An investigation of the dissolution of a marble petroglyph site by acidic precipitation

The effects of acidic precipitation (acid rain) on a marble rock art site at Petroglyphs Provincial Park, Ontario, Canada have been investigated as part of a larger study to determine an appropriate course of action to protect the site from further deterioration. Experiments and chemical analyses indicate that the maximum recession rate due to solution weathering at the petroglyph site, where the average rainfall pH is 4, would be 29μm per year and that, at the present rainfall acidity, the extent of dissolution is not greatly increased over that of pre-industrial rainfall with a pH of 5·6.