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.
We present a high-resolution palaeoenvironmental reconstruction covering the late Holocene from the Skagerrak and other sites in the North Sea area. The data, which are based on the analyses of marine sediment cores, reveal a marked environmental shift that took place between AD 700 and AD 1100, with the most pronounced changes occurring at AD 900. Both surface and bottom waters in the Skagerrak were subject to major circulation and productivity changes at this time due to an enhanced advection of Atlantic waters to the North Sea marking the beginning of the 'Mediaeval Warm Period' (MWP). The observed increase in bottom current strength is especially remarkable as there is hardly any comparable signal in the older part of the record going back to 1000 BC. At the transition to the 'Little Ice Age' (LIA) the bottom current strength remains at a high level, now probably forced by atmospheric circulation. Thus, despite opposite temperature forcing, these two consecutive climate scenarios are apparently able to generate distinctly stronger bottom currents in the Skagerrak than observed in the preceding 2000 years, and demonstrate the significance of climatic forcing in shaping the marine environment. Indeed, both the MWP and the LIA are reported as strong climatic signals in northwest Europe, being the warmest (except the late twentieth century) and coldest periods, respectively, during at least the last 2000 years.
Studies of marine records from the northwestern European shelf and the northern North Atlantic suggest that last interglacial environments were less stable in this area than in the mid-latitude Atlantic. The influx of Atlantic water masses to the northern North Atlantic was generally higher, and the meridional temperature gradient was steeper, during the last interglaciation than during the Holocene. Strong north-south sea-surface-temperature gradients during the early Weichselian indicate a generally low influx of Atlantic water to the northern North Atlantic, even during interstades. C 2002 University of Washington.
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