Geophysical and Non-intrusive Survey

Our Suffolk office can provide a range of non-intrusive investigation techniques to establish the potential of a site for archaeological deposits or other heritage assets without causing any disturbance. The suitability and requirement for different techniques will depend upon the nature of each individual site …

Geophysical survey

Geophysical magnetometer survey of a golf course, Norfolk

Geophysical surveys are often required by local planning authorities or their archaeological advisors at an early stage in the planning process. These rapid and cost-effective surveys are commonly undertaken to establish and map the presence or absence of any surviving potential archaeological remains or areas of modern disturbance within a proposed development area.

The geophysical survey results are conveyed within a detailed technical report, accompanied by a GIS dataset. Each report will include an interpretation of the results and can indicate the presence of buried archaeological or geological features. Such reports, often in conjunction with other desk-based assessment or non-intrusive surveys, allow the planning authority and its archaeological advisor to make decisions about a sites archaeological potential and need for subsequent stages of site investigation such as targeted trial-trench evaluation. Such further work is typically required to 'ground truth' the results of a geophysical survey but the scope and extent of such works can often be reduced.

Greyscale plot of results from a magnetometer survey at Mildenhall

Interpreted plot of results from a magnetometer survey at Mildenhall

Suffolk Archaeology's dedicated geophysical survey team can undertake both large and small survey projects and currently offers the following types of survey in-house;

Magnetometer survey in Woolpit, SuffolkMagnetometer Survey:

The most commonly used survey technique in archaeological geophysics, employed to prospect anomalies indicative of archaeological settlement and industry. Large open areas can be accurately and rapidly surveyed with either cart-mounted arrays, or hand-held instruments over rough or uneven terrain.

Earth Resistance Meter survey at Abbey Farm, HoxneEarth Resistance Meter Survey:

A technique that is best targeted to prospect for structural remains buried below the ground surface. Pits, ditches and moisture holding deposits are also routinely recorded.

GPR survey at Bungay CastleGround Penetrating Radar Survey:

Ground penetrating radar (GPR) uses a transmitter to emit an electromagnetic pulse into the ground. When a change in the boundary between materials or a buried object is encountered, the energy from the pulse is either reflected,refracted or scattered back to the receiving antenna which records the variations. The best results from a GPR survey are achieved where well defined changes in the electromagnetic properties of deposits are encountered and it is therefore good at prospecting for service pipes, buried buildings and changes in stratigraphic soil horizons, it can also record voids within structures. Depth measurements can also be estimated depending on the soil types encountered.

Using a Magnetic Susceptibility Meter

Magnetic Susceptibility Meter Survey:

Magnetic susceptibility meter survey is employed to locate soils with an increased magnetic susceptibility, these high peak readings can reveal areas of settlement activity and habitation within a wide landscape. The coil attached to the end of the instrument is placed on the ground surface (typically points are recorded at 5 or 10m centres) a weak alternating current is then injected through the topsoil; the magnetisation of the material is then detected and its magnetic susceptibility calculated.

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Field walking and metal-detecting surveys

Metal detecting ahead of an excavation site strip at Barton Mills, Suffolk

We can carry out fieldwalking surveys of suitable sites to locate, collect and record any archaeological finds material visible on the ground surface, with metal-detecting to recover metalwork finds from topsoil deposits. The resulting analytical report can be used to highlight if a site has archaeological potential, and identify specific areas of interest for future investigation by methods such as trial-trenching.


Surveying at Bawdsey, Suffolk

We are able to provide systematic and accurate recording of site topography or structures using a GPS or Total Station. Topographic surveys and 3D modelling can be used to identify and map surviving earthworks and landscape features, or to plot the extent and scope of past groundworks that may have affected archaeological or historic sites.

Such digital recording in tandem with photography can allow the rapid production of detailed surveys, particularly of structural features and so is often used to support Historic Building Recording projects. A detailed report will interpret results, often in conjunction with other survey techniques or the results of desk-based research, and can aid in the characterisation of a site, inform further investigation or in the design of mitigation strategies.

Aerial Photography

Elevated site photography at RAF Lakenheath using a custom-built mast and  mounted remote controlled camera

Suffolk Archaeology is able to take elevated or aerial photography using pole mounted or tethered kite cameras in-house. Such photography is typically used as a tool within our fieldwork projects, for example in recording specific archaeological features such as large structures, or entire evaluation or excavation sites.

We can also commission specialist drone or aircraft aerial surveys, either to record our fieldwork projects within their wider landscape setting, or to carry out stand-alone projects such as earthwork or cropmark surveys examining the landscape from the air.

Case study

Bungay Castle, Suffolk

Fluxgate gradiometer, earth resistance meter and ground penetrating radar surveys on at Bungay Castle, Suffolk.

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Case study

Abbey Farm, Hoxne, Suffolk

Earth Resistance Meter survey at Abbey Farm, HoxneEarth Resistivity and Ground Penetrating Radar surveys at Abbey Farm, Hoxne was carried out in 2017 at the request of the landowner, with the aim of finding evidence for the location and survival of the former buildings of a medieval Benedictine Priory and the Chapel of St Edmund.

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Case Study

World War II uncovered: Touching the Tide

A WWII pillbox at Bawdsey, Suffolk

As part of the Heritage Lottery Fund project ‘Touching the Tide’ Suffolk Archaeology carried out a survey of WWII heritage assets of the Suffolk coastline at Bawdsey, Sizewell and Walberswick.

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