New Age Data on the Volcanic Rocks of the Alazey Plateau (Northeastern Yakutia)

Resumo

The age of the rocks of the Cretaceous volcanogenic sequence of the Alazey Plateau, Kolyma–Indigirka Orogen of Northeastern Russia, is determined using U–Pb zircon dating on trachydacites and K–Ar feldspar–groundmass dating on dacites and basalts. The dacites of the Severnaya Sededema Formation, which was formed within volcanic belts, are dated as Aptian–Cenomanian (106–97 Ma), while the basalts of the Khangatas Formation yield the Paleocene age (59 Ma). These rocks mark the extension and rifting stage in the evolution of the region.