activity in the coversand area near Eindhoven, The Netherlands

(1)

Environmental conditions round a Lateglacial lake facilitated Late Palaeolithic Environmental conditions round a Lateglacial lake facilitated Late Palaeolithic activity in the coversand area near Eindhoven, The Netherlands

activity in the coversand area near Eindhoven, The Netherlands

A.H.Geurts@uu.nl

A.H.Geurts@uu.nl ǀǀ Department of Physical Geography, Faculty of Geosciences, Utrecht University, The Netherlands Department of Physical Geography, Faculty of Geosciences, Utrecht University, The Netherlands

Introduction Introduction

At

southern and

continuously archaeological

Younger

Younger Dryas Dryas Holocene Holocene drift

drift sands sands

Cryoturbated

Cryoturbated Pleniglacial Pleniglacial

Lateglacial

Lateglacial--Holocene Holocene lake lake--fill fill Pleni Pleni--Lateglacial Lateglacial coversand coversand sequence

sequence

archaeological called

fig

adjacent presence camps lake

in relation

reconstructing developments transition

Allerød Allerød – – Younger Dryas Younger Dryas

soil

soil horizon horizon Younger

Younger Dryas Dryas aeolian

aeolian sands sands

Figure 1 Photographs from the excavation pits, showing the lake-fill and coversand stratigraphy and cryoturbation structures which are present below the lake-fill.

Lateglacial

Lateglacial lake lake--fill fill stratigraphy stratigraphy

The lake-fill stratigraphy starts with lightbrown very fine detrital loamy gyttja at the base, directly on top of the coversand substrate. The lower part of this facies has a laminated character due to the intercalation of clastic layers (fig 5). At the upper end, a sharp interface exists with a darkbrown peat layer (LOI 40- 50%). On top of that lies a darkbrown loamy gyttja layer with a higher organic content than the lower gyttja unit (~12% vs ~5%). The stratigraphy ends with a

Lateglacial lake Lateglacial lake--fillfill Holocene peat Holocene peat

gyttja unit (~12% vs ~5%). The stratigraphy ends with a sandy peat layer (blackish; fig 1,2). In this region, lithological changes can be explained in terms of changing intensities in local reworking of sediments (mainly wind- and surface-runoff-driven) and organic productivity.

Loss-on- ignition

Figure 3 Summary pollen diagram from one of the cores retrieved from the central and deepest part of the Lateglacial lake at Aalsterhut (fig 2). Awaiting radiocarbon dating results, chronology has been based on biostratigraphic correlation to the well-dated regional pollen zonation scheme of the Netherlands (Hoek 1997).

Landscape

Landscape development development

The combined picture shows that a shallow lake initially formed during the Bølling interstadial at

of first postglacial climatic warming and vegetation recovering (loamy gyttja). During the early stage

Allerød, relative lake-level lowering caused Palaeolithic settlements to be located northeast of a swamp

very shallow lake (peat formation). Under influence

Figure 4: Reconstructed lake-level history over the Lateglacial period for the Aalsterhut site plotted together with the periods of Palaeolithic settlements.

Archaeology

very shallow lake (peat formation). Under influence a rising groundwater table a lake setting became

established in the course of the Allerød and continued to exist during the entire Younger Dryas. Enhanced clastic input recorded in the loamy gyttja unit evidence stadial climatic conditions and a more open landscape during the Younger Dryas, however, does not indicate large-scale aeolian coversand reworking Cryoturbation features indicate deep-seasonal

have occured during Younger Dryas times.

Conclusions Conclusions Conclusions Conclusions

• Initial lake formation around onset Bølling

• Longterm increase in groundwater/lake level over the Lateglacial period

• Temporal (relative) early Allerød lake-level drop

• Relative stable Younger Dryas vegetation cover and landscape, inhibiting large-scale sediment reworking

• Birch dominant over pine during whole Lateglacial

• Lake-level reconstruction likely shows phenomena (e.g. permafrost melt) rather

climate signal as concluded from inconsistency

other lake-level reconstructions from the Netherlands

• High lake levels attracted Late-Palaeolithic cultures settle on the dry sand ridge

Anneleen

Anneleen H. H. Geurts Geurts and and Wim Wim Z. Z. Hoek Hoek

Environmental conditions round a Lateglacial lake facilitated Late Palaeolithic Environmental conditions round a Lateglacial lake facilitated Late Palaeolithic activity in the coversand area near Eindhoven, The Netherlands

activity in the coversand area near Eindhoven, The Netherlands

Anneleen

Anneleen H. H. Geurts Geurts and and Wim Wim Z. Z. Hoek Hoek

Department of Physical Geography, Faculty of Geosciences, Utrecht University, The Netherlands Department of Physical Geography, Faculty of Geosciences, Utrecht University, The Netherlands

Introduction

Introduction and and research research approach approach

a coversand ridge near Eindhoven in the southern Netherlands, Late Palaeolithic hunters and gatherers were locally repeatedly or continuously present as evidenced by numerous archaeological artefacts at and above the so-

The local lithostratigraphy, lake-fill distribution and palynological (pollen) record was studied by means of:

• ca. 200 borings

• 2 excavation pit studies

• 5 cross-sections across the lake archaeological artefacts at and above the so-

called Usselo soil horizon (Allerød-Younger Dryas;

1). A depression filled with organic sediments adjacent to the sand-ridge testifies to the presence of prehistorical hunting and fishing camps along the downwind shores of a former lake. This study aims to investigate human activity relation to environmental change by means of reconstructing local landscape and vegetation developments over the Weichselian to Holocene transition.

• 5 cross-sections across the lake

• 1 detailed lake-shore cross-section

• 4 cores: pollen, lithology and LOI

Awaiting

¹⁴

C dating results, local chronology has been inferred from biostratigraphic correlation with the well-dated Lateglacial pollen zonation scheme of the Netherlands (Hoek 1997).

Subatlantic driftsand Subatlantic driftsand

\

cryoturbation cryoturbation features

features (see also fig 1) (see also fig 1)

Subatlantic driftsand Subatlantic driftsand

SAND RIDGE SAND RIDGE

coversand and fluvial coversand and fluvial--

aeolian deposits aeolian deposits

Figure 2 Cross-section through the Lateglacial lake-fill and adjacent coversand ridge (top, for location see figure 5) and a detailed cross-section across the northern shore of the lake, including core/sample locations.

Holocene Holocene

Vegetation development

Vegetation development based on four records, including the one shown here based on four records, including the one shown here

Upland Local

establishment of a dense mixed forest, including thermophilous tree species

onset of Sphagnum peat formation

Younger Younger

Dryas Dryas

Allerød Allerød

Older Older Dryas Dryas Bølling Bølling Holocene Holocene

Late Late Pleniglacial Pleniglacial

open landscape with abundant heliophilous herbs and some birch trees, willow and juniper

open landscape, expansion of willow

expansion of birch tree and lateron pine, resulting in an open forest structure with a continues dominance of birch

opening of the mixed birch-pine forest, favouring herbs, grasses and crowberry

thermophilous tree species

scarce vegetation cover

onset of organic accumulation; pioneer vegetation with a dominance of (cyper-)grasses

well-developed wet-meadow vegetation fringing the lake supporting a rich aquatic flora

massive expansion of a horsetail-cypergrass communities at the expense of aquatic species, followed by the opposite trend

a relative low number of taxa along the shores as well as within the lake

scarce vegetation cover

lake was at times vegetation stage of the Palaeolithic swamp or influence of

Figure 5 Map showing the lateral distribution of different lithostratigraphic units, providing a reconstruction of changes in lake dimensions in time (top left). Photograph showing alterations in deposition of loamy gyttja and loamy sand during the phase of initial lake formation (top right). Digital Elevation Model image of the area around the Aalsterhut site (bottom).

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Bolling - Older Dryas

Allerod - Younger Dryas

Rhythmic alterations in deposition of loamy gyttja and Rhythmic alterations in deposition of loamy gyttja and loamy sand at the base of the Lateglacial lake

loamy sand at the base of the Lateglacial lake--fill sequence fill sequence Longterm Lateglacial increase in lake

Longterm Lateglacial increase in lake--level level and distribution of lake sediments and distribution of lake sediments

Bølling-OD Allerød - YD

two cores from deepest part of the lake

influence of became re- continued Enhanced evidence landscape indicate reworking.

frost to

abandoned abandoned Pleistocene Pleistocene

valley valley

Holocene Holocene lake/bog lake/bog sand

sand--ridge ridge dammed dammed Pleistocene Pleistocene

valley valley

Lateglacial lake Lateglacial lake

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0 25 50 100

meter

Allerod - Younger Dryas

(Early) Holocene

Netherlands Netherlands

Eindhoven

Early Holocene