Late Pleistocene - Holocene climate variations

over central Europe reconstructed from

groundwater data

J.A. Corcho Alvarado

Institute of Radiation Physics, Univ. Hospital and Univ. of Lausanne, Switzerland

R. Purtschert, M. Leuenberger

Climate and Environmental Physics, Univ. of Bern, .Switzerland

R. Kipfer

Dep. of Water Resources and Drinking Water, EAWAG, Switzerland

Institute of Geochemistry and Petrology, ETH Zurich, Switzerland

University of Bern

Outline

1. Reconstruction of past climate conditions from

groundwater data: a short introduction

2. Groundwater ages in investigated aquifers of the

Bohemian Cretaceous Basin

3. Reconstruction of past climate conditions

4. Conclusions

Climate Recharge conditions

Precipitation

(P)

P

Re

Groundwater

Soil Humidity

(Recharge rate)

Groundwater

Soil

Temperature

Re

Groundwater as a climate proxy

Water table

fluctuations

Recharge-Precipit.

Humidity

So

lub

ilit

y

Temperature

Aquifer

W

E

L

L Quasi-

saturated

zone

Noble gases (He, Ne, Ar, Kr, Xe)

1. Reconstruct recharge temperatures:

NGT-noble gas recharge temperature

2. Reconstruct humidity conditions:

ΔNe- Excess air

Input of meltwater Inverse modeling of the observed noble gas

concentrations is used to interpret the data in

terms of recharge temperature and excess air.

Stable isotopes (2H and 18O ) as paleoclimate proxies

– Reconstruct paleotemperature (T effect)

– Reconstruct paleoprecipitation (amount effect)

Stute and Schlosser, 2001. Atmospheric noble gases, in Environmental tracers in subsurface

hydrogeology, Cook and Herczeg (ed). Kluwer Academic Publishers

Low resolution paleotemperature record

Recharge

area

Discharge

area

Aquifer

Alpine ice field

Scandinavian ice sheet

Bohemian Cretaceus

Basin

EUROPE: last glacial maximum

Ice age Earth at glacial maximum. Based on: "Ice age terrestrial carbon changes revisited" by

Thomas J. Crowley (Global Biogeochemical Cycles, Vol. 9, 1995, pp. 377-389

A key region for understanding late Pleistocene

climate and glacial development

a) A large number of small

glaciers developed in the

Krkonose Mountains

b) The basin was covered by

discontinuos permafrost

Cenomanian and Turonian sands aquifers, Czech Republic

Vltava river

Prague

Mlada Boleslav

Turnov

Liberec

Zivonin syncline

Duba syncline

VP7502

VP7506

VP7500

VP7515

VP7517

VP7519

Karany B

VP7523

VP7512

VP7524

VP7520

N

S

- - - - - - Important faults

Wells in the Cenomanian sandstone

Wells in the Turonian sandstone

Flo

w d

irecti

on Uranium

mining

1. Noble gases: He, Ne, Ar, Kr, Xe

2. Stable isotopes: 2H, 18O, 13C

3. GW dating tracers: 3H/3He, 85Kr, 39Ar, 14C

4. Hydrochemistry, etc.

0 10 20 30 40 50 60 700

5000

10000

15000

20000

25000

30000

14C

ag

e (

yrs

.)

Distance from recharge (km)

Piston-Flow Model

An average ground water flow

velocity within the aquifer of

2.3 m/y is estimated.

0 10 20 30 40 50 60 700

10

20

30

40

50

60

Mixture

Input of

mantle CO2

14C

in D

IC (

pm

C)

Distance from recharge (km)

14C activity vs distance from recharge 14C age vs distance from recharge

Initial 14C ages were

corrected with the 39Ar ages

Spreadsheet, NETPATH and PHREEQC

calculations were performed to account for

chemical reactions and isotope exchange.

0 5000 10000 15000 20000 25000 30000

5.0x10-6

1.0x10-5

1.5x10-5

Aquifer accum. rate (calculated)

2E-11 cm3STPHe/cm

3water/yr

[4He] = 4.8E-10 * (Age) + 1.6E-7

R = 0.99

[4H

e]

(cm

3 S

TP

/g w

ate

r)

14C age (yr)

The 14C model ages are further confirmed by the linear

correlation with the concentrations of radiogenic 4He .

Vertical flux of helium from

deeper formations

Piston-Flow Model

Concentration of 4He vs 14C age

Age distribution along the flow direction

Last ice age

Flow velocity: 2.3 m/yr

-83

-79

-75

-71

-67

-63

-12.0

-11.5

-11.0

-10.5

-10.0

-9.5

-9.0

0 10000 20000 30000

δ2H

(‰

)

δ1

8O

(‰

)

14C age (yrs)

Oxygen-18

Deuterium

LG

M

Low resolution stable isotope (18O and 2H) records

1. Depleted δ18O and δ2H

during the LGM confirm

low air temperatures

2. Depletion consistent with

isotope shift in the ocean

surface during the LGM

Stute and Schlosser, 2001.

0

2

4

6

8

10

10 100 1000 10000

NG

T (

oC

)

14C age (yrs)

Low resolution noble gas temperature (NGT) record

LG

M

LGM

NGT = 0.8 oC

ΔT

~ 5

0C

Pre-industrial

Holocene

Late Holocene

(Modern)

ΔT

~ 7

0C

1. Low NGT of just above the

freezing point during the LGM

2. Glacial/interglacial warming

of 5 to 7 oC

The closed-system equilibration (CE) model was used to describe the

NGT and excess air component (Aeschbach-Hertig et al., 2000).

Ice covered/permafrost region -> No Infiltration during LGM, etc.

Coastal areas: large variations of air Temp.

Glacial/interglacial shifts in Europe, groundwater

Bath et al., 1979; Rudolph et al., 1984; Stute and Deák, 1989; Beyerle et al., 1998; Huneau et al., 2002; Zuber et al., 2000; Vaikmäe, 2001; Zuber et al., 2004; Blaser et al., 2010; Varsanyi et al., 2011

0

20

40

60

80

100

120

140

10 100 1000 10000

ΔN

e (

%)

14C age (yrs)

Excess air in groundwater (expressed as ΔNe)

LG

M

High excess air in

GW during the LGM

a) meltwater input?

- Pure meltwater: ΔNe > 500 %

- Stable isotopes: not highly

depleted

- Recharge of large amounts of

another water component

Typical in

groundwater:

10-50 %

b) Increased water table

fluctuations and hydraulic

loading due to frequent

intense rain events?

During the LGM:

a) The climate was dry, with air temperatures near freezing point

b) A large number of small glaciers developed in the Krkonose Mountains (Recharge area)

c) The Bohemian basin was covered by discontinuos permafrost

c) Abrupt change in recharge

dynamics?

- progression and retreat of ice

covers and permafrost

4

6

8

10

12

14

0 20 40 60 80 100

De

ute

riu

m e

xc

ess

( ‰

)

14C activity (pmC)

MA - Cracow, Poland

CA + TA - Czech Republic

Modern

Gla

cia

l

Present days

d-excess= 8.6 in precipitation

Deuterium excess in groundwater

Temporal decrease of deuterium excess from

pre-industrial Holocene to present days

d = -0.33 (NGT) + 11.12R² = 0.21

0

2

4

6

8

10

12

14

0 2 4 6 8 10

d e

xce

ss (

‰)

NGT (oC)

Decrease of deuterium excess linked

to an increase of air temperatures

Froehlich et al., 2002

MA – Oligocene Mazonian basin (Poland) (Zuber et al., 2000)

Conclusions

1. The low resolution NGT-record indicated a glacial cooling of at least 5 –

7 °C for the Bohemian Cretaceous Basin region, consistent with other

studies in Europe.

2. A high excess air (ΔNe) in groundwater at the end of the Pleistocene is

possibly related to changes in the recharge dynamics of groundwater

by the progression and retreat of ice covers and permafrost

3. A temporal decrease of deuterium excess in groundwater from pre-

industrial Holocene to present days is linked to an increase of the air

temperatures

Thank you for

your attention!!!