Offshore-Shoreface/Delta Transition in the Burbigalian Deposits from Bending Area of Eastern Carpathians

The determination of depositional systems in the Burdigalian sequences of outer napes from east Carpathians was done by applying the principles and algorithm of facies analysis . The deposits studied consist of shales, with thin sandstone intercalations and thicker sandstone deposits. Evaporitic deposits, represented by gypsum lamina are associated with shale deposits. We have separated eight different types of facies using petrographic, granulometric and structural criteria. They form a coarsening up sequence with a repetitive character. At the base, the sequence starts with marine deposits, and even restrictive offshore sedimentary environment, then we can observe the transition to shoreface deposits or possibly sandy deltaic deposits. The sand deposits preserve a very good evidence of fair and storm weather waves. The sedimentary rate was higher, thus water escape structures are found in the outcrops. The studied deposits could be the expression of the progradations and retrogradations of the facies, but the control factors are still opened for debate. Keeping into account the folding which affected the area, we believe that the tectonic influence primed over the eustatic changes.