Terrane analysis along a Neoproterozoic active margin of Gondwana: Insights from U-Pb zircon geochronology

Abstract

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.