- Past climate changes : general presentation and tools
- Antarctic ice cores : from Byrd to Vostok-
- Greenland ice cores : from Camp Century to GRIP/GISP2- Historical overview- GRIP and GISP 2 rapid changes
- Dating strategy Isotope :temperature- Dating strategy
- Rapid changes in the North Atlantic- Geographical extension of rapid cahnges- Greenland / Anatarctica- The 8.2 K event
- Ongoing projects : EPICA, North GRIP and others
GRIP and GISP2 (Central Greenland) ; North GRIP
Les forages glaciaires
au GROENLAND
-44
-40
-36
-32
10080604020Age [kyr BP]
-44
-40
-36
-32
18O
[‰
]
-44
-40
-36
-32
-44
-40
-36
-32
GRIP ss09 ages 50 yr
GRIP ss09sea ages 50 yr
GISP2 "counted" and SPECMAP
GRIP stratigraphic chronology
GRIP/GISP2 time scale comparison
Below 2700 m (~ 100 000 years) the two profiles diverge due to ice flow disturbances
12
10
8
6
4
2
d (deut excess)
‰
16151413121110age (kyr)
-320
-300
-280
-260
D
(‰/s
mow
)
GRIPD
d excess
YD
The last deglaciation
d = D - 8 * 18O
12
8
4
d (deut excess) ‰
6050403020age (kyr)
-320
-280
D (‰
/sm
ow)
GRIPD
d excess
The glacial period : the Dansgaard / Oeschger events
D0 8D0 12
-42
-40
-38
-36
-34
-32
18O
(‰)
2600
2500
2400
2300
2200
2100
2000
1900
1800
1700
1600
1500
1400
1300
Depth (m)
25
20
15
10
5
0
Temperature change
14.5 21 34.8 68.5
YD
Bølling
LGM
D/O9 D/O19
HOLOCENE
8.2 11.6
GRIP Ice Core 20°C
Review of independent temperature estimates : Jouzel (1999)Differences largely due to seasonality (Krinner et al., 1997 ; Werner et al., 2000)
1716151413121110
Calendar Age (ka)
0.25
0.20
0.15
0.10
0.05
GISP2 A
ccumulation (m
/yr)
-42
-40
-38
-36
-34
GIS
P2
18O
ice
(‰)
0.60
0.50
0.40GIS
P2
15N
(‰)
700
600
500
400
Methane (ppbV)
GISP2 Taylor Dome
Severinghaus et al. (Nature, 1998)Severinghaus and Brook (Science, 1999)
Rapid 15N changes caused by thermal and gravitational processes
Combined use of 15N /14N and 40Ar/ 36Ar isotopic ratios allows precise estimate of the associated temperature change
Comparison of the ice and gas records allow direct estimate of the firn thickness and of the gas age/ ice age difference
Direct comparison of gas records (e.g. CH4, CO2 ….) with rapid temperature change
Method also useful for Antarctica(Cf Caillon et al., Science, 2003 who inferred the timing between CO2 and temperature change at Termination 3
Le névé
18Oglace et Dglace
= f (T°C)
Zone convective
Zone diffusive
Zone non-diffusiveCLOSE-OFF
névé
glace
même âge
âge
Dans les bulles d'air : Age de l'air différent de l'âge de la glace : âge
40Ar et 15N = f ( T°C , Accumulation…) [CH4] , [CO2], 18Oatm …
Le névé
18Oglace et Dglace
= f (T°C)
Zone convective
Zone diffusive
Zone non-diffusiveCLOSE-OFF
névé
glace
même âge
âge
Dans les bulles d'air : Age de l'air différent de l'âge de la glace : âge
40Ar et 15N = f ( T°C , Accumulation…) [CH4] , [CO2], 18Oatm …
Zone convective
Zone diffusive
Zone non-diffusiveCLOSE-OFF
névé
glace
même âge
âge
Zone convective
Zone diffusive
Zone non-diffusiveCLOSE-OFF
névé
glace
même âge
âge
Dans les bulles d'air : Age de l'air différent de l'âge de la glace : âge
40Ar et 15N = f ( T°C , Accumulation…) [CH4] , [CO2], 18Oatm …
1819
20
40Ar and 15N measurements combined with a firn model allow precise estimates of Tsite : 10°C (18 and 20), 15°C (19) ;
Landais et al. (In preparation)
North GRIP
Rapid changes in the North Atlantic
Découverte de variations climatiques rapides dans le passé ( ~ 10°C en quelques décennies)Groenland, atlantique nord, continents..
Modifications du cycle hydrologiqueliées à la décharge massive d’icebergs
Risque de surprise climatique dans un climat plus chaud (apport d’eaudouce à travers des précipitations
Geographical extension of rapid changes
1000 1100 1200 1300AS96-1NR [depth, cm]
-8
-7
-6
-5
-4
18Ocs M
id-Europe [‰ PDB]
5000 6000 7000 8000 9000 10000 11000 12000 13000 14000 15000GRIP Ice-core chronology [years] -42
-41-40-39-38-37-36-35-34
18Oice Centr.Greenl. [‰ SMOW]
500 600 700 800 900 1000AS92-5 [depth, cm]
700 800AS93-1 [depth, cm]
Lake sediments in Bavaria, Germany ; von Grafensteinet al., Scienc, 2001
Genty et al. (Nature, soumis )
Stalagmite de la grotte de Villars
30000 35000 40000 45000 50000 55000 60000 65000 70000 75000 80000 85000
-10
-9
-8
-7
-6
-5
-42
-40
-38
-36
-44
-42
-40
-38
-36
-34
1
2
3
age yr
Vil9
C
GRIP
ss
09
Sore
q Cave
C
GISP
2M
D 95- 2
042
-10
-9
-8
-7
-6
-5
Hulu
Cave
,
-12-11-10-9-8-7
7 810
11
12
1314
16 1719 20
6 78
9 10 1112
13
1416
17
18
19 20
8 101112
7 1314 16 17
18
19 20
7 8 10 11 12 13 14 1617
192010
11 12 13
8 12 1419 20
D2D3D4 D1D5D6D7
H6H5b
Plan
k.
2012
GRIP
ss09
sea
French cave200 km from the ocean
Genty et al. Nature, 2003
Hulu Cave, East of Nanjing (China) :Wang et al. (Science, 2001)
Dongge cave, Guizhou Province : Yuan et al. (Science, 2004)
Greenland / Antarctica
Blunier and Brook, Science, 2001
Corrélations Nord-SudDe 10 000 à 90 000 ans
8.2 K event : a rapid event cooling during a warm periodThe day after tomorrow
2.00
1.95
1.90
1.85
40Ar (‰
)
15801560154015201500profondeur (m)
-480
-475
-470
-465
-460
-455
-450
D
(‰)
650
600
550
500
450
CH
4 (p
pbv)
0.49
0.48
0.47
0.46
15N
(‰)
prof = 32 m
âge ~ 5100 ans
prof = 64 ± 2 m
âge ~ 2500 ans
âge ~ 2600 ans
D CH4 (1999) CH4 (1990)
40
Ar
15
N
Caillon et al., unpublished
Le sud se réchauffe avant le Nord sur toute la dernière période glaciaire avec une
avance de ~2000 ans.
Rôle important joué par la circulation océanique et
l’intensité de la circulation thermohaline dans l’hémisphère Nord.
Corrélations Nord-SudÉtude de la transition 5d/5c (108 000 ans)
Raisbeck et al., Goldschmidt Conference, 2002
The 10Be peak straddles event 10, exactly as seen in the GRIP core. This implies that, within our ability to resolve, which we presently estimate as 200 years, the GRIP and EPICA climaterecords at this time are synchronous.
Small events / Large events ? Interesting modelling approach ofJohnsen and Stocker, Paleoceanography, 2003
High resolution Vostok CH4 record shows millennial-scale variability during MIS 6 and MIS8 (periods of 2 to 7 kyr) : Delmotte et al., In prep , Chappellaz , Euresco, 2003
Detailed water isotope profiles combined with high resolution methane measurements should allow to extend the record of D/O events to previous glacials
5.04.54.03.53.0 foram
s 18O (‰
)
100
100
80
80
60
60
40
40
20
20
0
0
Age (kyr)
1.0
0.5
0.0
-0.5
18O at
m (‰)
-480
-460
-440
Vost
ok D
ice
-40
-35
-30 GISP2 18O
ice (‰)
700
600
500
400
GIS
P2 C
H 4 (pp
b)
8 12
14
16/1719 20
21
18
GISP2
Vostok
V19-30 benthics
GISP2 CH4
Vostok Dice
GISP2 18Oice
Bender.M., Malaizé, B.,Orchado, J., Sowers, T, Jouzel, J Geophysical Monograph , 1999
