Abstract

The tectonostratigraphic record of the Avalon terrane in southern New Brunswick is interpreted as that of a Wilson cycle that followed the Grenvillian and preceded the opening of lapetus. Development of a late Precambrian continental shelf is attributed to the ?Cadomian ocean whose initial subduction at ∼800 Ma led to platform collapse, regional metamorphism, and minor mafic to ultramafic plutonism, in response to back-arc extension and crustal separation. Oblique subduction of the resulting back-arc basin at ∼600–630 Ma produced calcalkaline plutonism and cogenetic volcanism that ended in dextral transtension and the emplacement of a bimodal dike complex. Initial rifting of lapetus, which isolated this record from cratonic North America, is recorded in Eocambrian redbeds and bimodal volcanics and produced a Cambro-Ordovician overlap sequence bearing Acado-Baltic fauna.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.