Late Quaternary (15 ka to present) development of a sandy landscape in the Mol area, Campine region, north-east Belgium (original) (raw)
Related papers
The geomorphological analysis of two sections cut into a sandy landscape in north-east Belgium enabled the establishment of a chronology for a sequence of events during the last 15 ka that illustrate the polycyclical nature of the evolution of such landscapes. Field descriptions, analytical sediment and soil characterization, and pollen analysis are combined with the optically stimulated luminescence dating method to unravel the recent geomorphological history of the investigated site. The principal results include apparently discontinuous sand deposition between 15and12ka,landscapestabilizationandPodzolformationbetween15 and 12 ka, landscape stabilization and Podzol formation between 15and12ka,landscapestabilizationandPodzolformationbetween12 and 1 ka, the development of a drift sand landscape between $650 and 200 a, and renewed stabilization over the last two centuries. The results are discussed in the light of climate, land-use and vegetation changes and compared with findings at similar sites in the European Sand Belt.
Boreas, 2013
Robust, dateable sources of palaeoenvironmental proxy data are scarce in the southwestern Kalahari Desert, and this study investigates the potential of pan (playa) floor sediments as an archive of late Quaternary environmental change. Augering has revealed the presence of up to 3 m of clay-and silt-rich deposits in the base of Witpan, a small pan basin set amongst linear and lunette dunes. The weakly-stratified deposits include aeolian quartz sands and evaporites amongst a clay-rich groundmass, and are believed to have accumulated on a wetter-than-present pan surface. The aeolian quartz fraction has been dated with Optically Stimulated Luminescence (OSL), and reveals accumulation of at least 50 cm of sediment at around 20 ka, and previous accumulation at around 32 ka. The northern and southern sections of the pan are shown to maintain some hydrological independence, attributed to bedrock outcropping, and also show distinct differences in their physical sedimentology. Biogenic proxies are poorly preserved, with neither diatoms nor pollen found in adequate quantities, although phytoliths, found in both the pan-floor sediments and the fringing lunette dune, may offer a more resilient palaeoenvironmental indicator. The possible value of pan floor sediments as dryland archives of physical and chemical, and possibly selected biogenic, palaeoenvironmental proxies, combined with OSL-constrained chronologies, should not be discounted.
Geologica Belgica
In Belgian lithostratigraphy, the Gent Formation was previously introduced to encompass all Quaternary sandy aeolian sediments. It has been difficult to apply, however, as it was incomplete, regionally biased, and not based on sediment properties alone. To solve this problem the Gent Formation is revised both in terms of definition and subdivision. Morphological and chronological criteria were omitted to allow ranking strata on the basis of visible lithological properties. The Belgian sand belt is newly introduced to designate the area where these sediments were deposited. The Gent Formation is subdivided into five members based on distinct lithological properties, and as a consequence reflecting different palaeoenvironmental conditions during deposition. Whenever feasible, each member is put in a chronostratigraphical and geomorphical context. The new subdivision is discussed and compared with earlier Belgian lithostratigraphical frameworks, as well as to the most recent one for comparable deposits in the Netherlands.
OSL dating of an inland dune along the lower River Scheldt near Aard (East Flanders, Belgium)
Netherlands Journal of Geosciences - Geologie en Mijnbouw, 2011
The chronostratigraphic position of aeolian dunes in East Flanders (Belgium) has been under debate for decades. Until now, the only available age information consisted of a limited number of radiocarbon dates, which provided indirect sediment deposition chronologies. This paper reports on the first direct determination, by quartz-based single-aliquot optically stimulated luminescence dating, of the time that dune sands were deposited along the Lower River Scheldt in Belgium. The sediments are dated at 12.0±0.9 ka (n = 5), which confirms that the time of inland dune formation in East Flanders dates from the Younger Dryas period and should not be constrained to the Holocene.
A medieval settlement caught in the sand: Optical dating of sand-drifting at Pulle (N Belgium
Quaternary Geochronology, 2010
Close to the village of Pulle (N Belgium), six trenches were opened for archaeological research. This resulted in the discovery of a dense spread of traces of human settlement. Only a relatively small number of artefacts was found, but these allowed attributing the traces to habitation during the Iron Age and Early Middle Ages. In one of the trenches, the level with the archaeological finds was covered by a driftsand dune. The accumulation of these aeolian sediments presumably put an end to the human occupation. Hence, dating these sediments might provide essential information as to the chronology of the occupational history of the site. Quartz-based optical dating was applied to constrain the timing of sand-drifting at Pulle. All samples showed satisfactory luminescence characteristics and yielded an internally consistent set of optical ages. Within analytical uncertainty, the age results show no increase with depth and do not allow differentiating between distinct phases of sand-drifting. An average age of 1.2 AE 0.1 ka was obtained, which is interpreted as an upper age limit for human occupation at the site. The results also illustrate (the limit on) the time resolution that can be achieved through conventional quartz single-aliquot optical dating techniques; considering these limitations, we conclude that the sand-drifting at Pulle occurred during a single, fairly short event in the Early Middle Ages.
2012
Based on radiocarbon and optically stimulated luminescence (OSL) results obtained in the last 5 yr, this paper discusses the absolute chronology of the formation of one of the largest sand dunes within NW Belgium, the Great Ridge of Maldegem-Stekene. Multiproxy analysis of 6 sedimentary sequences points to a complex formation history covering the entire Late Glacial. Dry phases, characterized by eolian deflation and sedimentation, alternated with wet phases in which numerous mostly shallow dune slacks were filled with freshwater. The latter reached their highest water level during the first half of the Allerød, attracting both animals (e.g. European elk) and humans (Federmesser hunter-gatherers). Near the end of the Allerød, all dune slacks finally disappeared as they were filled in with windblown sand ("coversand"), likely forcing prehistoric hunter-gatherers to leave the area.
Geomorphology, 2009
ABSTRACT The Late Glacial dune complex at Opgrimbie (NE Belgium) is thought to represent a complete record of the Late Pleniglacial to Holocene change at the southernmost part of the coversand area. In this work, the chronology of the site was reinvestigated using quartz-based single-aliquot optical dating. Nine samples in total were collected from sediments above and below a bleached horizon, the Opgrimbie layer, which laterally passes into a sandy peat layer; earlier radiometric radiocarbon dating and pollen analyses showed the latter to be of Bølling age (14.8–14.1 ka cal. BP). The sampled sequence is overlain by a second horizon, the Usselo horizon, for which an Allerød age (14.0–13.0 ka cal. BP) was deduced from one radiometric 14C age and palynological evidence. This was confirmed by AMS data obtained as part of this study.All nine quartz samples showed satisfactory luminescence characteristics, and yielded an internally consistent set of optical ages. The dataset contains no clear outliers and the observed variation is not much larger than that expected from uncertainties. The sediments over- and underlying the lowermost bleached horizon are dated at 12.9 ± 0.9 ka (n = 6) and 13.0 ± 0.8 ka (n = 3), respectively. These ages do not confirm the Bølling age that was previously established for this horizon; the optical ages are, however, consistent with the chronostratigraphical position of the sediments below the Usselo soil of Allerød age. As such, the OSL ages question if the Lateglacial aeolian succession is fully developed at Opgrimbie, and they challenge its significance as a type locality.
Radiocarbon
Based on radiocarbon and optically stimulated luminescence (OSL) results obtained in the last 5 yr, this paper discusses the absolute chronology of the formation of one of the largest sand dunes within NW Belgium, the Great Ridge of Maldegem-Stekene. Multiproxy analysis of 6 sedimentary sequences points to a complex formation history covering the entire Late Glacial. Dry phases, characterized by eolian deflation and sedimentation, alternated with wet phases in which numerous mostly shallow dune slacks were filled with freshwater. The latter reached their highest water level during the first half of the Allerød, attracting both animals (e.g. European elk) and humans (Federmesser hunter-gatherers). Near the end of the Allerød, all dune slacks finally disappeared as they were filled in with windblown sand ("coversand"), likely forcing prehistoric hunter-gatherers to leave the area.