Reconstructing the prehistoric landscape of Stonehenge (UK) through electromagnetic induction survey.

 

The Stonehenge landscape has been the focal point of archaeological studies for more than four centuries. However, until today no intensive mapping of the Stonehenge soil has been conducted. To understand the past human-landscape interactions that have shaped the Stonehenge landscape, detailed palaeolandscape information is indispensable. This interdisciplinary research project aims to bridge that gap by reconstructing the past Stonehenge landscape through multi-receiver frequency domain electromagnetic induction (EMI) surveying. The research consists of four segments, situated in the domains of soil science, archaeology, near surface geophysics and electrical engineering.

The first segment addresses methodological constraints in the use of multi-receiver EMI sensors. More specifically it will address current accuracy issues which occur when dense measurements are conducted at a landscape scale. Particular focus will be on the stability of different coil configurations in ‘Slingram’ frequency domain EMI sensors for in-phase measurements of the apparent soil magnetic susceptibility.

 

Mobile multi-receiver EMI survey at Stonehenge
Mobile multi-receiver EMI survey at Stonehenge

The second part concerns processing multi-layered EMI datasets, and discerning between recent disturbances, archaeology and natural soil variation. At Stonehenge, one challenge lies in separating the influence of recent land-use from the underlying archaeological and pedological features. Most notably, metallic debris, such as bottle caps and drinking cans, left behind after the music festivals in the 1970’s and -80’s, cause a snow curtain of small spikes in geophysical survey data, and obscure the underlying archaeology.

A third research segment addresses connecting observed electromagnetic variations to specific soil properties. A large part will focus on correlating magnetic susceptibility variations to soil properties. While EMI sensors are widely used for describing soil variations through electrical conductivity mapping, the magnetic signal component is far less applied for understanding pedological variability. At Stonehenge, the gathered EMI data will be combined with the different available geophysical datasets to reconstruct the palaeolandscape in three dimensions.

In a final stage, the gathered information of the natural and anthropogenic variations at Stonehenge will be combined to create a comprehensive reconstruction of its prehistoric landscape. This step will include the integration of the gathered EMI data into the archaeological survey dataset gathered within the framework of the Stonehenge Hidden Landscapes project (LBI ArchPro, University of Birmingham).

This research is funded by the Research Foundation Flanders (FWO) through a postdoctoral research grant (nr.: FWO13/PDO/046).

More information:
dr. Philippe De Smedt
Philippe.DeSmedt@UGent.be
+32 9 264 60 42

Metal influence in EMI data from Stonehenge (left) and result from a metal detection procedure (right)
Metal influence in EMI data from Stonehenge (left) and result from a metal detection procedure (right)

A clear view on archaeology. Magnetic susceptibility data after metal removal from a first EMI survey at Stonehenge
A clear view on archaeology. Magnetic susceptibility data after metal removal from a first EMI survey at Stonehenge