Caledonian hot zone magmatism in the ‘Newer Granites’: insight from the Cluanie and Clunes plutons, Northern Scottish Highlands

Scottish ‘Newer Granites’ record the evolution of Caledonides resulting from Iapetus subduction and slab breakoff during Silurian–Devonian Scandian Orogeny, but relationships between geodynamics, petrogenesis emplacement are incomplete. Laser ablation U–Pb results magmatic zircons at Cluanie Pluton (Northern Highlands) identify clusters concordant Silurian data points. A cluster with a weighted mean 206 Pb/ 238 U age 431.6 ± 1.3 Ma (2 σ confidence interval, n = 6) records whilst older points (clustered 441.8 2.3 Ma, 9) deep crustal hot zone magmatism prior to ascent. The Pluton, its neighbour c. 428 Clunes tonalite, have adakite-like high Na, Sr/Y, La/Yb low Mg, Ni Cr characteristics, lack mafic facies common in other Granites’. These geochemical signatures indicate tapping batches homogenized, evolved magma deeper crust. confirms volumetrically modest subduction-related occurred beneath Northern Highlands before breakoff, probably restricted by thickening 450 Grampian 2 event. Extensive new situ geochemical–geochronological studies for this terrane may further substantiate model association Caledonian potentially metallogenesis. term is outdated as it ignores geochronology, petrography tectonic setting. Hence, ‘Caledonian intrusions’ would be more appropriate generic cover those bodies related either or breakoff. Supplementary material: Full geochronological, whole rock geobarometric available https://doi.org/10.6084/m9.figshare.c.6305927