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The overall architecture of a sedimentary basin is driven by a complex interplay between subsidence, waterlevel variations, and sediment influx rates. Several studies have been carried out in continental margin settings to analyse the effect of these forcing factors. However, in deep lacustrine settings, where temporally and laterally variable subsidence and uplift rates occur along with different climatic controls, and multiple sediment sources much less is known. Moreover, their distinct effects are usually overwritten by postsedimentary processes. Our main aim is to describe and discuss the influence of these internal and external forcing factors and demonstrate their sedimentary response, particularly the related unconformities and clinoform geometries in deep lacustrine settings. For this purpose, the DionisosFlow stratigraphic modelling software was used to carry out 3D numerical simulations. A series of numerical models were constrained and calibrated by observations from the southwestern margin of the Pannonian Basin of Central Europe. The results have implications on the local tectono-stratigraphic evolution. Our modelling infers that paleo-water depth could have been much larger than previously anticipated, reached 1300 m in the deepest part of the basin. Furthermore, we show that post-depositional processes, such as compaction and subsidence could create apparently descending shelf-edge trajectories and onlap surfaces, that are often misinterpreted as proofs of base-level drops. Therefore, we strengthen the argument that without restoring the original offlap geometry base-level drops higher than the seismic resolution cannot be identified and specifically did not occur in the area during the late Miocene. Modelling also infers that autoretreat and autocyclic variations are more effective at low sediment supply and higher amplitude lake-level variations. At locations of high sediment supply normal regression is continued, while between sediment entry points transgression occurs, highlighting that lateral variation needs to be considered during interpretation. Our numerical model is applicable to similar lacustrine sedimentary basins, but also provides insights to high-supply siliciclastic dominated marine shelf-margin systems.

A new stratigraphic standard for the open lacustrine to deltaic Pannonian Stage is emerging from the combined sedimentological, lithostratigraphical, sequence stratigraphical, biostratigraphical, seismic stratigraphical, geochronological, and magnetostratigraphical investigations of 6 long drill cores. These were drilled by Paks II Nuclear Power Plant Plc. as a preparatory step for the construction of a new power plant near the city of Paks, Central Pannonian Basin, between 2015 and 2016. The boreholes are in a distance of 8-12 km from each other, and five of them fully penetrated the local Pannonian sequence in a thickness of 390 to 662 m. Each core includes offshore clay marl deposited far from sediment entry points (Endrőd Fm), heterolithic, sandy siltstones of a

This study focuses on the appearance of two debated unconformities in the Drava Trough. In the Late Neogene lacustrine succession of the Pannonian Basin (PB) the so-called Pa-4 or “intra-Messinian” and the Miocene-Pliocene unconformities were recognized where gently folded lacustrine strata or steep portion of clinoforms are overlain by onlap surfaces. These two surfaces are often amalgamated which provides different interpretation possibilities. According to a group of researchers, the Pa-4 unconformity can be correlated basin-wide and is inferred to be linked with the major lake-level drop connected to the Messinian Salinity Crisis (MSC) or its triggers. In contrary others argue, that in the eastern part of the PB this geometry is a result of local interplay between structural inversion and the superposition of two different sediment feeder systems, in addition these events are older than the MSC. There is still no consensus about the nature and age of this surface. In the Drava Trough the succession covers the time interval of the MSC. The Miocene-Pliocene unconformity is clearly present, the Pa-4, however is indiscernible. Instead, features pointing to base-level rise are obvious. Our main goal is to analyze forcing factors controlling stratal geometries and to understand the rapid changes of the depositional environments. To this aim, 3D numerical simulations were performed by the DionisosFlow stratigraphic modeling software constrained by seismic and well data interpretation between the Mecsek mts (SW Hungary) and the Krndija mts (NE Croatia). Water depth evolution and 3D facies distribution of the basin has been simulated as well as the evolution of the main sedimentary transport routes. Model results are compared and validated by field observations from the margin of the Krndija mts. A pronounced angular unconformity could be studied in details within the Late Miocene lacustrine succession, between profundal calcareous marls and shallow water deltaic clay and sand beds. The unconformity is a hardground, below an age of 10.2-9.6 Ma and above younger than 6 Ma is indicated by mollusk shell-beds.Our numerical simulation yields new insights in quantifying the tectonic and climatic controls on the effects of the MSC in the Pannonian Basin. This presentation was supported by MOL Academic Aid Program, NKFIH 116618 and TÉT_16-1-2016- 0004.Our numerical simulation yields new insights in quantifying the tectonic and climatic controls on the effects of the MSC in the Pannonian Basin. This presentation was supported by MOL Academic Aid Program, NKFIH 116618 and TÉT_16-1-2016- 0004.

This study focuses on the so-called Pa(n)-4 sequence boundary or intra-Messinian unconformity and its appearance in the Drava Trough. A surface with similar geometric relations, i.e. folded/tilted lacustrine beds overlain by onlaps, can be observed in many places over the Pannonian Basin (PB). The regional nature of this surface led to the conclusion that it can be correlated basin-wide and it is a result of a major lake-level drop related to the Messinian Salinity Crisis (MSC) even though the Lake Pannon had no direct connection to the Mediterranian Sea. In contrast others argue, studying this feature in the eastern part of the PB, that a local interplay of structural events and the superposition of two different sediment feeder systems may have caused the observed geometry. There is still no consensus about the nature or the age of this surface. Prior to the events leading to the formation of this unconformity a significant flooding event took place. Stratal stacking is remarkably different in the Drava Trough compared to the one of the Eastern PB, though large thickness of shallow-water deposits is a common feature. The main goal of this study is to analyze factors controlling stratal geometries and to understand what change of the depositional environments occurred in relation with the above described events. The DionisosFlow stratigraphic modeling software was used constrained by seismic stratigraphy to reveal interactions of controlling factors. The extent of the Pa(n)-4 was traced in 2D seismic sections from the Mecsek Mts. (SW Hungary) to the Papuk Mts. (N Croatia). The model takes into account numerous factors such as sediment supply, tectonic uplift or subsidence rate. With the backstripping method three different scenarios were modeled: a) structural, b) climatic and c) sediment-supply controlled versions. By modifying input parameters, different effects became dominant and the variations in stratal geometries were analyzed. In addition, field observations from the margin of the Papuk Mts. helped to identify similar events in outcrops. A Late Miocene angular unconformity could be studied within the lacustrine succession, between profundal calcareous marls and shallow- water deltaic sands and clays. The hypothesis was tested favoring basin inversion and other factors rather than a major lake-level fall causing the prominent unconformity, with the onlap geometry. Results of the modeling are relevant to the expression of the MSC in the Pannonian Basin. This presentation was supported by MOL Academic Aid Program and NKFIH 116618.

Lake Pannon was filled by rapid sedimentation during the Late Miocene to Pliocene. The initially vast and deep lake was finally infilled by large sediment input, sig- nificantly exceeding the creation of accommodation space. Despite various sedimentological, paleontological and seis-mic stratigraphy-related research, there is still little know-ledge about different factors that were shaping the geome-try of this basin infill. These uncertainties can be resolved by an integrated study of the clinoforms system. More precisely, it can help in better understanding of the inter-play between shelf- edge trajectory, direction of sedimentary transport, spatial distribution of paleoenvironments, and basin morphology (paleobatimetry) combined with local tectonic events (TOMLJENOVIĆ & CSONTOS, 2001).The study is situated in the Eastern part of the Drava basin, in the area between Slatina and Valpovo. Numerous seismic horizons, mapped on 3D seismic data, were used for the construction of structural and thickness maps in the time domain. Seismic attributes, like RMS amplitude and spectral decomposition, were applied on the data as well. For the purpose of well to seismic ties, VSP and checkshots data were used. Geological age estimation of seismically defined and mapped horizons is based on existing stratigraphic logs from deep wells in the area. Some of these data are old. Based on seismic facies, two generations of clinoforms can be distinguished, a thicker older, and a thinner younger set. The first set is composed of 255 ms high sigmoidal cli- noforms in the western area, indicating a water depth of ca. 610 m. During their deposition, the shelf- margin trajectory was flat, until maximum regression was reached. Then, the second generation of clinoforms appears, showing oblique shape in the west, with downlap features to the east. Their height is increasing in the same direction, where clinoforms start to develop sigmoidal architecture, like in the older thicker set, with an interpreted depth of water column of ca. 190 m to 270 m.Seismic sections, structural, thickness and seismic at-tributes maps, show that delta progradation happened be- fore or during the initiation of basin inversion in this area (BALÁZS et al., 2016 ; SAFTIĆ et al., 2003). Prograding slope reached this area between 6.8 Ma and 5.3. Ma ago, and then, during the inversion, the whole studied sequence was tilted to the southwest. Observations confirmed that delta progradation occurred from the present day northwest and continued to the southeast. Distributary channels and basin floor lobes orientation are indicating that sedimentary input patterns may be gently influenced by inherited structures. Furthermore, different stratal stacking patterns are revealing lacustrine base level fluctuations. The flat trajectory of first clinoform progradation suggests steady base level, which continued to maximum regression, when the slope related canyons also developed (SZTANÓ et al., 2013). This event was followed by base level rise of more than 200 m. As a re- sult, the second generation of smaller clinoforms prograded on the new shelf and over the old slope. Similar events of base-level rise are common in Lake Pannon, nearby in the northern part of the Drava basin (UHRIN & SZTANÓ, 2012), yet far less than 100 m (SZTANÓ et al., 2013 ; BALÁZS et al., 2018), while much larger in the Eastern part of the Great Plain. Moreover, infilling patterns were probably influenced by local structures and basin topogra-phy, possibly connected to the large- scale tectonic events in this marginal part of Pannonian basin system.Despite many similar studies were done inside the in-dustry (IVKOVIĆ, 2000), this is the first published seis-mic study with focus on timing and factors controlling the morphological shelf-slope progradation, in the south-western part of the Pannonian basin system. Results are showing complex infilling patterns and changing base level throughout the time of progradation. Therefore, dating and palynological studies on well and outcrop data, will play a crucial role in solving the distribution of different paleoen-vironments through space and time, thus confirming the interpretation of depositional system that is in such a way manifested on seismic data.

The vast and deep Lake Pannon has been gradually filled in during the Late Miocene to Pliocene. Driving mechanism was large sediment input, exceeding creation of accommodation, and manifested by the large-scale clinoforms of shelf-margin progradation. Despite various studies by means of seismic stratigraphy, sedimentology and palaeontology, factors controlling basins fill architecture in various parts of Pannonian basin system are still controversial. The study of the clinoform succession, the shelf-edge trajectory in particular provides understanding of base- level variations, local structural movements and the spatial distribution of paleoenvironments.The study area is situated in Eastern part of the Drava basin. 3D seismic cubes were analysed in the time domain, covering the mapped area of more than 140 km. Standard procedures – well to seismic tie via VSP and checkshots data ; stratigraphic reports ; seismic stratigraphy techniques – were used, time-structure and RMS amplitude maps were constructed. Numerous horizons were mapped, from which two generations of clinoforms can be distinguished: a large and a small set. The first generation consists of sigmoidal clinoforms, indicating a water depth of ca. 610 m. The shelf-margin trajectory is flat until maximum regression was reached. The second generation is of small oblique ones pointing to a depth of ca. 190 m. These downlap on the old ones, but gradually their height is increasing as overtaking the old ones with parallel development of a sigmoidal geometry.The prograding slope reached the area after 6.8 Ma, but before the start of basin inversion at about 5.3 Ma ago, so no major structural complication is expected. Stratal stacking patterns and the shelf-margin trajectory reveal changes of lacustrine base-level. A clinoform progradation with flat trajectory to maximum regression points to steady base level. Afterwards flooding occurred with a base level rise of 200 m. This event generated accommodation for the smaller set of clinoforms, which continued progradation during the next period of steady base level. In Lake Pannon similar events of base-level rise are common, yet usually far less than 100 m. Seismic-scale deltaic clinoforms in the topsets of shelf-margin clinoforms were described only from a few other locations.This is the first detailed seismic study to document shelf-slope progradation in the SW part of the Pannonian basin system. Moreover, it is suggesting that, steady and rising base level were alternating during the progradation, but in this case, a higher than usual rise is documented. The Croatian Hydrocarbon Agency and Ministry of Economy, Entrepreneurship and Crafts provided data. Cooperation was supported via Hungarian- Croatian bilateral project (Stratigraphy and correlation of Upper Miocene-Pliocene sediments along the Croatian-Hungarian border and TÉT_16- 1- 2016-0004), the TEMPUS Foundation and Hungarian NKFI 116618. The academic license of Petrel Schlumberger is also acknowledged.

Dating of upper Miocene sediments of the Pannonian Basin (Hungary) has proven difficult due to the endemic nature of biota, scarcity of reliable radio isotopic data, and generally inconsistent magnetostratigraphic results. The natural remanent magnetization (NRM) is mostly residing in greigite (Fe3S4), which complicates NRM interpretation. We reinvestigate the viability of these sediments for magnetostratigraphy using samples from recently drilled well cores (PAET-30 and PAET-34) from the Paks region. Significant intervals of the cores contain composite NRM behavior. Thermal demagnetization results include multipolarity (M-type) samples consisting of a low-temperature (LT, above ~120 °C), a medium-temperature (MT), and a high-temperature (HT) component, within distinct temperature ranges and all exhibiting dual polarities. The LT and HT components have the same polarity and are antiparallel to the MT component. Rock magnetic and scanning electron microscopy results indicate that all magnetic components reside in authigenic greigite. The LT and HT components represent the characteristic remanent magnetization and are of early diagenetic origin. The MT component records a late diagenetic overprint. Alternating field demagnetization cannot resolve the individual components: it yields polarities corresponding to the dominant component resulting in erratic polarity patterns. Interpretation of LT and HT components allows a reasonably robust magnetostratigraphic correlation to the geomagnetic polarity time scale with the base of PAET-30 at ~8.4 Ma and its top at ~6.8 Ma (average sedimentation rate of ~30 cm/kyr). The base of PAET-34 is correlated to ~9 Ma and its top to ~6.8 Ma (average sedimentation rate of 27 cm/kyr).

The tectono-sedimentary evolution of asymmetric extensional systems driven by the activity of major normal faults or detachments associated with footwall exhumation is often characterized by a sequence of slower, faster, and ultimately again slower subsidence rates in the center of hanging wall half-grabens during their synkinematic and postkinematic evolution. We have studied this specific evolution by the means of 3-D stratigraphic numerical modeling that accounts for the variability of the sediment and water flux combined with climatic and sea level variations, and sediment compaction. The model setup is constrained by observations from the Pannonian back-arc basin of central Europe. Our modeling predicts the formation of low-order tectonic and higher-order sea level and climate-driven transgressive-regressive sedimentary cycles. Furthermore, we model and analyze the autocyclic nature of the depositional systems. Retrograding-prograding cycles are visible on the proximal flank of the half-grabens by their different spatial and temporal expressions, while depocenters record large water depth variations linked to the specific and episodic activity of normal faults and their migration with time. The application to a system of multiple half-grabens in the Pannonian Basin, which are activated in different locations, at different times and with different kinematics, demonstrates a complex interplay between direct sediment sourcing and the sediments' ability to bypass trapping subbasins and paleo-reliefs created by eroded footwalls.