A LATE VENDIAN AGE FOR THE KINLOCHLAGGAN BOULDER BED (DALRADIAN)

The Kinlochlaggan Boulder Bed occurs in Neoproterozoic Dalradian rocks of the Grampian Mountains of Scotland. It is currently thought to rep resent a glacial event (c. 800 Ma) unique in the North Atlantic region , and be part of a sequence correlated by different workers with eithe r the Grampian or Appin groups. We correlate the Boulder Bed with the Port Askaig Tillite of Vendian (e. 650 Ma) age, and deduce that the se quence in which it occurs belongs to the younger Argyll Group. The lat ter is preserved within the D2 Kinlochlaggan Synform, and a previously unrecognized discontinuity of regional importance may separate invert ed Argyll Group rocks from the underlying Grampian Group.