VAKARCS, GABOR, Rice Univ., Department of Geology and Geophysics, Houston, TX

ABSTRACT: Third-Order Sequences in the Neogene Synrift-Postrift Sedimentary Fill of the Pannonian Basin of Hungary

The Late Miocene-Pliocene sedimentary evolution of the transtensional Pannonian Basin (Hungary) was characterized by the advance of deltas from the northwestern, northern and northeastern basin margin. During the first stage (13.8 Ma-10.5 Ma) deltas prograded into a 100-400 m deep lake. From 10.5 Ma onward, as the result of the isolation of the Pannonian basin from the world sea, the water level increased to 800-1000 m (10.5 Ma-6.3 Ma). In the third stage (6.3 Ma-about 4.8 Ma) delta construction was again characterized by progradation in shallower water (200-400 m). Finally, the rate of sediment supply exceeded the rate of thermal subsidence, resulting in the complete infilling of the Pannonian Lake.

The non-marine post-rift sedimentary fill (<10.5 Ma) of the Pannonian basin consists of depositional sequences. The internal geometry and sedimentary facies of the systems tracts building up these sequences show the same characteristics as marine siliciclastic depositional sequences. The lacustrine sequences are apparently associated with major falls in the level of the Pannonian Lake and considered to be third-order sequences. Systematic sequence stratigraphic analysis has shown that in the syn-rift and post-rift sedimentary fill of the Pannonian basin twelve unconformities are correlated with the corresponding third-order late Miocene-Pliocene eustatic sea-level minima of the global eustatic curve.

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