Author: Tomislav Baketarić, mag.geol.
In Croatian part of Pannonian Basin System (Mura and Drava depression), Late Miocene-Pliocene post-rift sediments (Pannonian stage) are represented by large complex prograding clinothem sets visible on seismic sections. Using seismic stratigraphy as a method in other parts of the PBS Magyar et al. (2006, 2007), Sztano et al. (2013), Balasz et al. (2017) and Sebe et al. (2020) concluded that the lacustrine infill of Upper Miocene sediments consists of prograding deltaic complexes characterized by clinoforms on seismic reflection data. The reconstruction of the gradual progradation, i.e. the infill of the basin in this part of the PBS in time and space, was done through the analysis of spatial and temporal variations of the clinoform geometry and the trajectories of the slopes. During interpretation of the clinoforms, determined by distinct seismic facies, the upper and lower edges of the slope (rollover boundaries) were mapped (sensu Patruno et al., 2015; Paumard et al., 2018). By applying seismic stratigraphy principles, as well as analyzing the movement of the slope and the rollover boundaries within the clinoforms, an insight into the spatial diachronous closure of Lake Pannon within these depressions was obtained. Throughout the area 15 regional clinothem surfaces were mapped (Pa-1 to Pa-15). Based on stratigraphic data linked with seismic relative chronostratigraphic framework of the Upper Miocene and Pliocene infill was built (Figure 1). Clinothems mapped over the area of two depressions spatially define the closure of Lake Pannon during the Late Miocene and the Early Pliocene through time. Although often aggravated by lack or poor quality of the data, such framework considerably improved reconstruction of paleogeographic evolution and sediment fairways.
Figure 1. Trajectories of the Lake Pannon delta front (upper rollover boundaries) connected by line) shown on present-day topography of the Pannonian Basin. Upper rollover trajectories of Mura and Drava Basins are based on this work, while geographical position of the trajectories in other parts of the PBS are correlated and connected based on Magyar et al.(2013) i Magyar (2021). Dominant progradation direction during Pannonian in Hrvatsko Zagorje basin are based on Kovačić et al. (2004). For reference, international borders are marked in orange, while the largest cities are marked with red dots.
Reference:
Patruno et al., 2015; Paumard et al., 2018
Balázs, A., Magyar, I., Matenco, L., Sztanó, O., Tokes, L., Horváth, F. (2017): Morphology of a large paleo-lake: Analysis of compaction in the Miocene-Quaternary Pannonian Basin. Global and Planetary Change. 171, 134-147, doi:10.1016/j.gloplacha.2017.10.012.
Kovačić, M., Zupanič, J., Babić, Lj, Vrsaljko, D., Miknić, M., Bakrač, K., Hećimović, I., Avanić,R., Brkić,M. (2004): Lacustrine basin todelta evolution in the Zagorje Basin, a Pannonian sub-basin (Late Miocene: Pontian, NW Croatia). Facies 50, 19–33.
Magyar, I., Fogarasi, A., Vakarcs, G., Bukó, L., Tari, G.C., (2006): The largest hydrocarbon field discovered to date in Hungary: Algyő. In: Golonka, J., Picha, F.J. (Eds.) The Carpathians and their foreland: geology and hydrocarbon resources. American Association of Petroleum Geologists, Memoir, 84, pp. 619–632, doi: 10.1306/985734M843142
Magyar, I., Lantos, M., Ujszászi, K., Kordos, L., (2007): Magnetostratigraphic, seismic and biostratigraphic correlations of the Upper Miocene sediments in the northwestern Pannonian Basin System. Geologica Carpathica, 58, 277–290.
Magyar, I., Radivojević, D., Sztanó, O., Synak, R., Ujszászi, K. Pócsik, M. (2013): Progradation of the paleo-Danube shelf margin across the Pannonian Basin during the Late Miocene and Early Pliocene. Global and Planetary Change, 103,168-173, doi:10.1016/j.gloplacha.2012.06.007.
Magyar I. (2021): Chronostratigraphy of clinothem-filled non-marine basins: Dating the Pannonian Stage. Global and Planetary Change, 205, 103609, doi:10.1016/j.gloplacha.2021.103609.
Patruno, S., Hampson, G. J., Jackson, C.A.L. (2015): Quantitative characterisation of deltaic and subaqueous clinoforms. Earth Science Reviews, 142, 79–119, doi:10.1016/j.earscirev.2015.01.004
Paumard, V., Bourget, J., Payenberg, T., Ainsworth, B., George, A.D., Lang, S., Posamentier, H.W., Peyrot, D. (2018): Controls on shelfmargin architecture and sediment partitioning during a syn-rift to post-rift transition: Insights from the Barrow Group (Northern Carnarvon Basin, North West Shelf, Australia). Earth-Science Reviews, 177, 643-677, doi:10.1016/j.earscirev.2017.11.026.
Sebe, K., Kovačić, M., Magyar, I., Krizmanić, K., Špelić, M., Bigunac, D., & Sütőné Szentai, M., Kovács, A., Korecz, A., Bakrač, K., Hajek Tadesse, V., Troskot-Čorbić, T., Sztanó, O. (2020): Correlation of upper Miocene-Pliocene Lake Pannon deposits across the Drava Basin, Croatia and Hungary. Geologia Croatica, 73, 177-195, doi:10.4154/gc.2020.12.
Sztanó O., Szafián P., Magyar I., Horányi A., Bada G., Hughes D.W., Hoyer D.L., Wallis R.J. (2013): Aggradation and progradation controlled clinothems and deep-water sand delivery model in the Neogene lake pannon, Makó Trough, Pannonian Basin, SE Hungary. Global Planet. Change, 103, 149-167, doi:10.1016/j.gloplacha.2012.05.026.
Tomislav Baketarić, mag.geol. is a geology PhD candidate at the Faculty of Mining, Geology and the Petroleum Engineering, University of Zagreb. He currently works at INA-Industrija Nafte d.d. as the Chief Expert for Geology and Geophysics within Exploration.