Sandwich KFC - Ramsgate Road: Geoarchaeological Borehole Evaluation Report
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ROCHESTER RIVERSIDE, MEDWAY – SCHOOL SITE: A WRITTEN SCHEME OF INVESTIGATION FOR AN ARCHAEOLOGICAL EVALUATION Sandwich KFC - Ramsgate Road: Geoarchaeological Borehole Evaluation Report National Grid Reference Number: TR 33422 61986 Site Code: AOC SRR21 AOC Project No: 34271 Date: January 2021 © AOC Archaeology 2017 | i | www.aocarchaeology.com SANDWICH KFC – RAMSGATE ROAD: GEOARCHAEOLOGICAL BOREHOLE EVALUATION REPORT Sandwich KFC - Ramsgate Road: Geoarchaeological Borehole Evaluation Report For: Phil Speechley Speechley Property Consultants 57 Thorpe Park Road Peterborough PE3 6LJ On Behalf of: Caskade Caterers Limited Hello House 144 Seven Sisters Road London N7 7NS National Grid Reference (NGR): TR 33422 61986 AOC Project No: 34271 Prepared by: Virgil Yendell Illustration by: Virgil Yendell Date: 23 November 2020 This document has been prepared in accordance with AOC standard operating procedures. Author: Virgil Yendell Date: 8 January 2021 Approved by: Virgil Yendell Date: Draft/Final Report Stage: Draft Date: www.aocarchaeology.com © AOC Archaeology 2020 | i | www.aocarchaeology.com SANDWICH KFC – RAMSGATE ROAD: GEOARCHAEOLOGICAL BOREHOLE EVALUATION REPORT Table of Contents Illustrations .................................................................................................................................................. iii 1 Introduction ............................................................................................................................................ 5 2 Planning Background and proposed development ................................................................................. 5 3 Geology and Topography ...................................................................................................................... 6 4 Archaeological and Historical Background ............................................................................................. 7 5 Geoarchaeological and Palaeoenvironmental Background .................................................................. 15 6 Aims of the Investigation ...................................................................................................................... 16 7 Methodology ........................................................................................................................................ 18 8 Results ................................................................................................................................................ 20 9 Archaeological and Palaeoenvironmental Potential ............................................................................. 31 10 Conclusions and Recommendations ................................................................................................ 35 11 Bibliography ..................................................................................................................................... 37 Appendix A – Deposit Model Data References ........................................................................................... 50 Appendix B – OASIS Form ......................................................................................................................... 51 © AOC Archaeology 2020 | ii | www.aocarchaeology.com SANDWICH KFC – RAMSGATE ROAD: GEOARCHAEOLOGICAL BOREHOLE EVALUATION REPORT Illustrations Figure 1 Site Location Map ................................................................................................................................ 39 Figure 2 Schematic map of the Wantsum Channel valley and islands ............................................................... 40 Figure 3 Data points and transect locations ....................................................................................................... 41 Figure 4 Transect, northwest to southeast across the site showing the levels and thickness of deposits over the underlying geology in section (extrapolated from deposit records) ..................................................................... 42 Figure 5 Topographic plot of the surface of the below ground solid geology (extrapolated from deposit records), suggesting the form of the ancient land surface at c. 10,000 BC ........................................................................ 43 Figure 6 Thickness plot of the below ground lower alluvium (extrapolated from deposit records), representing deposit survival .................................................................................................................................................. 44 Figure 7 Thickness plot of the below ground fluvial deposits (extrapolated from deposit records), representing deposit survival .................................................................................................................................................. 45 Figure 8 Thickness plot of the below ground organic deposits (extrapolated from deposit records), representing deposit survival .................................................................................................................................................. 46 Figure 9 Thickness plot of the below ground upper alluvium (extrapolated from deposit records), representing deposit survival .................................................................................................................................................. 47 Figure 10 Plan showing areas of archaeological potential (extrapolated from deposit records) .......................... 48 © AOC Archaeology 2020 | iii | www.aocarchaeology.com SANDWICH KFC – RAMSGATE ROAD: GEOARCHAEOLOGICAL BOREHOLE EVALUATION REPORT Non-Technical Summary A geoarchaeological evaluation was undertaken on 24-25th November 2020 at the site of Sandwich KFC Ramsgate Road. The work was undertaken by AOC Archaeology Group for Speechley Property Consultants on behalf of the client, Caskade Caterers Limited. The aims of the evaluation were to assess the impact of development on any surviving archaeological remains within the site. The geoarchaeological evaluation comprised the monitoring of 4 geotechnical boreholes and the drilling of 3 purposive geoarchaeological boreholes to maximum c. 8m bgl, and the extraction and retention of the (windowless) cored samples. Geoarchaeological and geotechnical deposit data can be used to identify areas of archaeological potential by characterising the probable nature and depth of sub-surface deposits. The bedrock is Thanet Sand a stiff fine grained, greenish unit, representing a shallow marine deposit of the mid- Thanetian. It was only recorded in one location on site at -4.21m OD, due to the poor retrieval of sediments at depth. The lower alluvium, a pale blue silty clay was recovered below c. -2.97m OD, again in only one location on site. This unit may be related to low-lying peri-marine/ estuarine clays found elsewhere in the Wantsum Channel. Running sands were encountered from c. 0m OD downwards and are thought to be Mesolithic peri- marine to fluvial sands, although recovery of this unit was particularly bad. No organic deposits are recorded on the site. Upper alluvium in the form of variable clays, silts and sands; greenish yellow to blue grey in colour; were recorded from c. 3.37 down to -0.49m OD and likely represent further (late prehistoric to historic) mudflats and saltmarsh expansion. Development impacts from the currently proposed raft foundation will be minimal but may affect the top of the upper alluvium. Although it is difficult to ascertain with certainty the potential of the deposits to contain archaeological remains, the nature of the deposits observed suggests any archaeological remains will be rare and associated with localised late prehistoric to historic mudflat/floodplain exploitation (i.e., brushwood trackways and platforms, fish traps, log boats etc) or historic reclamation i.e., ditches and dykes etc). The impact on these prehistoric deposits could be adequately mitigated by a programme of controlled archaeological watching brief. It is recommended that the impact on deposits considered of moderate palaeoenvironmental potential may be mitigated by further off-site assessment work undertaken on the core samples retained from the evaluation. However, the samples represent incomplete sequences – and due to the poor recovery and loose nature of the lower deposits the sediment within the samples – cannot be reliable considered undisturbed. It is also unlikely further onsite sampling will improve the recovery or nature of future samples. Therefore, any assessment work undertaken on the current samples should focus on the upper portion of the sequence where recovery was more consistent. Even so such work would be on an incomplete sequence of limited chronology. The appropriate mitigation strategy for the site will be decided by and agreed with the Local Authority and their archaeological advisors. © AOC Archaeology 2020 | iv | www.aocarchaeology.com 1 Introduction 1.1 This document details the results of a geoarchaeological borehole evaluation at the site of Sandwich KFC Ramsgate Road (NGR: TR 33422 61986, Figure 1). This WSI has been commissioned from AOC by Speechley Property Consultants on behalf of the client, Caskade Caterers Limited. 1.2 The proposed development site (henceforth “the Site”) is a roughly triangular plot of unused land, bounded to the east by the A256, Ramsgate Road, and further east is the Sandwich and Pegwell nature reserve and the River Stour. The northern boundary of the Site is defined by Richborough Service