The Ediacaran-Early Cambrian detrital zircon record of NW Iberia: possible sources and paleogeographic constraints

摘要: Ediacaran and Early Cambrian sedimentary rocks from NW Iberia have been investigated for detrital zircon U–Pb ages. A total of 1,161 concordant ages were obtained in zircons separated four samples (3 the Cantabrian Zone one Central Iberian zone) two Lower (one Zone). Major trace elements including REE Sm–Nd isotopes also analyzed on same set samples. The stratigraphically older sequence has a maximum sedimentation age ca. 600 Ma based content is intruded by 590–580 granitoids constraining deposition this part between 580 Ma. younger 553 sample an identical within error 555 patterns are very similar all both zones main groups 0.55–0.75 Ga, 0.85–1.15 Ga minor Paleoproterozoic (ca. 1.9–2.1 Ga) Archean 2.4–2.6 populations. Kolmogorov–Smirnov statistical tests performed indicate that they derived parent population (i.e., source area). can be said basis Nd isotopes, element concentrations. samples, however, show contrasting signatures: lacks high proportion (>60 %) more negative eNd higher TDM values than distribution (based KS tests) as but significantly value. These data suggest apparently continuous realm northern Gondwana 550 changes influx around Ediacaran–Cambrian boundary. nature origin these cannot determined with available data, must involve tectonic activity margin evidenced angular unconformity separating strata Zone. absence apparent continuity became segmented significant transport flux relatively short distances. As to paleoposition Ediacaran–Early times, comparison presented herein wealth relevant literature European peri-Gondwanan terranes Africa suggests may lain closer present-day Egypt–Israel–Jordan area potential hitherto enigmatic Tonian–Stenian could traced exposed segments arc such described Sinai Peninsula (Be’eri-Shlevin et al. Geology 40:403–406, 2012).