Alkaline magmatism of the Chuktukon massif, Chadobets upland (Russia): sources, evolution of the magmas and their relation to the triassic Siberian lip

Abstract

The petrogenesis of temporal and spatially associated carbonatitic and deeply derived carbonated alkaline silicate magmas provides an opportunity to gain insights into the nature of the deepest lithospheric mantle. The Chuktukon massif, which is part of the Chadobets alkaline ultramafic carbonatite complex (Chadobets upland, Siberian craton) is a carbonatite-melilitite-aillikite intrusion, whose emplacement was coeval with Triassic volcanic-magmatic activity at the Siberian craton. In this study, we clarified the sources of the primary melts, reconstructed the magmatic evolution of the complex and discussed the relationship with the Siberian LIP Isotopic information leads us to propose that the source for the Chuktukon primary melts was isotopically depleted. We conclude that the primary melts were formed by low degree partial melting of long-lived garnet carbonated peridotite under the influence of heat from the plume. The major and trace element characteristics of the carbonatites are consistent with the formation of carbonatites by liquid immiscibility