In recent years some white salt encrustations have been observed in the Fossil Grove. As well as on the rock surfaces, there are now some notictable ‘tram-lines’ of salt and water patches directly under the roof beams – which are forming due to high humidity and probable roof leaks.
Historic Environment Scotland have undertaken XRD (X-Ray Diffraction) studies of these white salts and discovered that those in the tramlines contain various magnesium sulphates. In the high and fluctuating humidity conditions in the building these salts are gradually breaking up the surface as they expand and contract.
Sampling of water as well as the roof materials is also being undertaken to try and ascertain the source of the magnesium salts.