Hydrothermal fluid pathways at the contact of the Beinn an Dubhaich epigranite, Isle of Skye

Synopsis Field observations and Sr and Pb isotopic evidence point to the existence of two phases of hydrothermal activity at the margin of the Beinn an Dubhaich epigranite. An early flux of magmatic fluids carried Pb and Sr outwards from the granite, passing along major channels in the Durness Limestone to form skarn deposits, but not penetrating into the body of the rock. A later inward flux of meteoric fluids carried Sr from the limestone into the margins of the granite, where it penetrated along small cooling joints and grain boundaries, causing minor contamination.