Re-Os geochronology of the Neoproterozoic-Cambrian Dalradian Supergroup of Scotland and Ireland: Implications for Neoproterozoic stratigraphy, glaciations and Re-Os systematics

We also report a young, highly imprecise Re-Os age (310 ± 110 Ma) for the Early Cambrian Leny Limestone Formation which is constrained biostratigraphically by a polymerid and miomerid trilobite fauna. We suggest, based on the mineralogy of the Leny Limestone, (kaolinite, muscovite and a serpentine group mineral, berthierine), that the Re-Os systematics have been disturbed by post-depositional fluid flow associated with Palaeozoic igneous intrusions. However, it is evident from the Ballachulish Slate Formation results that anhydrous metamorphism does not disturb the Re-Os geochronometer.