Diatomeeën als ecologische indicatoren in de Vlaamse archeologie : Romeins en middeleeuws Oudenburg (prov. West-Vlaanderen)

Door de studie van bepaalde vondstcategorieën van organisch materiaal uit archeologische contexten is het deels mogelijk landschap en vegetatie rond vroegere menselijke woonplaatsen te reconstrueren. Dergelijke ecologische reconstructies zijn met name interessant voor sites die een lange bewoning gekend hebben maar die in een duidelijk veranderende omgeving gelegen zijn. Oudenburg in de provincie West-Vlaanderen is daar een voorbeeld van. Het dorp bevindt zich geografisch op de overgang van de kustvlakte en de zandstreek, wat naast een hellingsgradiënt ook een overgang van klei- naar zandbodem inhoudt. Vooral de kustvlakte kende in de loop van de laatste millennia grote landschapswijzigingen onder invloed van de wisselende inwerking van de zee, traditioneel beschreven in een model van transgressie- en regressiefasen. Deze fenomenen worden steeds beter beschreven door recent geologisch onderzoek, wat een kader biedt voor huidige ecologische reconstructies

Het archeologisch onderzoek in Raversijde (Oostende) in de periode 1992-2005

Raversijde - sinds 1970 deel van de stad Oostende, voordien Middelkerke - gaat terug tot een laatmiddeleeuwse vissersnederzetting met de naam Walraversijde. Deze vissersnederzetting was gesitueerd nabij de huidige grens Middelkerke/Oostende in een zone die zich grotendeels binnen het huidige provinciedomein Raversijde bevindt, maar zich ook nog in belangrijke mate uitstrekt tot op het strand ter hoogte van dit domein.In deze publicatie over archeologisch onderzoek in Raversijde komen de opgravingscampagnes op het grondgebied van het provinciedomein Raversijde uit de periode 1992-1998 uitvoerig aan bod. Daarnaast worden een aantal markante opgravingsresultaten van na 1998 belicht: het muntdepot dat op het einde van 1999 werd aangetroffen, de in 2003 aangesneden zone met begravingen en de in 2005 geïdentificeerde Romeinse dijk.Dit 8ste deel van de Relicta Monografieën behandelt chronologisch de resten en sporen uit de prehistorie, de Romeinse periode, de late middeleeuwen en de vroeg-moderne tijden. Deze publicatie is in de eerste plaats een opgravingsverslag: ze beschrijft, analyseert en interpreteert de belangrijkste sporen samen met een selectie van de aangetroffen mobiele resten en de resultaten van natuurwetenschappelijk onderzoek

The younger Dryas and Preboreal landscape in the Moervaart area (northwestern Belgium) and the apparent decrease in human occupation

This paper presents the results of multi-disciplinary research carried out on the deposits of a residual channel (“Peerdemeers”) of the Kale/Durme River in the Moervaart depression, NW Belgium. The combination of physical, botanical, zoological and chemical analyses allowed a detailed reconstruction of the channel ecosystem and the vegetation in the surrounding landscape during the Younger Dryas and Early Holocene. A chronology for the record was provided by radiocarbon dating. Vegetation patterns were influenced by major climate changes that occurred during this period. During the early Younger Dryas, the river channel was active and vegetation was open with scattered birch copses, shrubs, grasses and herbs. The channel was cut-off in the late Younger Dryas, while some heath developed in the area. The Friesland Phase is characterised by a lithological change and increase in water level in the residual channel. Dwarf birch disappeared and boreal forests developed. The area however, remained relatively open compared to other coversand areas in NW Europe. The Rammelbeek Phase is considered as a drier, more continental climate phase in which forest expansion was temporarily interrupted and grasslands became more abundant. Also at the “Peerdemeers” site an increase in grasses is recorded. During the entire period (ca. 1,000 years) there is no hard evidence for human activity. The absence of archaeological evidence is in sharp contrast with the preceding (Allerød) and succeeding periods (Boreal). This suggests that environmental conditions during the YD and PB were probably too unfavourable for hunter-gatherers to remain in the Moervaart area

Weichselian Lateglacial environmental and vegetation development in the Moervaart palaeolake area (NW Belgium) : implications for former human occupation patterns

In this paper, a detailed vegetation and environmental reconstruction for the Lateglacial interstadial in the Moervaart area (NW Belgium) is discussed, in relation to former human occupation patterns. This reconstruction is based on a multi-disciplinary research carried out on calcareous deposits of a large palaeolake (~ 25 km2). The combination of physical (magnetic susceptibility, micromorphology, organic matter, calcium carbonate), botanical (pollen, macrofossils, diatoms), zoological (chironomids, molluscs, ostracods) and chemical analyses (stable carbon and oxygen isotopes) allowed for a highly detailed reconstruction of the lake ecosystem and vegetation surrounding the lake. The chronology of the lake record was provided by radiocarbon dating and comparison with the nearby Rieme sites and regional biostratigraphy. During the Bølling phase, the Moervaart palaeolake formed as result of a major rise of the groundwater table in the area. Water level rise continued during the early Allerød phase and a rich water flora and fauna developed in the lake. From this period onwards, the area provided a suitable landscape for the Federmesser Culture hunter–gatherers with fresh drinking water, extensive and fertile woodlands and lake edges for wild game hunting, plant gathering and fowling. Water levels rose to a maximum at the end of the early Allerød. Thereafter, an outlet for the lake was formed in the east. As a result, water levels gradually decreased during the middle to late Allerød and eventually the Moervaart lake turned into a swamp and ceased to exist. In combination with the prevailing colder conditions, this led to a marked population decrease with probably temporary abandonment of the region

Hunter-gatherer responses to the changing environment of the Moervaart palaeolake (Nw Belgium) during the Late Glacial and Early Holocene

This paper presents new geo-archaeological perspectives on the Late Glacial and Early Holocene human occupation around a large palaeolake, the Moervaart palaeolake (∼25 km2). Intensive fieldwork, using invasive and non-invasive survey techniques, combined with modelling of the palaeotopography and palaeogroundwater and multi-proxy palaeoecological analyses have resulted in a detailed reconstruction of the landscape during the Final Palaeolithic and Early Mesolithic occupation of the area. A major shift in the occupation from the Federmesser Culture to the Early Mesolithic was contemporaneous with a sudden and drastic change in the palaeohydrology of the area between ca. 13,300 and 13,000 cal BP (end of Allerød), which coincided with a short but abrupt cooling event known as the Intra Allerød Cold Period (IACP) GI 1b. It is assumed that this event triggered the sudden drying up of the Moervaart palaeolake and surrounding ponds, which until then had provided Federmesser hunter-gatherers with extensive and fertile grounds for hunting, gathering and drinking water. The population decline which followed this hydrological event was reinforced by the prevailing cold and harsh conditions of the Younger Dryas and probably lasted until the Pre-boreal. Hunter-gatherers returned to the area in the Boreal, now settling along the proximal floodplain regions of a meandering channel which was connected with the southern Scheldt River

Multiple oscillations during the Lateglacial as recorded in a multi-proxy, high-resolution record of the Moervaart palaeolake (NW Belgium)

This paper presents the results of multi-disciplinary research carried out on the deposits of Moervaart depression, NW Belgium, one of the largest palaeolakes (∼25 km2) that existed during the Lateglacial interstadial in NW Europe. The multi-proxy study, including physical (organic matter and calcium carbonate, magnetic susceptibility, micromorphological), botanical (pollen, macrofossils, diatoms), zoological (ostracods, molluscs, chironomids) and chemical analyses (stable carbon and oxygen isotopes) has resulted in a detailed reconstruction of the Lateglacial landscape as well of the local conditions that prevailed in the lake itself. A chronology of the record was provided by radiocarbon dating and comparison with radiocarbon dates of the nearby Rieme site. These yielded a good match with the regional biostratigraphy. During the Lateglacial, vegetation and geomorphology of the landscape in general changed from a tundra landscape to a boreal forest. The vegetation development, however, was interrupted by a number of cold reversals. Three centennial-scale cold oscillations are present in the record: 1) the so-called Older Dryas corresponding to GI-1d in the Greenland ice-cores, 2) a short and pronounced cold event during the early Allerød, which could be correlated to GI-1c2 and 3) a cooling event during the late Allerød probably corresponding to the Intra Allerød Cold Period (IACP) or GI-1b. The latter most likely was responsible for the disappearance of the Moervaart palaeolake