Spatial and Chronological Prehistoric Landscape Reconstruction Using Geo-Archaeological Methods in the Lower Scheldt Floodplain (NW Belgium)
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Promotor Prof. dr. Philippe Crombé Vakgroep Archeologie Copromotor Prof. dr. Marc Van Meirvenne Vakgroep Bodembeheer Dr. Tine Missiaen Vakgroep Geologie & Bodemkunde Decaan Prof. dr. Marc Boone Rector Prof. dr. Anne De Paepe Kaftinformatie: Schuine luchtfoto van Doelpolder Noord door Wim De Clercq (Vakgroep Archeologie, UGent) Alle rechten voorbehouden. Niets uit deze uitgave mag worden verveelvoudigd, opgeslagen in een geautomatiseerd gegevensbestand, of openbaar gemaakt, in enige vorm of op enige wijze, hetzij elektronisch, mechanisch, door fotokopieën, opnamen, of enige andere manier, zonder voorafgaande toestemming van de uitgever. Faculteit Letteren & Wijsbegeerte Jeroen Verhegge Spatial and chronological prehistoric landscape reconstruction using geo-archaeological methods in the Lower Scheldt floodplain (NW Belgium) Proefschrift voorgelegd tot het behalen van de graad van Doctor in de Archeologie 2015 Acknowledgements This phd would not have been possible without help of various people and instutions. First of all, I would like to thank the promotor of this doctoral dissertation, Prof. Dr. Philippe Crombé, for giving me the opportunity to study the subject of the prehistoric landscapes of the lower Scheldt floodplain. His expertise, guidance and support have been indispensable in more ways than describable. Furthermore I thank the co-promotors of this doctoral dissertation, Prof. Dr. Marc Van Meirvenne and Dr. Tine Missiaen for their valuable support. I also owe many thanks all (former) colleagues at the department of archaeology- prehistory research group (specifically Dr. Erick Robinson, Dr. Joris Sergant, Machteld Bats and Evy Van Cauteren) and other department members; at the department of soil management-Orbit research group (specifically Dr. Philippe De Smedt, Dr. Timothy Saey, Samuel Delefortrie, Valentijn Van Parys) and at the department of geology and soil science, marine geology research group (specifically Koen De Rycker, dr. Katrien Heir- man, Wim Versteeg). All staff and students involved are kindly acknowledged for their assistance with field work. A PhD bursary was provided by Research Foundation – Flanders (FWO) as part of the project entitled: “Archaeological exploration across the land-sea boundary in the Doel- polder Noord area (Westerschelde estuary): impact of sea-level rise on the landscape and human occupation, from the Prehistory to Medieval times” (Grand number G024911N). The CITG of TUDelft is thanked for providing and introducing me to the GEM-2 and Supersting instruments, TNO for the EM31 & 34 instruments. CPTs and Sonic drill Aqualock cores were carried out by SGS. Thanks to Jan Lippens for his constructive sup- port. Selection of the dated macro remains was performed by Hanneke Bosch (ADC) and Luc Allemeersch (GATE). Radiocarbon dating was carried out by the Royal Institute for Cultural Heritage. The Province of Antwerp-Department of Culture-Heritage Service and the City of Antwerp-Department Archaeology are thanked for providing us with im- portant radiocarbon dates. The Flemish Nature and Forest agency, Natuurpunt and all local farmers are thanked for allowing us access to their grounds. The corings from v Chapter 7 were mostly carried out within the framework of a research project funded by the Special Research Fund of Ghent University, entitled “The Flemish wetlands. An ar- chaeological survey of the Scheldt floodplains”. Most fieldwork was done by Machteld Bats in collaboration with numerous colleagues and students from Ghent University, who all are kindly acknowledged. Specific thanks also go to Hannah Brown for proof- reading the manuscript of Chapter 1, to Lauren Tidbury for proofreading the manu- script of Chapter 3 and dr. Erick Robinson for proofreading the manuscript of Chapter 4. Anonymous reviewers of the papers are also kindly acknowledged. Familie en vrienden, bedankt voor jullie steun. Bedankt, Sofie Scheltjens, voor alle onvoorwaardelijke steun, geduld, aanmoedigin- gen en offers van de voorbije jaren. Ik zou dit proefschrift dan ook graag aan haar opdragen. vi Preface This PhD dissertation is written in the context of an interdisciplinary FWO project (Grand number G024911N), entitled ‘Archaeological exploration across the land-sea boundary in the Doelpolder Noord area (Westerschelde estuary): the impact of sea-level rise on the landscape and human occupation from the prehistory to medieval times’ and supervised by Prof. Dr. M. De Batist (Ghent University), Prof. Dr. Ph. Crombé (Ghent University), Prof. Dr. J. Verniers (Ghent University) and Prof. Dr. T. Soens (University of Antwerp). The project investigates the transition between the present onshore and off- shore coast in the Scheldt polders of NW Belgium, more specifically at the location of Doelpolder-Noord (Figure 1). Reconstructing the gradual drowning of the landscape and its effects on human occupation through time, starting from the earliest prehistory, was the principal aim of this project. Given the constant threat of destruction caused by the development of the Antwerp harbor, a survey strategy had to be developed allowing detailed and fast (geo-)archaeological assessment. This methodology should be applica- ble to other similar coastal areas in Belgium and abroad. The tasks and responsibilities of the archaeological partners of this project, namely Prof. Dr. Philippe Crombé and myself, were archaeological drilling, analysis of archaeo- logical finds, Ground Penetrating Radar (later replaced with electromagnetic induction survey and electrical resistance imaging), Cone Penetration Testing (via subcontract), 14C dating (via subcontract) and landscape occupation modelling and reconstruction. This PhD dissertation is a result of the fulfilment of these responsibilities, with a major focus on the supratidal zone of the land-sea transition. Fieldwork was challenged by accessibility issues of the nature reserve of Doelpolder- Noord, because it was specifically designed for bird nesting. As a result, the main ‘field laboratory’ of the project was only accessible in July and August. The impact on the en- vironment of the selected methods had to be minimized as well. Nearby fields were not suitable as test survey areas because access was denied by farmers, who are threatened by the expansion of the harbor and weary towards researchers, despite argumentation and illustration of the non-invasiveness of near surface geophysical methods. vii Nevertheless, some pastures could be surveyed aside from Doelpolder-Noord using a Dualem 421s sensor. These surveys are not included in this dissertation, because the results did not reveal prehistoric landscape features but rather badly drained (Post-) Medieval gullies and indications of brackish groundwater. Due to the restricted accessibility in the Scheldt polders, Kerkhove Stuw was selected as an additional test site along the Middle Scheldt. Here, a prehistoric natural levee had already been mapped by gridded coring, providing excellent validation data. After ERI and EMI survey, however, it became clear that recent land raising with construction waste and asymmetric drainage of the levee due to water extraction impacted near sur- face geophysical results negatively. Therefore, only the CPT results were analyzed, pub- lished and included in this PhD (Chapter 3). Finally, a large paleolandscape coring survey of circa 60 ha in a developer-led archae- ological project at Verrebroek Schoorhavenweg prompted a third test-case. Here, circa 20 ha was selected for a Dualem21s survey. The results revealed a shallow prehistoric paleotopography, which was also recorded in gridded coring data. Furthermore, land division structures in two orientations were discovered. During development-led trial trenching at regular spacing, the archaeological contractor, namely GATE Archaeology bvba, kindly allowed small trial trenches to be dug targeted towards the geophysical results. The excavation results indicate that aside from the prehistoric landscape, two different phases of (late) medieval land division structuring were at least partly record- ed in both Dualem 21s EMI survey. The targeted trial trenches proved to add vital inter- pretative information to the geophysical survey results. The preliminary results were included in the archaeological report of the archaeological contractor. Full publication awaits dating and paleo-ecological analysis and will be done in the future. Therefore this survey was not included in this PhD dissertation. The papers in this PhD were often a multidisciplinary team effort. Although I deliv- ered large contributions in most chapters, specific parts of them rely heavily on the co- authors. Most markedly, the seismic survey data in Chapter 1 were processed and inter- preted by Dr. Tine Missiaen (Ghent University). Electromagnetic induction-, electrical resistance-, cone penetration testing- and archaeological coring results were largely my work. Tine Missiaen also processed and interpreted the CPT-U and CPT-S data of Chap- ter 3, while CPT-E analysis and subsurface modelling was done by myself. Chapter 4 was mostly my work. The paleo-ecological and archaeological interpretations in Chapter 5 would not have been possible without the help of respectively Dr. Koen Deforce (Royal Belgian Institute of Natural Sciences) and Prof. Dr. Philippe Crombé, while chronological Bayesian modelling was my main part of this paper. Chapter 6 is mostly my work. The EMI depth modelling routine was developed and applied by Dr. Timothy Saey (Ghent University). Chapter 7 is based on