The intensification of the North
Hemisphere Glaciation :
Interaction between climate, vegetation and
oceanic circulation in the Northwest North
Atlantic
AURÉLIE AUBRY
SUPERVISORS : ANNE DE VERNAL & CLAUDE HILLAIRE-MARCEL
CONTEXTQ
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Lisiecki & Raymo (2004)
Ice
temperatures
T
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High-amplitude glacial-interglacial fluctuations
Recurring Northern Hemisphere ice sheets
Sea level decrease, -20m, (IPCC, 2013)
Greenland vegetation
evolution
Arctic tundra
pCO2 atm ~280 ppmv during Pleistocene (Seki et al., 2010)
pCO2 atm ~401 ppmv july 2015
INTENSIFICATION OF THE
NORTH HEMISPHERE
GLACIATION
Only local ice sheet in North Hemisphere
Warmer temperature + 0-6°C (IPCC, 2013)
pCO2 atm ~380 - 400 ppmv (IPCC, 2013)
pCO2 atm max 425 – 450 ppmv climatic optimum
Boreal forest
OBJECTIVES
Status of Greenland ice ?
Interaction between climate, vegetation and oceanic circulation in the Northwest
North Atlantic
OBJECTIVES
Status of Greenland ice ?
Interaction between climate, vegetation and oceanic circulation in the Northwest
North Atlantic
3 time intervals :
3
1.1 to 1.03 Ma
Pleistocene
Last time interval with
same astronomical
parameters (40 ka
cycles)
2
2.6 to 2.8 Ma
Pliocene/Pleistocene
Terciary/Quaternaty
transition and
intensification of the
North Hemisphere
glaciation
1
3.3 to 3 Ma
Pliocene
Climatic optimum
OBJECTIVES
Status of Greenland ice ?
Interaction between climate, vegetation and oceanic circulation in the Northwest
North Atlantic
1
The Greenland boreal forest
2
Surface condition, interaction and evolution
between the Baffin Bay and the Labrador Sea
3
Weathering, proximal input and transport by
marin current un the Labrador Sea and the Baffin
Bay
MATERIAL
Labrador Sea & Baffin Bay
Marine cores
ODP 645
70.4572°N, -64.6543°O
Water depth = 2020 m
ODP 646
58.2093°N, -48.3691°O
Water depth = 3400 m
IODP 1307
58.5058°N, -46.4005°O
Water depth = 2575m
Surface currents :
Deep currents :
WGC : West Greenland Current
BIC : Ban Island Cuyrrent
LC : Labrador Current
NAD : North Atlantic Drift
LSW :Labrador Sea Water
NADW :North Atlantic Deep Water
WBUC : Western Boundary UnderCurrent
METHODS
Palynology
Geochemestry
Marine
Terrestrial
Dinocysts
Pollen grains & spores
o  Bulk composition
o  Clay mineralogy
Dinoflagelate =
phytoplancton with
ecologic affinities and
produce a fossilisable
cyst during life cycle
Main taxa from
adjacent lands
transported by wind
and river to the ocean
o  Laser granulometry
o  IRD
Qualitative oceanic
conditions
Operculodinium centrocarpum
Invertocysta lacrymosa
Qualitative continental
conditions
Corylus sp.
Pinus sp.
Continental weathering
conditions and marine
currents
PRELIMINARY RESULTS: IODP 1307
PRELIMINARY RESULTS: IODP 1307
Palynology : concentration
² Acritarcha
dominance
² High concentration
of reworke
palynomorphs
² Very low foraminifer
linings
² Lot of silicate in the
sample
=> Heavy liquid
method is the best
PRELIMINARY RESULTS: IODP 1307
Palynology : dinocyst assemblages
Brigantedinium sp.
Brigantedinium sp.
O. centrocarpum
Bitectatodinium sp.
N. labirynthus
PRELIMINARY RESULTS: IODP 1307
Palynology : acritarcha
C. invaginata
C. fensomei
L. canalis
C. invaginata
C.? aegirii
L. crista
PRELIMINARY RESULTS: IODP 1307
Palynology : pollen grains & spores
Boreal forest
Pinus sp
Herbs
Shrub
Tree
Corylus sp
Piceae sp
Quercus sp
Tsuga sp
•  Thank you