Ailnack gorge - black schists (graphitic pelite to semi-pelite)

NW of the Cairngorms 

SW of the Cairngorms 

SE of the Cairngorms 

 

Country rocks N of the Cairngorms

The following  notes on the geology of Abernethy are from Lionel Hinxman. He was responsible for mapping large areas around the Cairngorms for the Geological Survey between 1890 and 1915.

"The greater part of the area included in the parish is occupied by the metamorphic rocks—mica schists, quartz schists, and quartzites—of the Highlands. Of these rocks are formed the range of hills that runs eastwards from Loch Phitiulais to the head of Glen More, Carn Bheur, the Geal Chain, and the high ground of the Braes of Abernethy, extending northwards to the Cromdale Hills. The predominant rock over this area is mica schist, varying in character from a coarse gneissose schist to a fine-grained flagstone, such as the rocks seen at the Bridge of Brown, and on Cnoc Fergan, further to the east.

"In the deep gorges cut by the Ailnack water and its tributary, the Allt Dearcaige, bands of quartzite alternate with the mica schist. The quartzite is often deeply reddened with oxide of iron, as is denoted by the name Carn Ruadh-bruaich—the Red Brae. With the quartzite are associated bands of dark schist, containing graphite and grey crystalline limestone, which at one spot near the ford of the Ailnack becomes a white marble. Another band of limestone crops out along the course of the Allt Iomadaidh between Rynetnich and Strancamernich, and extends thence to the south-east along the slopes of the Carn Fhir Odhair. Limestone is also found near Ballantruim and Sliabhchlach, and at Speybridge.