JELASKA, VLADIMIR, and IVAN GUSIC, University of Zagreb, Department of Geology and Paleontology, Zagreb, Croatia

Cretaceous Evolution of the Adriatic Carbonate Platform

The Upper Cretaceous sequence of the Adriatic platform mostly comprises small-scale shallowing-upward cycles which consist of an alternation of subtidal to intertidal to supratidal facies producing thick "layer-cake" column.

The sedimentary features of the Upper Cretaceous carbonates reflect direct connections with sea level fluctuations. Deposition during Upper Cretaceous took place in very shallow water where minor changes in sea level caused significant changes in environments. Therefore, relative sea-level changescan abruptly alter facies differentiation on the platform and cause advance or retreat of the margin. Moreover, carbonate platforms are extremely sensitive to local-to-regional tectonic effects. Due to their extent and duration, platform sequences record in detail the interaction of local sedimentation and tectonics with global changes in sea-level and climate over long periods. Therefore, the discrimination between extrinsic, global (eustatic) signals and intrinsic, local (tectonic) "noise" s of paramount importance. In that case the study of the Upper Cretaceous vertical sequence is of prime interest for understanding both the causality of minor sea level fluctuations to platform rhythmic succession, and global eustatic sea-level risings and their effects on the platform sedimentation.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.