Climate Change, Stone Surface Modification and Subsurface Response: Complex Behaviour of Historic Sandstone in response to Shifting Climatic Trends
Historic Scotland ‘Heritage Science’ Fellowship (March 2012 – February 2013)
Recent research carried out within the School of GAP has proposed that environmental controls on stone decay processes could change significantly in response to projected climate change. Summer dryness and winter wetness are both set to increase, the latter linked to projected precipitation increases in autumn and spring months. If so, this could increase the time that stone structures remain wet and also the depth of moisture penetration – building stone in Northern Ireland has already responded to this by an increased incidence of algal ‘greening’.
Current and projected climatic trends have aesthetic, physical and chemical implications that are not currently built into our models of sandstone decay, especially with respect to the role played by deep-seated wetness on sandstone deterioration and decay progression and the feedbacks associated with, for example surface modification by algal growth. In particular it is proposed that algal biofilms may aid moisture retention and further facilitate moisture and dissolved salt penetration to depth (though this is, as yet, largely untested). Thus, whilst the outer surface of stone may continue to experience frequent wetting and drying associated with individual precipitation events, the latter is less likely to be complete and the interiors of building blocks may in fact only experience wetting/drying in response to seasonal cycling. A possible consequence of deeper salt penetration could be a delay in the onset of surface deterioration, but more rapid and effective retreat once it commences as decay mechanisms ‘tap into a reservoir of deep salt’. Fresh stone has been monitored at the Derrygonnelly stone decay test facility (run by the WRG, QUB, funded by EPSRC), but this initial-stage monitoring has not taken into account how surface modification may impact subsurface patterns of moisture, temperature and salt (in, for example, historic stone), and has not investigated how feedbacks set-up by surface change may alter behaviour.
Many historic sandstones have already undergone surface modification, so this research is specifically targeted at understanding how stone with a long and complex exposure history respond to climate change (in terms of subsurface response).
1. To understand how shifting climatic trends drive surface modification, and how surface modification, in turn, alters subsurface patterns of temperature, moisture and salt distribution (including feedbacks)
2. To produce protocols for managing historic sandstone under wet conditions to prolong service life and value
1. Catalogue historic sandstone buildings and monuments in the NWUK impacted by wetter winters and potentially drier summers (and associated surface modification or decay forms)
2. Continue environmental monitoring of surface and subsurface conditions at Derrygonnelly stone decay test facility – specifically to investigate how surface alteration may set up feedbacks that influence subsurface response (temperature and moisture profiles) – not a consideration in this set-up until now
3. Elucidating the potential synergy of wet winters and damage by de-icing salts
4. Set up laboratory simulation experiments to investigate
i. How changing albedo may influence subsurface temperature response
ii. How deep wetting followed by rapid drying may influence subsurface distribution of salts
iii. How surface decay may alter subsurface patterns of temperature and moisture, and progress while the stone interior is still wet
iv. How surface treatments may alter subsurface response
v. How deeply salts may penetrate by diffusion over a 6-month period (simulating the October to March ‘wet’ period)
5. Develop models of surface modification / subsurface response influenced by climate change, validate simulation results with real-world historic sandstone structures using catalogue complied (objective 1)
6. Work with end-users to develop protocols for management of historic stone under wet winter / dry summer conditions
Yet, despite its appearance in television programmes, book covers, learned articles and so forth, the Gough Map’s origins are uncertain, including who made it, how, where and why? This project seeks to address these questions by using an innovative approach to explore the map’s ‘linguistic geographies’, that is the writing used on the map by the (unknown) scribes who created it. This technique involves specialist palaeographic and linguistic skills that are normally applied to text manuscripts, but with this project they are being tried on a map manuscript, somewhat experimentally, with the aim of not only finding more about the Gough Map’s making but also the transferability of particular methods from linguistic to cartographic history. The project involves a group of researchers from across three UK HEIs, each bringing distinctive skills and expertise to bear. Each has an interest in maps and mapping, though from differing disciplinary perspectives, from geography, cartography and history. Their aim is to learn more about the Gough Map, specifically, but more generally to contribute to ongoing intellectual debates about how maps can be read and interpreted; about how maps are created and disseminated across time and space; and about technologies of collating and representing geographical information in visual, cartographic form.
The project’s focus on a map, as opposed to a conventional written text, will also open up theoretical and conceptual issues about the relationships between ‘image’ and ‘text’ – for maps comprise both – and about maps as objects and artifacts with a complex and complicated ‘language’ of production and consumption. Far from being geared simply to academic questions, however, the project team is keen to ensure that their findings reach the widest possible audience, not least because maps are enduringly popular objects and always capture the imagination; medieval maps especially.
To this end one of the main project outcomes is a web-resource through which the Gough Map will be made more widely accessible (it currently resides in the Bodleian Library), and through which the data and findings of this project will be made freely available. This will help others to develop the research, whether in academic or non-academic sectors. As well as the web-resource, the project will provide the basis for a public exhibition on the Gough Map, to be held at the Bodleian Library, Oxford, at which a colloquium will provide a forum for discussion on the language and linguistics of medieval maps and mapping.
The Gough Map © The Bodleian Library
[Canadian] Department of Foreign Affairs and International Trade Programme Development Grant Mineral Prospecting, Financial Speculation & Regulating Grounds for Belief Dr Niall Majury
Company, Crown and Colony: The Hudson¹s Bay Company on Vancouver Island
Steve Royle is The Eccles Centre Visiting Fellow in North American StudiesThis award was made for the 'best proposal in research at the British Library' by the British Association for American Studies together with the British Association for Canadian Studies and the Eccles Centre at the British Library.
The project is to study the Hudson's Bay Company on Vancouver Island, Canadafrom 1843 when they set up a trading post at Fort Victoria through to and following on from the 1849-1859 period when the Company ruled the island under licence from the British Crown. The tensions between the operation of a commercial company and the same people forming a colonial government were exquisite, to say nothing of the constant strife between the Europeans and the First Nations as the local indigenous people were not called then.
The photographs are of the crest of the Hudson's Bay Company (which still exists and runs The Bay department stores), the British Library and the researcher posing beside a cardboard cut-out of Governor James Douglas, from 1851-59 Governor and Vice-Admiral of the short-lived Vancouver Island Colony as well as being a Chief Factor of the Hudson's Bay Company. That photograph was taken outside the British Columbia Archives in the city of Victoria, the modern counterpart of the log-built stockade of 1843.
Under the umbrella of the joint AHRC/EPSRC initiative on Heritage Science, Prof. Bernard Smith, together with Dr John Hughes (University of the West of Scotland) and Dr Martin Lee (University of Glasgow) have been funded to set up and run a one-year research network during 2009 entitled:
Transformation and resilience of our cultural landscapes, archaeology and built heritage: defining responses to societal and environmental pressures
Background to the Network
Cultural Heritage will, in the near future, be subject to substantial transformation in response to changing climate. Mitigation and adaptation is affecting economic governance, and introducing sustainability pressures on buildings and landscape (e.g. thermal efficiency, renewables), in addition to direct physical, chemical and organic impacts from the changing environment (e.g. coastal erosion, landslides, material dissolution, microbial colonisation). Affects will occur on a range of scales that will drive changes in conservation needs. We desperately need to understand the resilience of the Cultural Heritage against these transformational pressures, from a material perspective, but also how we can be more effective in decision-making and management from government to citizen level. A complex interaction exists between social and material aspects; scientific understanding and innovation plays a central part in our perceptions and valuation of the Cultural Heritage. In order to meet future challenges there is a need to develop effective, adaptable management and decision-making policies and methodologies, that utilise to best effect the latest scientific and technological developments. The network therefore aims to establish, in a regional context for Scotland and Northern Ireland, a unified and interdisciplinary response to these threats and opportunities for innovation. The programme for the network is based around an examination of the threats posed to three UK World Heritage Sites that encompass a range of heritage types, threats and values. These are The Giant’s Causeway (natural heritage), Orkneys (archaeological heritage) and Edinburgh (built heritage). Three workshops are planned, one at each location, with the one in Edinburgh used to formulate future strategies for managing change at these and similar locations.
The overall aim is to understand how periods of prolonged, deep-seated wetness impact on the 'greening', deterioration and potential conservation of sandstone masonry, through an interdisciplinary study linking civil engineering, geomorphology, climatology and environmental microbiology with architects and conservators.
Specific objectivesSpecific objectives needed to meet the overall aim are listed below.1. To understand the current greening of sandstone walls typical of that found across the NW UK today and its relationship to climate, air quality and micro-environmental conditions. 2. To monitor the moisture contents of sandstone test walls to quantify 'time of wetness' (both at the surface and at depth) in the west of Northern Ireland and its relationship to greening. 3. To relate wetness regimes in sandstone walls to existing climatic conditions. 4. To determine future wetness regimes in sandstone walls through statistically downscaling climate projections and utilising links between wetness and climatic parameters discovered in objective 3. 5. To investigate the relationship between moisture levels and ion diffusion of key anions and cations within sandstone blocks and their potential significance for sandstone deterioration. 6. To investigate the links between greening (algal colonisation) of sandstone blocks and moisture regimes and deterioration and to develop and test new conceptual models of sandstone deterioration under wetter, 'greener' conditions. 7. To devise practical advice for building with sandstone and managing the greening and deterioration of existing sandstone walls under wet conditions. Duration
PIProf. B.Smith Co-PI for Oxford
University of Oxford c.£320k
Queen’s University Belfast £392k
Prof M. Basheer,
Dr N. Betts,
Dr J. McAlister
Prf. A. Whiteley