Upper Cretaceous rhyolitic ash beds from the Novaya Sibir Island (New Siberian Islands)

Abstract

ABSTRACT Four separate rhyolitic ash layers (from 0.3 to 2.5 m in thickness) and dispersed fine-sized pyroclastic material were found for the first time within Turonian-Coniacian volcaniclastic–siliciclastic coal-bearing Derevyannye Gory Formation. It was concluded the terrigenous sedimentation in the studied area was affected by long-term explosive volcanic activity during Turonian-Coniacian, and centres of eruptions were located closely to modern Novaya Sibir Island territory. Pyroclastics under consideration are petrochemically similar to Lower Albian volcanic rocks from Anjou archipelago (Kotelny Island). The centres of long-time Early Albian to Turonian-Coniacian subaerial volcanism were located probably in the modern territories of Zemlya Bunge and Faddeya islands, and along the northern edge of the Sannikov Strait.