Dr Orsolya Sztanó
@elte.hu
Associate Professor, Department of Physical and Applied Geology
Eotvos Lorand University, Budapest
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Hana Ben Mahrez, Patrícia Márton, Béla Márton, Judit Mádl Szőnyi, József Kovács, and Orsolya Sztanó
Elsevier BV
Fanni Szabó, Orsolya Sztanó, and Krisztina Sebe
Foldtani Kozlony
A Mecsektől nyugatra eső dél-zselici terület geológiai felépítéséről viszonylag keveset tudunk, pedig kulcsfontosságú terület, hiszen a mélyföldtani adatok és a feltárások alapján össze tudnánk kapcsolni a Mecsek és a Dráva-medence pannon-tavi üledékképződési környezeteit.
 Ebben a tanulmányban elvégeztük három Mecsek környéki, kevésbé ismert neogén rétegsor elemzését, ahol a tavi üledékek a felszínre bukkannak. Felhagyott homokbányákban tettünk terepi megfigyeléseket Szigetvár környékén, majd fácieselemzést végeztünk: nyolc fáciesegységet és négy fáciesegyüttest különítettünk el. A fáciesegyüttesek alapján elkülönítettünk deltamedrekben (CH), deltaág-elvégződésekben (TDC), torkolati zátonyokon (MB) és nyíltvízben (FF) zajló üledékképződést. Megállapítottuk, hogy három fő üledékképződési folyamat volt hatással a vizsgált rétegsorok képződésére. Ezek a delta síkságon lévő eltérő méretű medrekben zajló üledékképződés, a völgybevágódások kialakulása, valamint egy vízszintemelkedés hatására bekövetkező elöntés. A homokos, mederkitöltő egységekben két különböző mederméretet határoztunk meg. A nagyobbak deltaágak, míg a kisebbek deltaág-elvégződések és azokhoz kapcsolódó torkolati zátonyok. Az agyagos összlet kimélyülés hatására alakult ki a hullámzás által legyalult elöntési felszín felett. Az őskörnyezeti rekonstrukció arra mutat, hogy az összes feltárás rétegsora egy többszintű, összetett völgykitöltés során keletkezett. A völgybevágódást egy 15-20 méteres vízszintesés hozta létre, amely fokozatosan feltöltődött a vízszint emelkedésének ütemében. Ezekre a völgykitöltő üledékekre települ a fedő agyagos rész, amely mindegyik feltárásban hasonlóan jelenik meg, és egy elöntési esemény hatására jött létre. A vizsgált feltárásokban két fő szállítási irányt állapítottunk meg. Az egyik DDK-i, amely a völgybevágódás irányát mutatja és megegyezik a Pannon-tó selfperemének a területen megállapított épülési irányával. A másik NyDNy-i, amely a mellékvölgy alárendeltsége miatt eltérő a jellemző szállítási iránytól. A Pannon-tóból már ismert völgykitöltéseket összevetve a dél-zselici területen létrejött völgybevágódással megállapítottuk, hogy ezek egy, vagy akár több 15-20 méteres vízszintesési esemény hatására alakulhattak ki, melyek jellemzőek voltak a Pannon-tóra. Eredményeink hozzájárulnak a völgybevágódások, deltaág-elvégződések, torkolati zátonyok és tavi környezetben létrejött delták megismeréséhez, valamint a tavi vízszintváltozások hatásainak vizsgálatához.
Marko Špelić, Ádám Kovács, Bruno Saftić, and Orsolya Sztanó
Springer Science and Business Media LLC
AbstractThe thick Lake Pannon sedimentary record provides insights into the downdip and lateral development of stratigraphic surfaces through the analysis of the basin-scale clinoform progradation. The clinoform architecture from the eastern part of the Drava Basin (Pannonian Basin System) was interpreted to reflect the base-level changes. A major downlap surface interpreted as a flooding event followed by rejuvenation of slope progradation was recognized on 2D seismic sections. Detailed 3D seismic interpretation combined with well data revealed that the large sigmoidal and the overlying small oblique clinoform sets that downlap the large one only apparently produce the geometry of a maximum flooding surface. Instead, the 3D mapping revealed the influence of two competing slope systems arriving from the north and northwest. Lateral switching of sediment input, similar to many recent deltaic systems. e.g., Danube and Po rivers led to the variability of stratigraphic surfaces, lithology, and thickness, which resulted in non-uniform shelf-edge migration. These observations were supported by forward stratigraphic modeling simulating different scenarios, which led to the generation of the depositional architecture with an apparent maximum flooding surface. This study also implies the potential pitfalls in basin analysis based only on scarce 2D seismic and emphasizes the role of lateral variations in sediment input controlling the depositional architecture.
István Róbert Bartha, D. Botka, Vivien Csoma, L. Katona, E. Tóth, I. Magyar, Lóránd Silye and O. Sztanó
Sedimentary successions exposed at basin margins as a result of late-stage inversion, uplift and erosion usually represent only a limited portion of the entire basin fill; thus, they are highly incomplete records of basin evolution. Small satellite basins, however, might have the potential of recording more complete histories. The late Miocene sedimentary history of the Șimleu Basin, a north-eastern satellite of the vast Pannonian Basin, was investigated through the study of large outcrops and correlative well-logs. A full transgressive–regressive cycle is reconstructed, which formed within a ca. 1 million-year time frame (10.6–9.6 Ma). The transgressive phase is represented by coarse-grained deltas overlain by deep-water lacustrine marls. Onset of the regressive phase is indicated by sandy turbidite lobes and channels, followed by slope shales, and topped by stacked deltaic lobes and fluvial deposits. The deep- to shallow-water sedimentary facies are similar to those deposited in the central, deep part of the Pannonian Basin. The Șimleu Basin is thus a close and almost complete outcrop analogue of the Pannonian Basin’s lacustrine sedimentary record known mainly from subsurface data, such as well-logs, cores and seismic sections from the basin interior. This study demonstrates that deposits of small satellite basins may reflect the whole sequence of processes that shaped the major basin, although at a smaller spatial and temporal scale.
Vivien Csoma, Imre Magyar, Andrea Szuromi-Korecz, Krisztina Sebe, Orsolya Sztanó, Krisztina Buczkó, and Emőke Tóth
Foldtani Kozlony
The large outcrop at Pécs-Danitzpuszta, southern Hungary, exposes a 65-meter-thick succession of calcareous marls, clay marls and calcareous sands that were deposited during the early history of Lake Pannon, a vast, Caspian-type lake in Central Europe in the late Miocene. Within the framework of the complex stratigraphic investigation of this succession, well preserved, relatively diverse benthic ostracod assemblages containing 39 taxa were recovered from 29 samples (16 samples were barren). Palaeoecological interpretation of the ostracod genera suggests that deposition took place in a low-energy environment, in the shallow sublittoral zone of Lake Pannon, in pliohaline (9–16‰ salinity) water. The entire succession was divided into four interval zones based on the first occurrences of assumedly useful marker fossils: Hemicytheria lorentheyi Zone (from sample D29), Hemicytheria tenuistriata Zone (from sample D17), Propontoniella candeo Zone (from sample D115) and Amplocypris abscissa Zone (from sample D209). Based on comparison to the Beočin section 150 km to the SE, where a lithologically and stratigraphically similar section was dated magnetostratigraphically by an international team, we tentatively assume that the Pannonian marl succession of the Pécs-Danitzpuszta outcrop represents the time interval of 11.6 to ca. 10 Ma.
Krisztina Sebe, G. Konrád and O. Sztanó
The Pécs-Danitzpuszta sand pit is the most important outcrop of the oldest Pannonian (upper Miocene, Tortonian) deposits in southern Hungary. A trench excavated in 2018 exposed Lake Pannon deposits and underlying Paratethys strata down to the upper Badenian (Serravallian), and together with the sand pit they make up a continuous sedimentary succession with a true thickness of ~220 metres. Due to tectonic deformation, middle Miocene deposits and carbonates in the lowermost Pannonian are overturned. Layers become vertical close to the marl-sand boundary, then the dip changes to normal, with continuously decreasing dip angles. The exposed succession starts with 5 m of upper Badenian (13.8-12.6 Ma old) calcareous marls and sandy limestones with sublittoral, then littoral molluscs, which were deposited in the normal salinity seawaters of the Central Paratethys. The overlying 8 m of sand, silt, sandy breccia and conglomerate are fossil-free,; only the lowermost silt layer contains reworked Badenian microfauna. This unit probably accumulated from gravity-driven flows in a fan-like, probably terrestrial depositional setting. The next 7.5 m of frequently alternating thin-bedded limestones, marls and clays with sublittoral biota represent rapid transgression. Foraminifers, ostracods, molluscs and calcareous nannoplankton indicate late Sarmatian, then Pannonian age for this interval. However, the locations of the boundaries indicated by the various groups are not are not consistent, making the position of the Sarmatian/Pannonian boundary uncertain. The Sarmatian beds with marine fossils still accumulated in the Paratethys, between ~12.1–11.6 Ma, under varying salinities due among others to temporary freshwater input. The Pannonian strata already represent sediments of the brackish Lake Pannon. Above these beds, uniform calcareous marl becomes dominant with some clay layers and graded or structureless conglomerate to sandstone interbeds. The deposition of the overall 64- m- thick Pannonian calcareous marl section took place in the open, probably few -hundred -metres -deep water of the lake between ~11.62 and 10.5–10.2 Ma. It may represent a rare, well-exposed surface occurrence of the Endrőd Formation which is known from thousands of wells in the Pannonian Basin. Above this section, a 6-7 -m- thick transitional interval of silty marls and sands is followed by ~140 m of limonitic, pebbly sands. They have poor to moderate sorting and rounding, metre -thick beds with transitional boundaries and abundant fossils and clasts reworked from older Miocene units. Their accumulation took place between 10.2-10.5 and 9.6 Ma by gravity flows connected to deep-water portions of fan deltas.
Lilla Tőkés, István Róbert Bartha, Lóránd Silye, Csaba Krézsek, and Orsolya Sztanó
Elsevier BV
Ádám Kovács, Attila Balázs, Marko Špelić, and Orsolya Sztanó
Elsevier BV
Attila Balázs, Liviu Maţenco, Didier Granjeon, Katharina Alms, Thomas François, and Orsolya Sztanó
Elsevier BV
Abstract Subsidence and uplift patterns and thermal history of sedimentary basins are controlled by tectonics, mantle dynamics and surface processes, such as erosion, sediment transport and deposition and their links to climatic variations. We use combined thermo-mechanical and stratigraphic numerical modelling techniques to quantify the links between tectonic and surface processes. We aim to assess the thermal evolution and subsidence rates of asymmetric extensional basins during the syn- and post-rift times by simulating different erosion and sedimentation rates. We analyse the 3D sedimentary architecture and facies distribution of the depocenters. Model results are validated by observations in the Pannonian Basin of Central Europe. Extensional reactivation of inherited suture zones creates asymmetric basin systems controlled by large-scale detachments or low-angle normal faults, where crustal and lithospheric mantle thinning are often rheologically decoupled. Subsidence rates and basement heat flow in the depocenters show large variabilities during asymmetric extension and post-rift evolution controlled by their initial position from the suture zone and migration of deformation. Transient heat flow anomalies mirror crustal exhumation of footwalls, sediment blanketing and erosion effects in the basins. Enhanced erosion and sedimentation facilitate lower crustal deformation and elastic flexure of the weak, extended lithosphere leading to accentuated differential uplift and subsidence during the syn- and post-rift basin evolution. Tectonics, climate and autogenic processes control transgressive-regressive cycles at different timescales together with the overall sedimentary facies distribution. In our models assuming wet climate the high subsidence rate often outpaces moments of eustatic water-level fall preventing relative base-level fall and enhances the effects of autogenic processes, such as lobe switching processes.
Ádám Kovács, Attila Balázs, Marko Špelić, and Orsolya Sztanó
Elsevier BV
Abstract The overall geometry of sedimentary basins is driven by a complex interplay between subsidence, water-level variations, sedimentation rates and basin-margin topography. Seaward movement of the shoreline is driven by either high sediment input or by base-level drop. The influence of the specific driving mechanisms is often overwritten by subsequent burial and compaction effects or it is below the resolution of observational data. 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 a deep lacustrine setting. To this aim, 3D numerical simulations were performed using DionisosFlow stratigraphic forward modeling software. Models are constrained by seismic and well data from the Drava Basin part of the SW Pannonian Basin, Central Europe. A wide range of parameters, such as subsidence rates, lake-level curves and sedimentation rates were compared and analyzed. Post-rift subsidence and inversion of the basin have been simulated together with the main sedimentary transport routes. Our calculation infers that paleo-water depth could have reached ca. 1300 m in the deepest parts of the basin. Furthermore, our models show that differential compaction, subsidence and lateral variations of the sediment supply result in apparently descending shelf edge trajectories and onlapping clinoform surfaces that are often misinterpreted as base-level drops. By analyzing the sedimentary response to different climatic variations, we argue that there is no direct indication of a major base-level drop in the Drava Basin, which was much larger than the seismic resolution, i.e. 40–50 m. Modeling also infers that autoretreat and autocyclic variations are more effective at low sediment supply and higher amplitude lake-level variations.
Orsolya Sztanó, Soma Budai, Imre Magyar, Gábor Csillag, Judit Nadrai, and László Fodor
Elsevier BV
Abstract Gravelly tsunami event beds are well known from some contemporary shores, but they are far less known from the pre-Quaternary depositional record. Lacustrine examples are particularly exceptional. Here we present multidisciplinary evidence for a lacustrine cobble to boulder gravel deposited as an onshore paleo-tsunamiite and discuss features that help to identify the depositional setting. The deposit was formed on the rocky shore of a large peninsula within the late Miocene Lake Pannon (Hungary). The lake was several hundred meters deep, and near to the study area it was about 50–80 km wide. The inferred paleo-tsunami deposit includes subangular clasts that are exclusively derived from the underlying Cretaceous sandstone. Imbrication of the bouldery gravel points to landward transport of the clasts, however, a 15-cm-thick lens of cross-bedded sand records an opposing flow direction. The clayey sand matrix contains fossils, i.e. fragmented and articulated mollusc shells, as well as ostracods, that lived on the nearby sandy shoreface and offshore. The facies of the gravel indicates a short-distance transport of clasts typical for an extreme wave event. None of the depositional features e.g. various degree of clast roundness, seaward dipping imbrication, bidirectional transport indicators, clast-supported fabric, large thickness of beds, and lack of grading is either unique to tsunami deposits or excludes storm wave origin. An extreme storm wave origin, however, is discarded in this case, when paleogeography and climate are considered. The combination of matrix-supported fabric, presence of a mixed clayey-sandy matrix in the clast-supported parts, and preservation of articulated mollusc shells, as well as mixture of clasts and fossils from different zones of the shore, identify these beds as paleo-tsunami deposits. As coeval volcanism is not known, a hypothetic tsunami could have been related either to an earthquake along nearby normal faults or to large-scale sliding events on the closely located shelf slope due to rapid deposition or seismic shocks. The recognition of these event beds reinforces structural observations on the syn-depositional character of nearby faults, active after the middle Miocene climax of synrift tectonics in the Pannonian Basin. Thick, boulder-sized onshore paleo-tsunamiites are useful indicators of a paleogeographic situation in which tsunami waves were amplified to produce noticeable beds in the rock record.
Emese Laczkó-Dobos, Susanne Gier, Orsolya Sztanó, Rastislav Milovský, and Kinga Hips
Hindawi Limited
Deeply buried Pannonian (Upper Miocene) siliciclastic deposits show evidence of secondary porosity development via dissolution processes at a late stage of diagenesis. This is demonstrated by detailed petrographic (optical, cathodoluminescence, fluorescence, and scanning electron microscopy) as well as elemental and stable isotope geochemical investigations of lacustrine deposits from the Makó Trough, the deepest depression within the extensional Pannonian back-arc basin. The analyses were carried out on core samples from six wells located in various positions from centre to margins of the trough. The paragenetic sequence of three formations was reconstructed with special emphasis on sandstone beds in a depth interval between ca 2700 and 5500 m. The three formations consist, from bottom to top, of (1) open-water marls of the Endrőd Formation, which is a hydrocarbon source rock with locally derived coarse clastics and (2) a confined and (3) an unconfined turbidite system (respectively, the Szolnok and the Algyő Formation). In the sandstones, detrital grains consist of quartz, feldspar, and mica, as well as sedimentary and metamorphic rock fragments. The quartz content is high in the upper, unconfined turbidite formation (Algyő), whereas feldspars and rock fragments are more widespread in the lower formations (Szolnok and Endrőd). Eogenetic minerals are framboidal pyrite, calcite, and clay minerals. Mesogenetic minerals are ankerite, ferroan calcite, albite, quartz, illite, chlorite, and solid bituminous organic matter. Eogenetic finely crystalline calcite yielded δ13 C V − PDB values from 1.4 to 0.7‰ and δ18 O V − PDB values from –6.0 to –7.4‰, respectively. Mesogenetic ferroan calcite yielded δ13 C V − PDB values from 2.6 to –1.2‰ and δ18 O V − PDB values from –8.3 to –14.0‰, respectively. In the upper part of the turbidite systems, remnants of the migrated organic matter are preserved along pressure dissolution surfaces. All these features indicate that compaction and mineral precipitations resulted in tightly cemented sandstones prior to hydrocarbon migration. Interconnected, secondary, open porosity is associated with pyrite, kaolinite/dickite, and postdates of the late-stage calcite cement. This indicates that dissolution processes took place in the deep burial realm in an extraformational fluid-dominated diagenetic system. The findings of this study add a unique insight to the previously proposed hydrological model of the Pannonian Basin and describe the complex interactions between the basinal deposits and the basement blocks.
Krisztina Sebe, , Marijan Kovačić, Imre Magyar, Krešimir Krizmanić, Marko Špelić, Dijana Bigunac, Mária Sütő-Szentai, Ádám Kovács, Andrea Szuromi-Korecz,et al.
Croatian Geological Survey
Upper Miocene to Pliocene (Pannonian) sediments of the Pannonian Basin System accumulated in the brackish Lake Pannon and the fluvial feeder systems, between 11.6-2.6 Ma. Their stratigraphic subdivision has been problematic for a long time due to the laterally prograding architecture of the basin fill and the historically independently evolving stratigraphic schemes of the neighbouring countries. We correlated the lithostratigraphic units of the Lake Pannon deposits between Hungary and Croatia in the Drava Basin, using lithological, sedimentological and palaeontological data from boreholes and outcrops, and seismic correlation. The Croatica and Medvedski breg formations in Croatia correspond to the Endrőd Fm. in Hungary, comprising shallow to deep water, open lacustrine, calcareous to argillaceous marls. The Andraševec fm. in Croatia corresponds to the Szolnok and Algyő Fms. in Hungary, consisting of sandstones and siltstones of turbidite systems and of clay marls deposited on the shelf-break slope. The Nova Gradiška fm. in Croatia is an equivalent of the Újfalu Fm. in Hungary, built up of a variety of lithologies, including sand, silt, clay and huminitic clay, deposited in deltaic environments. The Pluska fm. in Croatia corresponds to the Zagyva Fm. in Hungary, consisting of variegated clays, silts, sands and lignites, deposited in alluvial and fluvial environments. Coarse-grained (sand, gravel) basal layers are assigned to the Kálla and Békés Fms. and the Sveti Matej member of the Croatica fm. Coarse-grained intercalations within the deep-water marls belong to the Dorozsma Member of the Endrőd Fm. in Hungary, and to the Bačun member of the Medvedski breg fm. in Croatia. Sediment transport and lateral accretion of the shelf edge in the Drava Basin took place from the N, NW, and W, to the S, SE, and E, respectively. According to the biostratigraphic and chronostratigraphic analyses, the oldest shelf-break slopes in the Mura Basin are more than 8 Ma old, whereas the youngest ones in the southeasternmost part of the Drava Basin may be Pliocene in age (younger than 5.3 Ma). Thus, the 180 km long and at least 700 m deep Drava Basin was transformed into a fluvial plain during the last 3.5 million years of the Miocene.
Emese M. Bordy, Orsolya Sztanó, Akhil Rampersadh, John Almond, and Jonah N. Choiniere
Elsevier BV
Abstract Containing one of the richest late Early to early Middle Triassic continental biotas globally, the Burgersdorp Formation of the main Karoo Basin in South Africa hosts a diverse vertebrate fossil assemblage. Comparatively, trace fossils in this unit are lesser known, and thus how the Burgersdorp biotas behaved and interacted with their palaeoenvironment remain enigmatic. Here we report on two Middle Triassic continental ichnofossil localities dominated by tetrapod scratch traces from the Anisian part (subzones B and C) of the Burgersdorp Formation in the main Karoo Basin (Eastern Cape, South Africa). Analyses of the trace fossils and associated sedimentary facies aim to identify the possible trace makers, their behaviours and the local depositional conditions in this southern part of Pangea. We establish the palaeoenvironmental context for the ichnofossils combining ichnological data with the sedimentological records of the trace fossil sites and the nearby type area of the Burgersdorp Formation. To facilitate comparisons with similar trace fossils in the future, we quantify the morphometric parameters of these Burgersdorp trace fossils in digital models. Our results show that bilobated, branching and cross-cutting furrow casts with abundant scratch traces: (a) were generated within crevasse splay deposits adjacent to laterally migrating river channels in a semi-arid setting, and (b) can be interpreted as the claw-scratched ventral walls of a therapsid burrow system with a 3D network architecture. This well-developed vertebrate burrow network complex from the Middle Triassic of South Africa is among a handful of similarly complex vertebrate trace fossils in the global pre-Jurassic ichnological record. Collectively, these trace fossils indicate that the Triassic, and in particular the Middle Triassic, was an important period in the evolutionary history of the complex vertebrate burrowing.
Katalin Báldi, Csilla Balogh, Orsolya Sztanó, Krisztina Buczkó, Ilona Bedéné Muskó, László G.-Tóth, and Zoltán Serfőző
University of California Press
Although the ecosystem transforming impact of the invasive dreissenid mussels has been widely reported in short-to-mid time scale studies, little is known about the contribution of the spent shells to sediments accumulating on the lake bottom. The question whether the shell production significantly reduces the lifespan of the lake by increasing sedimentation rate is particularly interesting in those shallow lakes where the calcium supply is sufficient to maintain the high mussel biomass production permanently, and where the alkaline water does not favor shell dissolution. Lake Balaton, a large calcareous, shallow lake in Central Europe invaded by dreissenids (Dreissena polymorpha, Dreissena rostriformis bugensis), provides an ideal testing ground for this scenario. Therefore, we made calculations based on recent population abundance datasets (2000–2018), estimated the whole habitable, hard surface coastline and the muddy bottom of the pelagic area which is also gradually becoming inhabited by D. r. bugensis, using high resolution aerial photographs and analyzing seismic sections. We created four scenarios: (1) if no dreissenids are present (applying basic sedimentation rate); (2) if D. r. bugensis had not been introduced to the lake (only D. polymorpha); (3) if D. r. bugensis occupies the hard surfaces of the coastline (the current dominant situation); (4) if D. r. bugensis colonizes the entire lake bottom (a probable future model). Different sedimentation rates obtained from the literature were used to model the filling of Lake Balaton. The shell production of the new invader, D. r. bugensis can shorten the lake’s lifespan by one to two-thirds, depending on the model, and whether the mussel density currently observed at the shoreline is extended to the whole lake bottom. Attention is called to shallow calcareous lakes with low pre-invasion sedimentation rates in which the shell contribution of invasive mollusks has the potential to shorten lifespan.
Soma Budai, Krisztina Sebe, Gábor Nagy, Imre Magyar, and Orsolya Sztanó
Springer Science and Business Media LLC
Lake Pannon, covering the Pannonian Basin (Hungary) during the Late Miocene, had a complex lake bottom with deeper sub-basins and intrabasinal basement highs, sometimes emerging above the lake level as islands and peninsulas. Above structural highs, the basin fill sequence usually commenced with deposition of transgressional, locally sourced coarse-grained deltas. These deposits are overlain by distally-sourced deltaic bodies associated with the prograding delta system that gradually filled up the entire basin. The transition between these two distinct delta systems was studied in a large outcrop on the edge of a former basement high (Mecsek Mts., southern Hungary). The transgressional phase is represented by the deposition of a mass flow dominated fan delta body, fed by local material from a granitic catchment area. An overlying fossil-rich, clayey unit records an episode for which sediment delivery into the basin was curtailed, possibly due to submergence of the granite body. The deposition of these two units took place between 8 and 6.8 Ma. The onset of sedimentation associated with the arrival of the distally sourced regressive delta system (around 6.8 Ma) is represented by deposition of shoreface sediments. This unit is characterized by distinctive bioturbation and storm related, sand filled scour-fills. Resedimented local material that forms mm thick, coarse laminas in the scour fills is indicative of denudation due to tectonic events and implies coupled storm-flood sedimentation. The deposition of the two distinct delta bodies and the interplay between tectonic events and lake-level changes occurred during a relatively short, ca. 1.5 Ma long time interval.
Chenglin Gong, Orsolya Sztanó, Ronald J. Steel, Benzhong Xian, William E. Galloway, and Gábor Bada
Geological Society of America
Chenglin Gong1,2,3,†, Orsolya Sztanó4, Ronald J. Steel3, Benzhong Xian1,2, William E. Galloway5, and Gábor Bada6 State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China College of Geosciences, China University of Petroleum (Beijing), Beijing 102249, China Department of Geological Sciences, Jackson School of Geosciences, The University of Texas, Austin, Texas 78712, USA Department of Physical and Applied Geology, Eötvös Loránd University, Pázmány Péter sétány 1/c, 1117 Budapest, Hungary Institute for Geophysics, Jackson School of Geosciences, The University of Texas at Austin, 10100 Burnet Road, Austin, Texas 78758-4445, USA TXM Oil and Gas Exploration Ltd., Infopark Street 1, 1117 Budapest, Hungary
Imre Magyar, Orsolya Sztanó, Krisztina Sebe, Lajos Katona, Vivien Csoma, Ágnes Görög, Emőke Tóth, Andrea Szuromi-Korecz, Michal Šujan, Régis Braucher,et al.
Foldtani Kozlony
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 <200 m high shelf-margin slope (Algyő Fm), and several stacked deltaic deposits from prodelta silts to sandy mouth bars, heterolithics, lignite and sandy channel-fills of the delta plain (Újfalu Fm). Magnetostratigraphic investigations from two cores and authigenic 10Be/9Be dating from two others were combined by means of seismic correlation between the boreholes, and thus they provide a solid geochronological and chronostratigraphic basis for the interpretation of the sedimentologial and paleontological records of the cores. The continuous representation of the earliest Pannonian (11.6–9.1 Ma) in the cores needs further investigation, as neither magnetostratigraphy nor authigenic 10Be/9Be dating gave reliable age data from the basal, condensed calcareous marls. The 9.1 to 6.5 Ma interval, however, is represented in the cores by various lithologies and abundant and sometimes excellently preserved fossils. In the deltaic succession, 8 sedimentary sequences were correlated between the cores; as their duration is not more than 400 kyr each, they can be regarded as 4th-order sequences. The paleontological record of the cores shows a very good agreement with the formerly established biochronostratigraphical system. The cores provide an insight into the evolution of the sedimentary environment and the biota of Lake Pannon between 9.1 and 6.5 Ma with a so far unprecedented temporal and spatial resolution.
Attila Balázs, Imre Magyar, Liviu Matenco, Orsolya Sztanó, Lilla Tőkés, and Ferenc Horváth
Elsevier BV
Abstract Lake-floor morphologies may be significantly different from seafloor topographies of other basins, typically observed in passive or active continental margins. The bathymetry of large paleo-lakes is often overwritten by subsequent tectonic evolution, burial beneath thick overburden and inherent compaction effects. We study the evolution of such an initial underfilled, balance fill and finally overfilled large paleo-lake basin by the interpretation of 2D and 3D seismic data set corroborated with calibrating wells in the example of the Neogene Pannonian Basin of Central Europe. Lake Pannon persisted for about 7–8 Myr and was progressively filled by clastic material sourced by the surrounding mountain chains and transported by large rivers, such as the paleo-Danube and paleo-Tisza. We combined sedimentological observations with a backstripping methodology facilitated by well lithology and porosity data to gradually remove the sediment overburden. This approach has resulted in a morphological reconstruction of the former depositional surfaces with special focus on the prograding shelf-margin slopes. Our calculations show that the water depth of the lake was more than 1000 m in the deepest sub-basins of the Great Hungarian Plain of the Pannonian Basin. The significant compaction associated with lateral variations of Neogene sediment thicknesses has created non-tectonic normal fault offsets and folds. These features have important effects on fluid migration and hydrocarbon trapping. We furthermore compare the geometries and effects of such non-tectonic features with the activity of larger offset sinistral strike-slip zones using 3D seismic attributes.
Nick A. Kelder, Karin Sant, Mark J. Dekkers, Imre Magyar, Gijs A. van Dijk, Ymke Z. Lathouwers, Orsolya Sztanó, and Wout Krijgsman
American Geophysical Union (AGU)
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).
Márton Szabó, Gábor Botfalvai, László Kocsis, Giorgio Carnevale, Orsolya Sztanó, Zoltán Evanics, and Márton Rabi
Palaeobiodiversity and Palaeoenvironments Springer Science and Business Media LLC
Attila Balázs, Didier Granjeon, Liviu Matenco, Orsolya Sztanó, and Sierd Cloetingh
American Geophysical Union (AGU)
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.
Christiaan G.C. van Baak, Wout Krijgsman, Imre Magyar, Orsolya Sztanó, Larisa A. Golovina, Arjen Grothe, Thomas M. Hoyle, Oleg Mandic, Irina S. Patina, Sergey V. Popov,et al.
Elsevier BV
Abstract The Black Sea and Caspian Sea are the present-day remnants of a much larger epicontinental sea on the Eurasian continental interior, the Paratethys. During the late Miocene Messinian Salinity Crisis (MSC), a unique oceanographic event where 10% of the salt in the world's ocean got deposited in the deep desiccated basins of the Mediterranean, the Paratethys Sea was connected to the Mediterranean Sea. Unlike the Mediterranean, no salt is known to have been deposited in the Paratethys region at this time, yet a similar mechanism of deep desiccation (with a water level drop of up to 2 km occurring at 5.6 Ma) has been proposed in the past to explain the late Miocene and Pliocene Paratethys basin evolution. Here, we review the basin evolution, stratigraphy and subsurface data of the four main Paratethyan sub-basins to investigate the response to the Mediterranean Messinian event. We show that hypotheses of a Paratethys-wide desiccation synchronous to the Messinian Salinity Crisis climax at 5.6 Ma do not hold. Determinations of the magnitude of the sea level drop appear to have regularly been overestimated by speculative basin-to-margin interpretations, and often been disproven by increased age model resolution. In the Euxinian (Black Sea) Basin, the most recent estimates for the magnitude of sea level drop vary between 50 and 500 m, yet the timing is debated. Marginal outcrops in the Dacian Basin highlight multiple switches from shallow basinal to littoral and fluvial environments during the MSC interval, but no major water level drop coincides with the 5.6 Ma event. The Paleo-Danube deposits filling in the Pannonian Basin do not indicate any influence by the MSC and show prograding patterns into the deepwater lake Pannon. The dramatic expansion of the Paleo-Volga delta in the Caspian Sea is shown to be younger than the MSC, while estimates of the amount of water level drop vary widely due to the poorly understood contribution of tectonic processes. These changing perspectives and decreasing estimates of water level lowering are not surprising given the vast northern drainage of the Paratethys region. Precipitation and runoff from the Eurasian continent ensures a much more positive hydrological budget under isolated conditions than the vast negative hydrological budget of the Mediterranean Sea which requires constant compensation by inflowing oceanic waters.