Abstract

The provenance of turbidites from the predominantly Arenig-aged Manx Group has been constrained using petrographical and geochemical techniques. Petrographical analysis of sandstones reveals that mono- and poly-crystalline quartz grains of cratonic origin are dominant. Major, trace and rare earth element concentrations in both sandstones and mudstones complement the petrographical data indicating that the source of the sediments consisted of quartzose basement and mature sedimentary rocks. There is little evidence of a juvenile volcanic input but a minor palaeovolcanic component of active continental margin affinity is present. There are indications of a more immature character in the oldest units but, on the whole, geochemical data from the Manx Group suggest an overall passive margin setting. These results suggest that Eastern Avalonia was attached to Gondwana during deposition of the Manx Group and that Iapetus oceanic crust did not subduct beneath the region before the end of the Arenig.

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