| Abstract: | Studies in the Amundsen Basin have revealed six seismostratigraphic complexes (SSCs) in this region. The horizons bounding
these complexes were dated by identifying the linear magnetic anomalies. The recognized SSCs are correlated with the seismostratigraphic
and lithostratigraphic units of the Lomonosov Ridge. Based on these correlations, the lithological composition of SSCs in
the Amundsen Basin is suggested. The formation of SSC2 is supposed to be due to the diagenetic processes associated with the
transition of opal-A to opal-CT. It is found that, generally, the rate of sedimentation in the Amundsen Basin has consistently
decreased since the beginning of its formation. However, in the Chattian time, the global regression resulted in a sharp increase
in the rate of sedimentation in the basin. Arguments in favor of the duration of the Middle Cenozoic sedimentary hiatus on
the Lomonosov Ridge reduced to 16.3 Ma are presented. It is supposed that the decrease in the intensity of oceanic crustal
accretion in the Eurasian Basin, which is identified by the slowdown in the rate of its opening in the interval from 46 to
20–23 Ma might have resulted in a gradual sea level falling in the Arctic Ocean isolated from the World Ocean. This fact probably
accounts for the Lomonosov Ridge having remained in subaerial conditions over the period from 36.7 to 20.4 Ma. |
