AN INTEGRATED GEOPHYSICAL APPROACH TO STONEHENGE C. Gaffney, V. Gaffney, W. Neubauer, E. Baldwin, K. Löcker The extent of previous geophysical prospection within the Stone- henge World Heritage Site up to 2001 has been estimated at 3.1602 square kilometres (David, 2005, 14). Since that time, additional geophysical survey in the area probably amounts to about 0.8 square kilometres. The nature, spatial locations and extent of previous geophysical prospection work within the study area are broadly driven either by reactive evaluation strate- gies determined by the planning process and mitigation of pro- posed development, or by monument-focused research agenda, resulting in discontinuous, fragmentary, relatively small-scale and often linear rather than spatially-extensive survey areas (Payne, 1995, 2006; David and Payne, 1997; David, 2005; Darvill, 2005). These surveys have developed what we may re- gard as traditional monument/site-focused approach to field in- vestigation. This has been a valid approach to answer specific project objectives. However, prior to the Stonehenge Hidden Landscape Project (SHLP), less than 4.0 square kilometres of the landscape have been subject to geophysical survey of diverse types, with variable data resolution and uneven and fragmented spatial coverage. In contrast, the SHLP is producing a coher- ent high-intensity geophysical survey encompassing much of the World Heritage Site, providing high-resolution, contiguous ex- tensive mapping of geophysical data. As has been described in related articles and presentations (Gaffney et al., 2012; Gaffney et al., 2013) the intention of the SHLP is to explore landscape as undivided three-dimensional space and to understand ancient built environments and associ- ated practices at extensive scales within that spatial framework. The results of this work form the basis of a highly detailed ar- chaeological map of the ‘invisible’ landscape, providing the ba- sis for a full interpretative synthesis of all existing remote sens- ing and geophysical data from the study area, as well as compar- ative evaluation of the results of archaeological excavation data in relation to geophysical results. The creation of total digital models of the Stonehenge landscape at a true ‘landscape scale’ that will not only transcend the immediate surrounds of individ- ual monuments within the study area, but will also tie them to- gether within a seamless map of sub-surface and surface archae- ological features and structures. The massive scale and compre- hensive nature of this dataset will allow for posing new questions about the past not possible using only information from surface remains or limited excavations. At the centre of the project phi- losophy is that the invisible landscape around the highly visible monument of Stonehenge remains key to the understanding of the monument itself. In order to fulfil the objectives identified in Gaffney et al. (2013) there has been a requirement to take a significantly differ- ent approach to non-invasive work in the Stonehenge ‘envelope’ (defined by Cleal and Allen, 1995). There is a need to produce extensive but detailed data sets, which provide archaeological, pedological and geological information at differing depths. Ge- ologically much of the survey area is said to lie above Late Cre- taceous Chalk (Calcium Carbonate) approximately 85 million years old; the top layer is degraded by periglacial weathering during the last glaciation, which produced the underlying frac- ture patterns. The land has mostly been used for agricultural, but modern use, including ‘festivals’ and military activities, is well documented. The rolling landscape includes areas of both thin and deep soil cover, and mapping using a single technique, no matter how embedded in previous work, was not a supportable position. As a result, the SHLP has developed a strategy for ground- based survey that is both extensive and flexible in the approach to a large landscape. Table 1 summarises the range of geophys- ical and other remote sensing data collection systems currently being used by the project team. The data rich environment that has been produced clearly relates to the primary objective of the project, which is to produce an uninterrupted dataset of above and below ground remains for archaeological analysis and rein- terpretation within the context of the wider Stonehenge land- scape. In this presentation, the integration of differing techniques within the strategy will be illustrated, especially with respect to the objectives of the project. It will evident, even in a well pro- visioned project such as SHLP, that the key to success is deploy- ment of appropriate techniques. REFERENCES CLEAL RMJ, ALLEN MJ. 1995. The visual envelope. In Stone- henge in its Landscape: Twentieth Century Excavations, Cleal RMJ, Walker KE, Montague R (eds). English Heritage: Lon- don; 34–40. DAVID A. 2005. Ground-based geophysical surveys. In Stone- henge World Heritage Site: an archaeological research frame- work, Darvill T (ed.). English Heritage and Bournemouth Uni- versity: London and Bournemouth; 14–15. DAVID A, PAYNE A. 1997. Geophysical surveys within the Stonehenge Landscape: a review of past endeavour and future potential. In Science and Stonehenge, Cunliffe B, Renfrew C (eds.). Proceedings of the British Academy, 92: Oxford; 73– 113. DARVILL T (ed.). 2005. Stonehenge World Heritage Site: an archaeological research framework. English Heritage and Bournemouth University: London and Bournemouth. GAFFNEY C, GAFFNEY V, NEUBAUER W, et al. 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