Just as the historic environment is an important consideration in the planning process, geoarchaeology is key to predicting and understanding archaeological sites that might coincide with a development.

Geoarchaeological works are carried out carried out at various stages of the planning process:

• geoarchaeological desk-based assessments (gDBA) at the pre-application stage

• borehole and test-pit surveys following the submission of planning applications

• studies of sediment layers revealed in archaeological excavations as mitigation for development

In the case of gDBAs, borehole and test-pit surveys, the geoarchaeological approach enables improved targeting of conventional archaeological investigation, for example by indicating which areas and/or layers are most likely to contain artefacts and features. Geoarchaeological studies during these early project stages often allow for resource savings at later phases.

Borehole and geoarchaeological test-pit surveys also provide stratigraphic context for the remains found in archaeological trenches, aiding in their interpretation. Indeed, certain types of evidence for human activity can only be found using geoarchaeological methodologies. For example, geochemical studies can reveal residues of metal-working activities; study of the magnetic record can provide evidence for use of fire, and palaeobotanical remains can demonstrate human modification of the vegetation.

Geoarchaeological approaches applied to archaeological stratigraphy can also include the study of ‘thin sections‘ (thin slices of sediment studied under a microscope) of ancient soils and sediments. Such micromorphological approaches can reveal detail of past human activity that is not visible with the naked eye, e.g. whether a soil was used for pasture or cultivated, and if used for arable purposes, what the nature of that regime was.

In short, geoarchaeology is an inherent and important part of the historic environment investigation process. ARCA is one of very few independent organisations that can advise on and carry out geoarchaeology work at all planning stages.

Image top: Prof. Keith Wilkinson, Dr Phil Marter and Will Reid carrying out work in central Winchester, against the backdrop of the iconic Winchester Cathedral.