CAMPANIAN-MAASTRICHTIAN DEPOSITS IN THE FRONTAL PART OF THE OLYUTOR ZONE (SOUTHERN KORYAK UPLAND)

Abstract

New dating of volcanogenic-siliceous oceanic (marginal-sea) deposits of the frontal Olyutor zone correlative with rocks of the Vatyna Group indicates that, in addition to Albian-Campanian, they include the younger Campanian-Maastrichtian horizons. The data allow us to contend that the oceanic and/or marginal-sea (Vatyna) and island-arc (Achaivayam) deposits, also dating back to the Campanian-Maastrichtian, were in lateral connections at that time. On the other hand, the analysis of new and published data shows the Campanian-Maastrichtian island-arc deposits could probably overlap the pre-Campanian oceanic and/or marginal-sea sediments without any apparent disconformity.