A new Middle Pleistocene interglacial occurrence from Ejby, Sjælland, Denmark

Ole Bennike,Peter Wiberg-Larsen

doi:10.34194/geusb.v49.8294

Abstract

Despite more than a century of investigations, parts of the Quaternary stratigraphy of Denmark with their fragmented record of deposits remain ambiguous. Here we describe a newly found interglacial clay deposit from Ejby on Sjælland, Denmark, from a borehole at 55.695°N, 11.839°E (terrain elevation 5.7 m above sea level). We place the new occurrence on record and provide details of the macrofossil analysis of the sample. The clay contains remains of the present-day temperate bivalve Corbicula fluminalis and the caddis fly Hydropsyche contubernalis – both inhabiting rivers. The presence of C. fluminalis indicates that the deposit most probably is of Middle Pleistocene age, older than the last interglacial, the Eemian.

Highlights

During the Quaternary period that began 2.58 million years, the climate has alternated between glacial and interglacial conditions
In 2018, the Geological Survey of Denmark and Greenland (GEUS) received samples collected at 3-m intervals from a borehole at 55.695°N, 11.839°E, at the address Ejby Havnevej 101 on Sjælland (Fig. 1)
Shells of the bivalve Corbicula were noted in one of the samples; this species indicates a Middle Pleistocene interglacial age (Meijer & Preece 2000; Bennike et al 2019), and since such occurrences are rare in Denmark, we decided to conduct analyses of macrofossils

Summary

Introduction

During the Quaternary period that began 2.58 million years, the climate has alternated between glacial and interglacial conditions. Shells of the bivalve Corbicula were noted in one of the samples; this species indicates a Middle Pleistocene interglacial age (Meijer & Preece 2000; Bennike et al 2019), and since such occurrences are rare in Denmark, we decided to conduct analyses of macrofossils. This data article puts the new occurrence on record and provides details of the macrofossil analysis of the sample. Drilling stopped at a depth of 147.5 m below the terrain surface

Materials and methods

Results and discussion

Conclusions