Tectonic significance of a supra-ophiolitic sedimentary cover succession, Unst, Shetland, Scottish Caledonides: insights from the U–Pb–Hf detrital zircon record

The tectonic significance of the Muness Phyllite, which overlies Unst–Fetlar ophiolite in Shetland, Scottish Caledonides, is poorly understood. U–Pb analyses detrital zircons show that it was deposited after c . 469 Ma. Early Paleozoic grains have εHf values −0.3 to +12.3 and were probably derived from extension Midland Valley arc. Psammite clasts matrix Phyllite contain Proterozoic Archean with age peaks 1, 1.4–1.5, 1.6–1.7, 1.8–1.9 2.7 Ga. These are consistent ultimate derivation NE Laurentia sources recycled Neoproterozoic East Mainland Succession underlies Mesozoic Shetland Basin. interpreted been soon Grampian I orogeny a successor basin overstepped received detritus arc, ophiolite. It then deformed metamorphosed, at c. 450 Ma during II orogenic event. therefore provides record middle late Ordovician events along sector Laurentian margin following obduction. Supplementary material: Analytical details instrumentation parameters Lu–Hf isotopic data available https://doi.org/10.6084/m9.figshare.c.5324986