Gardd Fotaneg Genedlaethol CymruNational Botanic Garden of WalesNational Botanic Garden of Wales
Garden blogs

Remote sensing


Geo-physical survey

As the historic parkland restoration progresses we are again working with archaeologists from the Dyfed Archaeological Trust to investigate the surviving remains of our Regency designed landscape.

As well as their trusty trowel and brush archaeologists have lots of modern scientific methods and techniques to help them locate and understand the buried remains of past activity.

This week the archaeologists have been using some very sophisticated geo-physical surveying equipment to locate buried remains without breaking the ground surface once! The piece of kit that Charlie Enright is using is a “fluxgate gradiometer” which detects minute variations in the earth’s magnetic field. Lots of things can cause these small variations including changes in the underlying geology. However past human activity can result in changes which are recognisable too.

Recognisable features

All sorts of activity can leave evidence that can be identified using this technique. In particular features such as silted ditches, hearths, in-filled pits, burnt remains and walls can all result in tiny changes in the earth’s magnetic field which can be measured by the equipment. These readings are recorded digitally and these initial results are visible within minutes of downloading the them into a computer. More processing of these results will be needed before it is possible to create a plot which will show us where there are unexpected changes which might indicate the presence of buried archaeological remains. However, it is not possible to be 100% confident in exactly what buried archaeological remains are present.

Volunteer archaeologists wanted

Using the results of the geophysical survey to guide them the archaeologist will next be digging a series of trial trenches to expose a sample of what the survey has located. If you have always wanted to try your hand at archaeological excavation this could be your chance to have a go. The trial trenching will be starting on the 25th September and continuing for about three weeks. Just contact Angharad Phillips, our project Administration and Volunteer Officer, on 01558 667177 or e-mail and sign up!