Magnetometry

During a two-week period (3rd – 8th July 2017 and 24th – 30th July 2017) geophysical training for archaeological prospection was provided by Patricia Voke (Wessex Archaeology) for two groups of Libyan and Tunisian professionals at the site of Iunca, Al Mahres, Tunisia.

Training team

Patricia Voke (Wessex Archaeology)

Objectives

The purpose of the training was to introduce archaeological geophysical prospection and the application of different methods of geophysical survey. Then train the students to use a fluxgate gradiometer and carry out a magnetometry survey of the inside of the Fort at Iunca. Then the trainees would be taught how to process and interpret geophysical data. Unfortunately, due to the geophysical equipment being impounded at customs in the airport, the training schedule was not able to fulfil all the original aims and objectives. During the second week of the geophysical survey, training was provided although somewhat reduced from what was originally planned. However, it was at the time that it was possible to carry out further geophysical surveys to provide new information and research for the site at Iunca.

Training

A detailed gradiometer survey was also conducted over several sites surrounding the Fort at Iunca, Al Mahres, Tunisia. The project focused on the area directly east and north of the outside of the Fort at Iunca. One site approximately 0.3km south of the Fort and the final area directly north of three, previously excavated churches. These surveys aimed to establish the presence or otherwise, and nature of detectable archaeological features in these areas.

Several archaeological anomalies were identified within the four areas of geophysical survey at Iunca.

Results

As a result of the training, each trainee will have a much better understanding of the role of archaeological geophysical survey, its applications and limitations. They should have good knowledge on several geophysical techniques and be able to determine on a site by site basis what is the appropriate survey to carry out.

Each trainee will have gained the ability to assess an archaeological landscape as a whole, design specific research aims and utilise geophysical survey where appropriate to meet these objectives. They will also have a good understanding of gradiometer survey and where, what and when to use this technique.

All trainees will have gained lasting skills and experience on how to set up a survey grid using tapes and Total Station. These skills will not only assist them to create efficient and accurate survey grids for geophysics but should also provide them with survey skills which can be utilised in other archaeological investigations; such as grid layouts for excavation and field walking.

The extensive total station training will also have provided them with the ability to carry out accurate metric surveys to map and locate the geophysical data. This training will complement the training they received in photogrammetry and building recording in week 2 of the Training in Action project.

Each candidate will have a basic understanding of how to put together the Bartington gradiometer and how to calibrate the instrument. They will also have a basic understanding of how to collect accurate survey data.

Finally, each trainee should have gained knowledge on how to download and initially process geophysical data.