Abstract The recent discovery of Ediacaran ophiolites in the SW Iberian Massif has made it possible to pinpoint the evolution of the Cadomian basement of Europe. The Calzadilla and Mérida ophiolites (gabbroic protoliths dated at c. 600 and 594 Ma, respectively) have geochemical characteristics typical of supra-subduction zone ophiolites. They are interpreted as originating during the initial opening of a forearc basin with boninitic magmatism (Calzadilla), followed by the formation of a back-arc basin with arc-tholeiites (Mérida). Widening of the back-arc led to the rifting and drifting of a section of the active continental margin (Cadomia). Closure of these oceanic domains initiated rapid contraction, culminating in the collision of Cadomia with Gondwana ( c. 590–540 Ma). The application of a PANALESIS model to this palaeogeographic setting confirms the plausibility of Cadomian rifting and the likely opening of broad oceanic domains. It also confirms the final collision of Cadomia with Gondwana, although the synthetic and regional data disagree in the precise chronology of the convergence and collision of Cadomia with the West Africa Craton. This work shows that the evolution of the Cadomian basement is much more complex than traditionally considered.

Abstract Special Publication 542 is a tribute to the remarkable career of J. Brendan Murphy and features 32 articles by 134 authors from 17 different countries; a testament to the high-profile and far-reaching influence of Brendan's work. The topics are wide-ranging in accord with Brendan's diverse research interests, but fall into three broad categories that encompass Brendan's main fields of influence: (i) supercontinents and the supercontinent cycle, including reconstructions and modelling, (ii) orogenesis and terranes, with a focus on the Appalachian–Variscan and Central Asian orogenic belts and the oceans with which they are associated and (iii) magmatism and magmatic processes, with an emphasis on the geochemistry and isotopic compositions of magmas in arc and rift settings. Like Brendan's own research, the scope of the papers spans the globe from Canada to China and ranges from regional field-based studies to conceptual global analyses. All of the articles, however, are focused on unravelling some critical aspect of geology or aimed at clarifying some crucial geologic process. Hence they also share a theme common to Brendan's many contributions in emphasizing the importance of process-oriented research.