ENVIRONMENT IN NW- -EUROPE DURING GREENLAND INTERSTADIAL 1 EUROPE DURING GREENLAND INTERSTADIAL 1

(1)

A-4

A-10 A-5

A-9

A-12 A-11

A-13 A-14

0 10M

173000

173000 174000

174000 175000

175000 176000

176000

367000

368000 368000

369000 369000

Legend High Low

gy

348 403 371 390 386 352 391

322 303 327 467 418 315 371 327373 333 358 288

317 343

326

p

LOCATIONS

THE EFFECT OF RAPID CLIMATIC OSCILLATIONS ON THE THE EFFECT OF RAPID CLIMATIC OSCILLATIONS ON THE ENVIRONMENT IN NW

ENVIRONMENT IN NW- -EUROPE DURING GREENLAND INTERSTADIAL 1 EUROPE DURING GREENLAND INTERSTADIAL 1

LEADS AND LAGS BETWEEN CLIMATE AND ENVIRONMENT LEADS AND LAGS BETWEEN CLIMATE AND ENVIRONMENT

Nelleke van Asch and Wim Z. Hoek

Department of Physical Geography, Faculty of Geosciences, Utrecht University. E-mail: N.vanAsch@geo.uu.nl

REFERENCES

Hoek, W.Z. and Joosten, J.H.J. (1995), Pingo-ruïnes en kalkgyttja in het Weerterbos, Natuur Historisch Maandblad 84-10, p. 234-241.

Hoek, W.Z. (2001), Vegetation response to the ~14.7 and ~11.5 ka cal. BP climate transitions: is vegetation lagging climate? Global and Planetary change 30, p. 103-115.

Rasmussen, S. O., et al. (2006), A new Greenland ice core chronology for the last glacial termination, J. Geophys. Res., 111, D06102, doi:10.1029/2005JD006079.

CORRELATION BETWEEN CLIMATE AND VEGETATION

Hoek (2001)

INTRODUCTION

Rapid climatic oscillations are recorded in the Greenland oxygen isotope records during GI-1 (the Bølling/Allerød Interstadial). What is the effect on the terrestrial environment?

RESEARCH QUESTIONS

• Did temperature changes during Greenland Interstadial 1 occur synchronous in a west-east transect?

• Can we determine a west-east gradient in the amplitude of temperature changes associated with a decreasing Atlantic influence?

• Did changes in vegetation occur synchronous to temperature changes?

METHODS

Multi-proxy analyses will be carried out on calcareous lake deposits along an west-east transect in NW-Europe. Analyses will comprise oxygen isotopes, pollen and chironomids, while AMS

¹⁴

C dating and tephra are used for correlation.

FURTHER RESEARCH PRELIMINARY CONCLUSIONS

The multi-proxy approach allows us to establish (a)synchroneity between climatic and related environmental changes:

Forest expansion took place AFTER the warmest part of the Interstadial (lag effect: migration, soil stabilization) The regressive phase in vegetation (KV-2b) is so far not visible in the δ

¹⁸

O record: not a climatic change?

-36 Age

(kyr BP)

OXYGEN ISOTOPES NGRIP, Greenland

-44 -42 -40 -38 14

15 12

13

δ¹⁸O ‰ SMOW GS 1

GI 1d GI 1b

Arboreal pollen (%) 15

12 11

13 14

0 100

POLLEN The Netherlands

Rasmussen et al. (2006)

Age (cal kyr BP)

?

OXYGEN ISOTOPES AND POLLEN Klein Ven, Weerterbos, The Netherlands

Can changes in vegetation be correlated to climatic oscillations?

N

10 km Maastricht Weert Weerterbos

peat peaty clay / clayey peat detrital gyttja calcareous gyttja soil concretions peaty sand / sandy peat silty sand / sandy silt sand

NNE SSW

29

28

27

26

m+O.D.

Site in The Netherlands:

• Klein Ven, Weerterbos, NW Limburg

• Circular depression (pingo remnant) in Pleistocene coversand

• Calcareous gyttja infill Sampling sites

CaCO3

Betula Pinus

AP NAP Ericales

Juni perus

Corylus Cyperaceae

Graminae Artemisia

Helianthemum Equisetum

Menyanthes Nymphaea

Potamogeton Pediastrum

Botryococcus pollens

um Salix

Lithology

2,00 1,80 1,60 1,40 1,20 1,00

Depth (m)

50 100-5 -3 -8-4 0 50 100 2020 100200 30 60 2010 20 1010 200 100 100 200

Isotopic correlation between NGRIP and Klein Ven

• KV-1 (δ

¹⁸

O high) can be correlated to GI-1e (warm)

• KV-2 (δ

¹⁸

O low) can be correlated to GI-1d+1c (colder)

Digitial elevation model of NW Limburg

Cross-section Klein Ven, Weerterbos Core

DEM: AHN, Rijkswaterstaat AGI Topography: Topographic Survey

zone

KV-3

KV-2a

KV-1

Hoek and Joosten (1995)

KV-2c

KV-2b

Higher resolution pollen and oxygen isotopes:

• Is the regressive phase in vegetation (KV-2b) visible in the δ

¹⁸

O record?

Chironomid analysis (reconstruction of mean July temperature):

• Is the transition from KV-1 to KV-2 induced by local factors or climatic change?

• Is the regressive phase in vegetation (KV-2b) the result of a lowering of summer temperature?

Tephra and AMS

¹⁴

C dating (chronology):

• Did changes occur synchronous at other sites?

(%) (‰ PDB) (‰ PDB) (%) (%) (%) (%) (%) (%)(%) (%) (%)(%) (%) (%) (%)

Vegetation development Klein Ven

• KV-1: Open herbaceous vegetation

• KV-2: Expansion of birch forest

• KV-2b: Regressive phase during forest expansion

GI 1c

GI 1e GI 1a

Klein Ven

δ¹⁸O δ¹³C