Near Surface Geophysical Studies
Cemetery Studies
Old or abandoned cemeteries present numerous challenges.
Their boundaries may be unknown because of unmarked burials or poor records. Some unregistered cemeteries lay hidden until they are disturbed by development.
Western Heritage uses magnetic detection and ground penetrating radar (GPR) to non-invasively locate unmarked burials and identify cemetery boundaries.
We can assess sites in most settings or conditions throughout the year.
Ground-Penetrating Radar
Ground-penetrating radar (GPR) uses reflected radar pulses to see under the earth's surface without digging or drilling.
GPR can be used on most surfaces and can detect subsurface changes to a depth of several metres.
Western Heritage uses GPR equipment from Sensors and Software, a leading Canadian manufacturer. Our SmartCart GPR unit collects and displays data in real time, and can be used in variable conditions or on difficult terrain.
GPR is ideal for:
- Industrial or historical sites known or suspected to hold buried cultural features or objects (pits, pipes, trenches, foundations or graves)
- Sites with hard surfaces, where digging is difficult
- Locations where intrusive excavation must be kept to a minimum
- Cemetery mapping and locating missing graves
Ground-penetrating radar works in many environments, and nearby electrical power sources are not an issue. Using GPR, we can evaluate large areas in real time and quickly process data to generate 3D maps of subsurface features - all with no excavation.
Magnetometry
Think of geophysics as a way of collecting new kinds of data from archaeological sites. Magnetometry is a branch of geophysics, and a tool for exploring the earth to learn about its nature and content.
Western Heritage can measure the magnetic properties of a site to locate and identify cultural features. We use a GeoScan FM256 Gradiometer as our primary magnetic data collector.
Magnetic surveys can show the location of pits, burn areas (campsite hearths), structural remains, iron artifacts and other features of vital interest to archaeological interpretation.
Magnetic Susceptibility
Magnetic susceptibility is a measure of a material's ability to become magnetised by an external magnetic field. The magnetic susceptibility of a soil reflects the presence of magnetic iron-oxide minerals, which can be formed by burning or microbial activity. Human activity has an important effect on magnetic susceptibility in soils - examples include fires or garbage decomposition. As a result, magnetic susceptibility is often used for site prospection. It can help identify areas of archaeological potential before excavation; it can also identify hearth areas and the presence of burning residues. When measured in a systematic way, magnetic susceptibility can be used to detect evidence of human occupation even when no distinctive archaeological features have survived.
