Geophysics day seven – depth-scanning and a new batch of beginners

Our second geophysics open afternoon took place this afternoon, with a new group of beginners shown the ropes by Paul and Chris.

Again, their test surveys focused on the area over the southern boundary wall and they were able to see their results before departing. The event was part of our National Lottery Heritage Fund-funded Past, Present and Future outreach project.

Elsewhere on site, Chris had his magnetometer back out and was focusing on an area between the excavation site and the Loch of Stenness.

Meanwhile, Travis, Ray and Sigurd “depth scanned” three 20-metre square grids beside and over Trench P. For these, the resistivity gear sends out three electrical charges at different depths, the results showing separate “slices” at 50cm, one metre and 1.5 metres deep.

Because this process is slower than a normal resistivity scan, it meant we could cover less ground in the available time. But the results were worth it, with anomalies at the lowest depth much clearer than those we recorded last week.

We’ll be rescanning more areas tomorrow to supplement and clarify our previous results.