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Key to deciphering the origin and tectonic setting of kimberlite magmatism is an accurate understanding of when they formed. Although determining absolute emplacement ages for kimberlites is challenging, recent methodological advances have contributed to a current database of >1,000 precisely dated kimberlite occurrences. Several profound findings emerge from kimberlite geochronology: kimberlites were absent in the first half of Earth history; most kimberlites were emplaced during the Mesozoic; kimberlite magma formation may be triggered by a variety of Earth processes (deep mantle plumes, subduction of oceanic lithosphere, continental rifting); and enhanced periods of kimberlite magmatism coincide with supercontinent breakup.

The Caledonides of Britain and Ireland include terranes attributed to both Laurentian and Gondwanan sources, separated along the Solway line. Gondwanan elements to the south have been variably assigned to the domains Ganderia and East Avalonia. The Midland Platform forms the core of East Avalonia but its provenance is poorly known. Laser ablation split-stream analysis yields information about detrital zircon provenance by providing simultaneous U–Pb and Lu–Hf data from the same ablated volume. A sample of Red Callavia Sandstone from uppermost Cambrian Stage 3 of the Midland Platform yields a U–Pb age spectrum dominated by Neoproterozoic and Palaeoproterozoic sources, resembling those in the Welsh Basin, the Meguma Terrane of Nova Scotia and NW Africa. Initial εHf values suggest that the Neoproterozoic zircon component was derived mainly from crustal sources < 2 Ga, and imply that the more evolved Palaeoproterozoic grains were transported into the basin from an older source terrane, probably the Eburnean Orogen of West Africa. A sample from Cambrian Stage 4 in the Bray Group of the Leinster–Lakesman Terrane shows, in contrast, a distribution of both U–Pb ages and εHf values closely similar to those of the Gander Terrane in Newfoundland and other terranes attributed to Ganderia, interpreted to be derived from the margin of Amazonia. East Avalonia is clearly distinct from Ganderia, but shows evidence for older crustal components not present in West Avalonia of Newfoundland. These three components of the Appalachian–Caledonide Orogen came from distinct sources on the margin of Cambrian Gondwana.

Three surviving stone lecterns are described and analysed in terms of their petrography and sculptural style. The similarity between their petrography strongly suggests that they share a common origin, traceable to a quarry or quarries in the immediate vicinity of Much Wenlock, and that the similarity of sculptural style and dimensions points to them being a product of a single workshop. Furthermore, the authors suggest that the petrographie and stylistic characteristics show striking similarities to the Much Wenlock lavabo, thus adding support to the notion of a Much Wenlock workshop.

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