J. M. Leigh Surveys offers a suite of geophysical services. The main geophysical techniques which we recommend are magnetic surveys and resistance surveys. These techniques are an invaluable tool for archaeological prospection.

Magnetic Survey
Examples of features detectable: Occupation Areas Archaeological Pits Hearths Kilns Ditched Enclosures Fulachta Fiadh Ridge & Furrow Cultivation Ritual Sites Ecclesiastical Sites

Magnetic gradiometer survey has been adapted for use in archaeology and J. M. Leigh Surveys uses specifically designed equipment and software for archaeological prospection
Typical archaeological features which can be identified with magnetometer surveys include: ditches, occupational activity, burnt features such as hearths and kilns.

Field survey with gradiometer instruments is also considerably faster than any other current technique. Methodology of survey can be adapted for site type and size. A methodology called gradiometer scanning is often used on large sites, where full detailed survey is impractical. The preliminary survey is then followed up with a targeted detailed survey investigation. Detailed survey records instrument readings taken at a 1m traverse and 0.25m sample intervals.

Resistance Survey
Examples of features detectable: Building remains Ecclesiastical Sites Buried Paving / Floors Brick Foundations Souterrain Features

Resistance survey can be highly effective in locating buried archaeological remains. A small electrical current is applied to the ground and the resulting Earth Resistance is recorded. This technique is especially effective at locating buried building remains and structural features. It is often applied in conjunction with gradiometer survey in areas where building remains are suggested or suspected. The methodology employed is often site specific but as a general rule readings are taken every 1m along a 1m traverse.