serie NOVA TERRA nº 49

122 associated with the activity of a mature and evolved magmatic arc dur- ing the Late Precambrian and Early Cambrian. The record of this transi- tion in the CIZ depicts an evolving tectonic scenario from a convergent and active setting to an extensional context, prior to the development of a Cambro-Ordovician passive margin. This transition represents a drift of the major magmatic activity of the arc system to a more distal position from the Gondwana margin along the Late Neoproterozoic, while the basins towards the mainland remain very distant from the main axis of volcanic arc activity during Early Cambrian times. Acknowledgments Financial support has been provided by the Spanish projects CGL2012-34618 and CGL2013-48877 (Ministerio de Economía y Competitividad). Insightful reviews of the manuscript performed by anonymous referees are gratefully acknowledged, as well as the impor- tant editorial work of Brendan Murphy aimed at improving the fi nal version of the present work. 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