A new 6 Myr stratigraphic framework for the Atlantic–Arctic Gateway

Abstract

A comprehensive stratigraphic framework for the Atlantic–Arctic Gateway has been established for the last 6 Myr on the Yermak Plateau, NW Svalbard, based on new paleomagnetic and biostratigraphic sampling and correlation of high-resolution seismic data between Ocean Drilling Program (ODP) Holes 911A, 910C and 912A. The new results indicate a Late Miocene age for the base of both Holes 911A and 910C, providing the first complete late Neogene record for the marginal Arctic Ocean and extending the previously published age model by several million years. During the late Miocene–Pleistocene, the southern Yermak Plateau was dominated by contourite deposition. From the intensification of the Northern Hemisphere glaciation at ∼2.7 Ma, glacial fans from NW Svalbard prograded onto the southernmost Yermak Plateau. This indicates that the ice sheet on NW Svalbard reached the shelf break at ∼2.7 Ma, much earlier than on the western Barents Sea–Svalbard margin (∼1.5 Ma). Simultaneous with the first shelf break glaciation on the western Barents Sea–Svalbard margin at ∼1.5 Ma, we observe the first signs of extensive glacial erosion on the Yermak Plateau, indicating a regional glacial intensification at this time for the whole Barents Sea-Svalbard region. Our results agree well with the widening/deepening of the Fram Strait and the opening of the Atlantic–Arctic Gateway during the middle Miocene.