Radiating rifts and dyke swarms of the middle Paleozoic Yakutsk plume of eastern Siberian craton

Abstract The eastern part of the Siberian craton is locus to a mid-Paleozoic large igneous province (LIP) distributed over an area of >0.7 × 10 6  km. This Yakutsk LIP originated from a mantle plume that caused early domal uplift, formation of ‘triple junction’ rifts (with uplift of their shoulders), associated mafic magmatism including volcanics, sills and a giant radiating dyke swarm, and associated diamondiferous kimberlites (Mirnyi, Nakyn and Dladyn-Alakit fields). The mafic magmas are dominantly tholeiites with patterns that are overall similar to ocean island basalts (OIB), and isotope geochemistry suggests a mixture of enriched and depleted sources. Geochemistry is consistent with plume-lithospheric interactions. The main axis of failed rifting along the E–W trending Vilyui rift represents reactivation of the Akitkan belt along which at 1.9 Ga was the proposed locus of collision between northern (Anabar) and southern (Aldan) superterranes, and subsequent aulacogen rifting in the Mesoproterozoic.