Hydromagmatophile and rare earth elements in the Cretaceous-Paleogene basaltoids of the Verkhnyaya Kolyma megadome

The chemical composition of the Cretaceous-Paleogene bimodal trachyrhyolite -basaltic association has been studied in the southwestern portion of the V erkhnyaya Kolyma megadome. The first data have been presented on the concen trations of REE, Nb, and other elements in the subalkaline basaltoids of th e Magadan region. The higher P, Ti, and Zr contents in these rocks as compa red to andesite rock associations of the Okhotsk-Chukotka volcanogenic belt indicate a deep mantle origin of the parental alkaline picrite melts. Stro ntium isotopic data suggest that acid volcanics of the studied bimodal asso ciation were derived through crustal melting under the action of basaltic m agma heat.