The Main Stages of Formation of the Fram Strait in the Neogene: Analysis of Geological and Geophysical Data

The opening of the Fram Strait began in the Lower Miocene (~19.5 Ma) as a result of movements of the North American and Eurasian plates, which resulted in the formation of the narrowest segment of the strait, the Lena Trough. In the Early and Late Miocene (~19.5–9.8 Ma), the opening of the central part of the Fram Strait led to the formation of the central and northwestern parts of the Molloy Basin, which had an extended basement consisting of blocks of the West Spitsbergen fold-and-thrust belt. In the Late Miocene (~9.8 Ma), in the central part of the Fram Strait, a jump of its opening axis to the east occurred in the segments between the Molloy and Spitsbergen fracture zones, and spreading began in the northernmost segment of the Knipovich Ridge. In the Late Miocene (~9.8 Ma), deep-sea exchange of waters between the North Atlantic and the Arctic Ocean took place west of continental “fragments” of the Barents Sea: the Hovgaard Ridge and Mt. Hovgaard. In the Late Miocene (~6.7 Ma), the Molloy Basin began to open, which coincides with the beginning of continuous subsidence of the Hovgaard Ridge, which was in subaerial conditions, and with a threefold increase in the sedimentation rate in the central Molloy Basin. In the Late Miocene‒Early Pleistocene (~9.8‒1.8 Ma), a warm current from the North Atlantic could have passed along the eastern continental margin of Greenland and, at the peak of its maximum intensity, ensured the existence of biological diversity in the “polar desert” and “polar night” conditions in north‒northeast Greenland and the shallow sea areas adjacent to the coast. The modern direction of cold and warm currents in the Fram Strait could have formed in the Early Pleistocene (~1.8 Ma) and may be associated with opening of the northernmost segment of the Knipovich Ridge.