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

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.

KEYWORDS:

• North-East Arctic
• New Siberian Islands
• Novaya Sibir Island
• Upper Cretaceous
• Turonian-Coniacian
• Derevyannye Gory Formation
• ash layers
• rhyolite explosive volcanism

Acknowledgments

We are indebted to Galina N. Aleksandrova and Alexey B. Herman for useful discussions on biostratigraphy of Cretaceous formations of the North-East Arctic Russia and New Siberian Islands. V. Kostyleva appreciates her colleagues Boris Golionko, Alexandr Basilian and Pavel Nikolski (GIN RAN) for taking part in field work. We thank Bernard Coackley for his helpful advice and improvements in English language, and anonymous reviewer for the useful recommendations. We are especially grateful to Solveig Estrada for careful reading of the manuscript, very constructive suggestions and providing valuable information that substantially improved the quality of this article.

Additional information

Funding

This study has been carried out following the plans of the scientific research of the Geological Institute of RAS (project no 0135-2019-0071). Field works and analytical studies were supported by “RN-Shelf-Arctic” Oil Company (2016-2017).