30^th March 2024 - Hydrothermal Barite

Today I want to talk about some hydrothermal barite viens that I came across when doing some fieldwork in North Glen Sannox, Arran. Glen Sannox has had a history of industry and mining - though since 1938 it has been abandoned. Here's some pictures of the site/area:

The sample (as shown below) belongs to the area's native conglomerates (part of the Am Binnein Sandstone Formation, itself part of the Devonian Old Red Sandstone) intruded by hydrothermal barite, that has crystalised along the rock's bedding plains. As these rocks fall into the Lower Devonian epoch, they can be dated to around 419.2-393.3 million years old. Glen Sannox's conglomerates are generally supported by well-rounded pebble-sized quartz clasts, surrounded by a fine to coarse quartz matrix, bound by a iron-oxide cement. The barite crystals themselves appear in a range of texutes - including fiberous, amorphous and tabular. Interestingly (I'd hope), the barite is joined by an accesory mineral: Epidote, which has formed alongside the barite bulk. Overall, I value this sample quite a lot, as it has quite a lot to show for in such a small space and demonstrates some lovely intrusive relationships.