Stratigraphical Correlation of the Barremian-Aptian Sedimentary Sequences of the Okriba-Khreiti and Dzirula Tectonic Subzones (Georgia)

The question of correlation of the Barremian-Aptian (Lower Cretaceous) sedimentary sequences, represented in the Okriba-Khreiti and its adjacent Dzirula tectonic subzones (Georgia), is studied. Selection of the considered territory as object for sequence stratigraphic correlation was conditioned by facial variety, existence of rich fossil composition and frequent alternation of sedimentation cycles during the Barremian-Aptian. On the basis of studying of unconformable surfaces, as well as of alternation of the comparatively deep and shallow sea facies of the Barremian-Aptian of the Dzirula subzone 5 sedimentary sequences (Br 1 1 -Br 1 3 , Br 2 1 -A 1 1 , A 1 2 -A 1 4 , A 2 1 -A 2 2 , A 3 1 -Al 1 1 ), corresponding to those established earlier in Okriba-Khreiti subzone, are revealed. Biostratigraphic frames of these sequences are specified, as well as their variable litho- and biofacial features in time and space are analysed. In most cases sequence boundaries are characterized by erosion surfaces, but in those sections where sequences represent comparatively deeper shelf setting facies, sequence boundaries are conformable. In all cases when boundaries between two sequences are represented by stratigraphical gap, beds of adjacent sequences are characterized by same dip azimuth and dip angle. Accordingly, each such boundary represents typical disconformity and the chronostratigraphic range of its degradation vacuity is variable in the considered region. © 2013 Bull. Georg. Natl. Acad. Sci.