The structure of the basin's slopes is interpreted as a huge flexure which has been developing throughout alI Cenozoic. The basin is filled with a thick series of Paleocene to Quaternary deposits without apparent signs of breaks. A thin but stratigraphically relatively complete column of Cenozoic marine deposits is determined above the slope brow on paleoshelves. So, in the mode of occurrence of any Cenozoic series taken separately, a flexure is distinctly outlined, its common limb coinciding with the slope of the basin. Within the dropped side of the flexure (in the basin), each series is several times thicker than the synchronogenic series within the upper side (on the shelf). At the slope of the basin, each series thins out reaching zero thicknesses at the limit. Narrow tortuous zones of no deposits shift upslope with rejuvenation of deposits and merge into a single variable-age unconformity surface appearing as a common surface at the seismic section. Such structure of the slopes points to their underwater consedimentational washout and to the existence of a deep-water basin throughout all Cenozoic era. There are observed numerous particular differences in the character of the slope, steps at various levels, numerous local breaks in thin strata above the slope brow, gradual transitions along the strike from steep areas of the slope to gentle sloping ones, thick clinoforms of paleodeltas and submarine fans.

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