A sedimentary record from a deep Quaternary valley in the southern Lillebaelt area, Denmark: Eemian and Early Weichselian lithology and chronology at Mommark

Abstract

Glaister, C. 2006 (May): A sedimentary record from a deep Quaternary valley in the southern Lillebaelt area, Denmark: Eemian and Early Weichselian lithology and chronology at Mommark. Boreas, Vol. 35, pp. 320 Á/331. Oslo. ISSN 0300-9483.A unique sequence of Late Saalian, Eemian and Early Weichselian strata is exposed in a coastal outcrop at Mommark in the western Baltic. The sedimentary facies and faunas reflect palaeoenvironmental changes from an initial freshwater lake followed by marine transgression and interglacial deposition in a palaeo-Baltic sea. The upper part of the Eemian marine record indicates regression followed by lacustrine sedimentation and deposition of Early Weichselian aeolian sediments, which are truncated by an erosional unconformity overlain by a till bed. The lower and middle parts of the sequence have previously been correlated with the European glacial Á/ interglacial stratigraphy on the basis of pollen analysis, while the upper part has been dated for the present study using optically stimulated luminescence (OSL) of samples from the aeolian and glacial deposits. A similar complete glacial Á/interglacial Á/glacial succession has not previously been recorded from this area. The Mommark sequence of conformable strata has been subjected to lateral compression, evidenced by folding and low-angle reverse faults. Seismic records from the adjacent waters in the western Baltic reveal a system of buried Quaternary valleys in the area. It is suggested that the interglacial deposition took place in a basin within one of these valleys and that a slab constituting the Mommark sequence, originating from the margin of a valley, has been glaciotectonically displaced northwestwards to the present location.

Palaeoenvironments of a complete Eemian sequence at Mommark, South Denmark: foraminifera, ostracods and stable isotopes

“…Local zones, established on the basis of foraminifera and ostracods (Mom 1 Á/7), lithological units (after Eiríksson et al 2006), local pollen zones (cf. Gibbard & Glaister 2006) and regional pollen zones (Andersen 1961(Andersen , 1975, are shown on the right-hand side.…”

Early Last Interglacial palaeoenvironments in the western Baltic Sea: benthic foraminiferal stable isotopes and diatom-based sea-surface salinity

“…The environmental development is, furthermore, discussed in relation to previously published results from the western Baltic, including studies of foraminifera and ostracods (Kristensen et al 2000), dinoflagellate cyst assemblages (Head 2007) and molluscs (Nielsen et al 2007) from the Ristinge Klint section, as well as environmental proxies for the almost complete Eemian marine sequence at Mommark (Eirı´ksson et al 2006;Funder & Balic-Zunic 2006;Gibbard & Glaister 2006;Haila et al 2006;). Because of their location close to the Danish Belts ( Fig.…”

Eemian and Weichselian environmental development in the western Baltic area, NW Europe - Introduction

“…Foraminiferal assemblages also point to a restricted environment with relatively deep water and high salinity prevailing until c. 6000 after the beginning of the interglacial. This was followed by a gradual decrease in salinity and a shallowing resulting from isostatic uplift and lowering of the global sea level towards the end of the interglacial, as indicated by the sedimentary parameters, the diatoms and the foraminifera (Eiríksson et al 2006;Haila et al 2006;. The main component of this sea-level fall resulted from global eustasy rather than from local isostasy.…”

“…The record continues as freshwater, presumably lacustrine, deposits into the earliest Weichselian, as documented by ostracods . The succeeding Early Weichselian aeolian deposits have been dated by Optically Stimulated Luminescence (OSL; Eiríksson et al 2006). The entire Eemian Á/Early Weichselian sedimentary sequence is truncated by an erosional unconformity overlain by a Late Weichselian till (Eiríksson et al 2006).…”

“…A system of deep Quaternary valleys has been documented by a reflection seismic study in the area (Eiríksson et al 2006). During a subsequent Late Weichselian ice advance, the entire Eemian and Early Weichselian sediment sequence was presumably moved and deformed as a coherent block to its present position in the Mommark cliff.…”