Ian Panter

A critical review of hydrological data collection for assessing preservation risk for urban waterlogged archaeology: A case study from the City of York, UK

Environmental change caused by urban development, possibly augmented by climate change, may result in accelerated decay of in situ archaeological resources. Damage may be related to changes in hydrological processes. Such archaeological resources have to be considered in environmental planning. In this paper we highlight the need for improved hydrological data from urban archaeological sites using the case study of the City of York, UK, arguably one of the most well studied and well preserved urban archaeological environments globally. We suggest that the quality of hydrological data collected during routine surveys and experimental work must be improved and standardised in order for us to produce reliable archaeological risk models for urban sites.

Reburial in the context of development: Approaches to reburial in the English planning process

Abstract Rescue archaeology in England is now firmly embedded in the planning process, following the introduction by the UK government of Planning Policy Guidance Note 16 in 1990 (PPG 16; Departmentof the Environment. Planning Policy Guidance Note 16 — Archaeology and Planning. HMSO, London (1990)). The basic premise of PPG 16 is a strong preference for in situ preservation of nationally important archaeological remains. This often includes reburial of archaeology prior to construction activity, once it has been exposed in test-pitting (‘evaluations’) or full excavation. Reburial strategies are often prepared by civil engineers and there appears to be an overemphasis on consideration of the potential physical impacts on the archaeology. These strategies usually include the use of geotextiles and sand, or other graded material, chosen for its particular particle size/shape characteristics. A greater awareness of the chemical and physical characteristics of a burial environment is now required to ensure that reburial is effective. Archaeologists and conservators are beginning to consider both the natural and, increasingly, the ‘man-made’ (industrial, domestic and agricultural) changes to the soil chemistry of an archaeological site. More use needs to be made of the potential information ‘locked up’ in the artefactual material retrieved from evaluations and excavation nearby. An assessment of the degree of preservation of material should be an integral component for the design of a reburial strategy.

Is Preservation In Situ an Unacceptable Option for Development Control? Can Monitoring Prove the Continued Preservation of Waterlogged Deposits?

Abstract This paper will outline the approach taken for monitoring of two waterlogged areas in England: the multi-period deposits beneath the historic town of Nantwich, Cheshire, and the Bronze Age timber platform at Whittlesey, Cambridgeshire. These two examples allow contrast and comparison between urban and rural contexts, and between multiple ownerships and single development. The projects also illustrate how English planning guidance can be variously interpreted dependent on conflicting aims and objectives. The paper will describe the characteristics of the sites, their past history and present threats, and the suggested management strategies for each. The duration, spatial interval, and methods of monitoring (including use of in situ redox probes, Time Domain Reflectometry, sediment geochemistry, and water-level measurement) will be discussed, and how short-term data-gathering is actually what influences decision-making.

Planning policy, in situ preservation and wetland archaeology in the UK: a response

INTRODUCTION Recent debate has questioned the viability of a number of current approaches to the wetland archaeological record, from both the legislative and methodological perspectives [1]. This debate, whilst timely, is somewhat ill-judged in its scope and approach. The following offers an overview of current initiatives aimed at enhancing our understanding of waterlogged burial environments and assesses the viability of hydrological and biochemical monitoring approaches, which have been directly questioned. The conclusions drawn are that whilst reflective practice is essential in any discipline, Gearey and Chapman’s critique of in situ preservation is perhaps premature, at best. Future mitigation will be led from the perspective of in situ preservation as the preferred option for significant archaeological remains. As such we clearly need to further refine the lessons learnt to date, to ensure that sustainable longterm mitigation strategies are developed. At the fundamental level of enquiry, there are numerous recent research initiatives aimed at developing our understanding of the wetland archaeological record, in situ preservation and degradation [e.g. 2 and 3], and ongoing research funded (in part) by English Heritage is currently being undertaken by the first author. This research aims to aid archaeologists in characterizing burial environments, understanding long-term approaches to in situ monitoring [4] and assessing the impacts of de-watering and the monitoring and evaluation of changes in specific burial environments. Obviously, understanding hydrological fluctuations and their impact on the buried resource is difficult [1] and in situ preservation may indeed be an archaeological nirvana [5]. When considering Planning Policy Guidance note 16 (PPG16) [6], Gearey and Chapman [1] highlight concerns regarding the lack of distinction between different types of sites and deposits, and the reliance on county archaeologists to make decisions for appropriate mitigation, arguing that current procedure is inadequate [7]. It is clearly impossible for any guidance note to adequately ‘account for the specific circumstances of the range of threats to many wetland archaeological sites’ [7]. This is especially so when, globally, the myriad of site-specific parameters relating to the burial environment (immediate artefact environment, soils and sediments, chemical composition, etc.), the object or site (composition, decay status prior to burial, etc.), the hydrological regime (inputs/outputs, etc.) and any/all influences upon these cannot currently be quantified. Additionally, as per PPG16, preservation in situ whilst desirable, also has to be feasible, and without a solid understanding of the hydrology of a site over the longer term any attempts at in situ preservation will be flawed. Finally, the viability of hydrological and biochemical monitoring has been questioned [7]. This paper will present some initial observations from the mediumterm monitoring of an archaeological site in an urban context that has been monitored since September 2001, and which is currently still being studied (i.e. it has been studied for the past three and a half years). Other studies [8–10] have undertaken monitoring of varying durations and monitoring intervals. However, these have seldom matched the duration of study seen on the continent [11–13], where monitoring of urban deposits has been undertaken since 2001 at Bryggen in Bergen (continual monitoring is planned for the next twenty

Deterioration of the Hanson Logboat: chemical and imaging assessment with removal of polyethylene glycol conserving agent

The state of preservation of wood in two samples from the Hanson Logboat, currently on display in Derby Museum and Art Gallery, was analysed using elemental analysis (EA), pyrolysis–gas chromatography/flame ionisation detection (Py-GC/FID), pyrolysis–gas chromatography/mass spectrometry (Py–GC/MS) and scanning electron microscopy (SEM). The samples were collected in 2003, after the boat had undergone conservation, and in 2011 after the condition of the boat began to deteriorate. Solvent extraction enabled removal of polyethylene glycol, with which the wood had been impregnated during conservation, allowing the degradation of the cellulose and lignin polymeric components of the woods to be assessed. Elemental compositions (C, H, N, O, S), Py–GC/FID, Py-GC/MS and SEM imaging reveal extensive degradation of the wood polymers during the eight year period since conservation.

How to Carefully Construct a Hospital over a Roman Boat in Central London, UK

This paper examines the Roman boat, buried beneath Guys Hospital in London, UK. A small part was discovered in 1958, and has been carefully left free of disturbance since that date. In 2009, a proposal was made to construct a 14-storey building above the boat; clearly raising challenges for preservation, not to mention the philosophy of burying or excavating and entire ancient monument. A trial pit was opened to see if any remains of the boat survived and uncovered well-preserved timber planks and nails preserved five metres below ground level. Consequently, archaeologists worked closely with the entire design team, determined that more was required than the usual scheme of preserving and monitoring the boat. A legal agreement was secured, making this one of the few projects in the world to have a clearly structured and enforceable plan, if the monitoring data show demonstrable deterioration.

Pewter Funerary Chalices and Patens from York Minster

IT HAS BEEN accepted for many years that, unlike their silver counterparts, pewter chalices and patens found in priestly burials continued largely unchanged in form throughout the medieval period; this means that the presence of a pewter chalice or paten does not in itself currently offer any reliable dating of a related burial beyond a broad 13th–16th-century timeframe. Pewter chalices and patens recovered from 25 burials within York Minster between 1966 and 1973 are thought to represent the largest collection found within one church in England, and initial assessment of this collection and its related excavation data indicated that it offered the possibility of providing findspots for some of the vessels from recorded burials or dated archaeological sequences, and thus to provide more examples of tightly drawn dating. In the event, it has been possible to assign a single chalice and paten set to a recorded individual, and to provide others with periods within which, or after which, burial occurred. Scrutiny of the objects also resulted in the identification of two distinct forms of paten, one of which was shown in seven instances to bear incised motifs which had not been noted or commented upon previously.

Lessons from Star Carr on the vulnerability of organic archaeological remains to environmental change.

Significance Wetland deposits provide a unique repository of archaeological and environmental information, preserving organic remains rarely found elsewhere. Star Carr is an impressive example, having provided unique evidence for human interactions with the landscape at the end of the last ice age. Tragically, here we provide experimental evidence that human modifications of the local environment are leading to changes in the site’s geochemistry, resulting in the rapid loss of bone and wood artifacts. Our research demands a reassessment of the assumption that sites such as Star Carr should be preserved in situ for the benefit of future researchers and demonstrates that potential changes to the burial environment must be considered before such a policy is pursued. Examples of wetland deposits can be found across the globe and are known for preserving organic archaeological and environmental remains that are vitally important to our understanding of past human–environment interactions. The Mesolithic site of Star Carr (Yorkshire, United Kingdom) represents one of the most influential archives of human response to the changing climate at the end of the last glacial in Northern Europe. A hallmark of the site since its discovery in 1948 has been the exceptional preservation of its organic remains. Disturbingly, recent excavations have suggested that the geochemistry of the site is no longer conducive to such remarkable survival of organic archaeological and environmental materials. Microcosm (laboratory-based) burial experiments have been undertaken, alongside analysis of artifacts excavated from the site, to assess the effect of these geochemical changes on the remaining archaeological material. By applying a suite of macroscopic and molecular analyses, we demonstrate that the geochemical changes at Star Carr are contributing to the inexorable and rapid loss of valuable archaeological and paleoenvironmental information. Our findings have global implications for other wetland sites, particularly archaeological sites preserved in situ.

Monitoring and Management Options in the Preservation of Urban Waterlogged Deposits, Nantwich, UK

A baseline survey in 2007 characterized the physical and chemical conditions for preservation within waterlogged remains at Nantwich. Installation of eighteen dipwells has allowed a five-year monitoring programme to be conducted from 2011. Two add-on projects supplemented this monitoring programme by examining the different methods for redox measurement, and for soil moisture measurement using Time Domain Reflectometry (TDR). Initial results show two main zones of preservation, with reducing conditions attributed to location of the deposits in the floodplain, and a second zone uphill with more variable conditions for preservation. This study shows that sediment-coring programmes combined with dipwell installations can provide useful data to assess and monitor in situ preservation conditions, which can help to formulate management strategies for conservation of waterlogged archaeological deposits. This paper focuses on the efficacy of the methodology, referencing in particular comparative monitoring techniques and lists a series of recommendations for future studies.