Evidence for Partial Melting in Mantle Xenoliths of Spinel Lherzolites of Zhokhov Island, De Long Archipelago, Eastern Arctic

Zhokhov Island belongs to the De Long Archipelago located in the Eastern sector of the Russian continental shelf within the Arctic Basin. The island is a young volcanic center and is composed of lava flows of alkaline olivine-porphyry basalts and subordinate limburgites. The study was aimed at identifying the possible regional and geodynamic factors influencing the specifics of the partial melting and mineral transformations in mantle xenoliths of Zhokhov Island. Five xenoliths selected from alkali basalt samples on Zhokhov Island were studied using a scanning electron microscope. The data obtained allowed us to conclude that the formation of high-sodium glasses in the mantle xenoliths of Zhokhov Island is associated with the interaction between spinel lherzolites and parental melts of host olivine basalts. At the same time, high-potassium glasses inside mantle xenoliths were formed in situ during the melting of a primary potassium-bearing phase, likely phlogopite. The formation of two distinct compositionally contrasting recrystallization zones in contact between the mantle xenoliths and the host basalt is caused by the evolution of host alkaline silicate melt from sodic to potassic composition. Signs of activation of young intraplate magmatism that brought up the fragments of metasomatized shallow mantle to the surface are established over a large area of the Arctic Basin within the HALIP large igneous province.