Recumbent folds between Glen Roy and Lismore

Abstract

Synopsis Moinian and Lower Dalradian metasediments between Glen Roy and Lismore are folded by structures belonging to two main phases of deformation. D1 folds are isoclinal and regionally recumbent whereas D2 folds are tight to isoclinal and upright. New information indicates that two structures previously regarded as major recumbent synclines can no longer be accepted as D1 folds. One, the Ballachulish Syncline, was postulated on false stratigraphic criteria and is considered to be non-existent. The other, the Appin Synform, is a D2 fold which locally refolds D1 isoclines, an example being the Balygrundle Syncline† on Lismore. Recumbent folds up to 20 km in amplitude are confined to the area between Kinlochleven and Loch Treig where the Treig Syncline† underlines the Kinlochleven Anticline. Both these structures are refolded by the Blackwater Synform and the Inverlair Antiform†. (†Structure described for the first time)