Rapid Sagging of the Barents Shelf over the Last 1516 ka

R. B. Krapivner

Hydrogeological and Geoecological Company (ZAO GIDEK), 15-aya Parkovaya ul. 10a, Moscow, 107203 Russia

e-mail: krapivner@hydec.ru

Received April 11, 2005

Abstract—A number of sedimentary sequences have been identified in the Barents shelf from investigations
of the upper part (100–150 m) of the geologic section, including sea drilling and continuous seismoacoustic
profiling. The uppermost sequence is represented mostly by clayey and silty–clayey material, which is consol-
idated only incipiently and therefore recognized easily in the seismic records. The sole of this sequence marks
an unconformity caused by a long period of a subaerial regime, fluvial drainage, and a break in sedimentation.
The timing of the last transgression is based on radiocarbon datings of foraminifers, mollusk shells, and other
organic remains from poorly consolidated sediments. This transgression was of a tectonic rather than a gla-
cioeustatic nature. The sagging proceeded with spatially varying amplitude and rate, and both parameters gen-
erally increased from the present-day shallow-water areas toward the deep sea, where the rate of subsidence
was 1.4–3.0 cm/yr, i.e., 1–2 orders of magnitude greater than the rate of sedimentation. These phenomena
explain why the subaerial landforms that preceded the last marine transgression are well preserved in deepwater
shelf areas. It is suggested that the sagging, which caused this transgression, was merely a particular stage of
oscillations of the western Arctic margin of Eurasia that lasted from the late Miocene to Quaternary and were
genetically or paragenetically related to the evolution of the Arctic oceanic basins.

DOI: 10.1134/S0016852106030046

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