale - High resolution
Seafloor sediment cores : - 100 millions years - Global geographic scale - Low resolution
Reconstruct the past climates plan the futur climates
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Bibliography
BIBLIOGRAPHY
Jouzel, J., & MassonDelmotte, V. (2010). Paleoclimates: what do we learn from deep ice cores?. Wiley Interdisciplinary Reviews: Climate Change, 1(5), 654-669.
Menking, K. M. (1995). Paleoclimatic Reconstruction's from Owens Lake Core OL-92, Southeastern California (No. AFRL-SR-BL-TR-98-0026). Air force research lab bolling afb dc.
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Worksheet correction
Which Climate Properties Do We Have Access to ?: What are the 4 challenges in ice core research? : Which clue can give information about :
Water level (the depth of flowing water) Lake drying Frost Oxygenation Exceptional events Find the correct number :
Drilling speed : .. m/h Drilling cost : .... $/m
Which information gives :
LEG : SITE: HOLE : CORE: Examples of information listed in the table:
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Will we survive ? In which conditions ?
How do you imagine our future ?
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Thank you for your attention