The messinian problem in the pannonian basin, eastern Hungary - Insights from stratigraphic simulations

Earlier studies revealed a prominent unconformity in the Messinian stratigraphic record of the lacustrine Pannonian Basin, but it was unclear what factors were responsible for the formation of this unconformity, and thus its origin remained controversial. The problem was further complicated by the fact that stratal patterns in the Messinian varied significantly along the paleo-margins of the lake. Our study introduces quantitative stratigraphic simulations to analyze the role of subsidence, sediment supply, and lake-level changes in the formation of the unconformity and the various architectural patterns that evolved in response to the Messinian events. The results suggest that a relative lake-level fall occurred in the Messinian, accompanied and followed by tectonic inversion in several parts of the basin. Since the rate of tectonic subsidence and/or uplift varied in space and time, the size of the relative lake-level fall varied significantly across the basin, while various strata architectural patterns formed in the same time interval. The age of the unconformity was estimated, based on seismic correlations with paleomagnetic chronozones, to be between 5-6 Ma, which was refined by stratigraphic simulations. Galeacysta etrusca cysts were found in the unconformity, which confirmed its late Messinian age. The surface is called the Intra-Messinian Unconformity (IMU) in this paper. Seismic interpretations and simulations of stratal architecture led to the formulation of a basin fill model and identification of four stratigraphic architectural patterns related to Messinian events including a major lake-level fall and coeval and subsequent uplift events in certain parts of the basin. (C) 2007 Elsevier B.V. All rights reserved.