Friday, 28 April 2017
Geophysics Survey and training - update and some preliminary results
For 3 days in April volunteers took part in further survey training on the Chase,led by the Historic England geophysicist Andy Payne.
The two sites we surveyed were at:
i) Sheepwash Farm or Smart’s Buildings in the Slitting Mill Lane area of Cannock Chase District where the aim was to investigate the sites of one or more probable burnt mounds.
ii) A trial geophysical investigation of the accessible parts of the interior (where surface vegetation permitted) of the hillfort at Castle Ring, Cannock Wood .
(Photo credit : CTT Volunteer Zoe Mead)
Earth resistance and magnetometer surveys were undertaken at both sites.
To summarise the results really briefly, Andy think's we’ve confirmed that the southern of the three mounds visible in the Lidar in the southern field at Sheepwash Farm is almost certainly a burnt mound but the others are more doubtful. There’s also an interesting area of anomalous magnetic response (intense but not ferrous) in the field to the north where other burnt mound activity was suspected.
At Castle Ring as well as the previously known site of the Medieval ‘hunting lodge’ that is visible in the form of stone wall footings exposed on the surface following a previous excavation, the resistance survey appears to have detected remains of a further probable buried masonry structure to the south but on a different orientation as well as potentially associated linear boundaries perhaps defining paddocks (as previously suggested from the RCHME earthwork survey undertaken in the late 1980s.
By comparison the magnetometer coverage at Castle Ring was disappointing with very few clear features identified and a very marginal magnetic response in general that probably reflects the less than ideal underlying geology in the form of superficial deposits of Devensian glacial Till overlying Carboniferous Pennine Middle Coal Measures formation.
As a result, the interpretation of the magnetometer data can at best be very tentative. In addition to a very sparse scatter of possible pit or other occupation features, there may be one ring gully just about detected towards the eastern side but this is all very much “eye of faith”. Areas of localised strong ferrous disturbance may relate to some of the possible WW2 structures referred to in the earthwork survey report.
Andy and his team will start working on the formal Historic England Research Report Series reports on the results in due course and will keep us informed on progress with these.