Terrane analysis along a Neoproterozoic active margin of Gondwana: insights from U–Pb zircon geochronology

The tectonic affinities of terranes in accretionary orogens can be evaluated using geochronological techniques. U–Pb zircon data obtained from paragneisses of the Coedana Complex (Anglesey) and the Malverns Complex, southern Britain, indicate that they were deposited during the mid- to late Neoproterozoic and have a comparable Amazonian provenance. Metamorphism of the Coedana gneisses occurred at 666 ± 7 Ma, similar to the age of metamorphism in the Malverns Complex. Anglesey therefore probably evolved in proximity to the Avalonian basement of mainland southern Britain during the mid- to late Neoproterozoic and is not a ‘suspect terrane’ relative to the remainder of Avalonia.