Thermal metamorphism of pyrite. North Ballachulish Slate Quarry скачать в хорошем качестве

Thermal metamorphism of pyrite. North Ballachulish Slate Quarry

Thermal metamorphism due to igneous intrusions can bake soft sediments into very hard contact metamorphic rocks. The Ballachulish igneous complex has a world-famous contact metamorphic zone (or aureole) which shows the full range of thermal metamorphism, form low grade where individual minerals are altered, to the highest grade where the surrounding rock starts to melt. Release of volatiles is typical of metamorphic reactions caused by increases in tempertaure - normally the gasses released would ne water or CO2, ut around 500-650 C any pyrite (FeS2) in the rock will lose sulphur to make the high-temperature form pyrrhotite (Fe-1x)S. As we saw last week, the graphite slates of Ballachuiish can be very pyrite rich aso a lot of pyrrhotite was formed here. It is unstable in air and weathers away to leave large cubic cavities visible all over the quarry faces. Graphite Slate, Ballachulish:    • Deep Sea Graphite Slate: Ballahulish Slate...