In their quest to better understand the past, archaeologists also take great care to preserve the resting grounds of ancient artefacts. But this is not always easy in large digs.
The ‘Radiography of the Past-project’ has harnessed the skills of international research teams to develop the next generation of non-destructive approaches to archaeology, including aerial surveying and remote-sensing technology. This approach has unearthed new evidence from buried settlements across Southern, Central and Western Europe which sheds light on how Roman cities and societies were constructed.
The common, responsible approach to heritage management is designed to preserve the integrity of buried sites and their historical treasures. However, this approach may also result in a kind of passive protection that can lead to sites only being partially uncovered which, in turn, could give an incomplete picture of the location’s history – its complexity and scope.
Over the past two decades, a set of non-invasive methods for sub-surface prospection have been developed, making it possible for thousands of sites across the world to be analysed, interpreted and eventually visualised without any damage being done to the monuments themselves.
The Radio-Past project (funded under the EU’s Marie Curie Action programme) brought together four academic and two industrial partners to develop the next generation of integrated, non-destructive approaches to archaeology.
“We’ve developed some unusual combinations of existing technology to refine observations, detections and mapping procedures in the field of aerial archaeology and remote sensing,” says project coordinator Professor Cristina Corsi. “Aerial photography and mapping with data capture from remotely-controlled kites and drones now allow relatively low-cost and high-precision 3D mapping and interpretation, enhancing the speed and accuracy of survey operations.”
These techniques are already helping researchers to understand complex archaeological sites such as buried Roman settlements, a speciality of the project’s archaeological team.
Hundreds of Roman sites have been located throughout Europe and beyond, many featuring a wide range of well-preserved archaeological structures in the subsoil. They have given Radio-Past researchers an ideal opportunity to apply their intensive non-destructive survey techniques and test new non-invasive archaeological approaches.
A combination of techniques, including airborne remote-sensing, field or artefact surveys, ground-based geophysical surveys, topographical and geomorphologic surveys, field checks, and virtual reconstructions can provide a range of data and pictures of what lies beneath the surface. The objective was to develop new instruments to interpret and visualise results without the ground being broken.
“By integrating these approaches, we can produce maps of the underground features which not only help us to understand the general layout of the settlement, but also to target digging operations, in such a way that excavation can be considered as ‘ground-truthing’ (the collection of image data relating to real features and materials). This is used mainly to collect data about the chronology and the stratigraphy – the study of rock layers and layering of the site,” explains Prof. Corsi.
More than just developing techniques which create a “radiography” of what is still buried in the ground, the project set out to combine the resources and skills of its project partners to tackle every possible aspect of “non-destructive” approaches.
Radio-Past developed and tested these new techniques at archaeological sites, such as the buried Roman city of Ammaia in Northern Alentejo, Portugal. Using the techniques, “we now know how many streets this town had, and that they were arranged in a perfectly regular street network”, notes Prof. Corsi. The project also discovered that Ammaia’s monumental centre was an open public square which was probably the venue for markets and discussions on business and politics, perhaps.
At sites like Ammaia, known as open laboratories for research and experimentation, all the analysis and technical activities can be performed on location. “Test results from the open laboratories led to a series of standards in the diagnostics of large and complex sites, which should help the archaeology of the near future to decide which battery of techniques and approaches is best suited to be deployed in any situation,” says Prof. Corsi. With dissemination of these new techniques and instruments in mind, the Radio-Past consortium organised the mutual exchange of researchers between its partner institutions and is recruiting new researchers to help transfer knowledge and develop the research plans.