Barron, H F, Gillespie, M R and Merritt, J W 2011. Geodiversity of the Cairngorms National Park. British Geological Survey Open Report, OR/10/019 A PDF of this report is available from the NORA, the NERC archive
Site no.: B8
Site name: Dorback
Grid reference:
Locality: Allt Iomadaidh, between Dorback Lodge and Bridge of Brown
GCR Status: N/A
GCR No.: N/A
Type: Natural exposures
Description: Exposures in the small Letteraitich Diorite- granodiorite Pluton (part of the Dorback Cluster).
Justification: The site encompasses the only significant occurrence within the CNP of appinitic igneous rocks. These are relatively rare rocks, in Scotland and globally, characterised by abundant large crystals of the mineral hornblende in intrusions of broadly dioritic composition. They are thought to be a product of fluid-rich magmas derived from the mantle. The Letteraitich pluton is also a representative of the South Grampian Subsuite of late-Caledonian intrusions.