Pannonian Sediments Research Articles

Granulometric properties of particles in Upper Miocene sandstones from thin sections, Szolnok Formation, Hungary

Particle size and shape are among the most important properties of sedimentary deposits. Objective and robust determination of granulometric features of sediments is a challenging problem, and has been standingin the focal point of sedimentary studies for many decades. In this study, we provide an overview of a new analytical approach to characterize particles from thin sections of sandstones by using 2D automated optical static image analysis. The analysed samples are originated from the turbiditic Lower Pannonian (Upper Miocene) sediments of Szolnok Formation. Sandstone samples were analysed from 1,500 to 2,250 m depth range. According to the previous studies: the detrital components are quartz, muscovite, dolomite, K-feldspar and plagioclase. Diagenetic minerals are mostly carbonates (calcite, Fe-dolomite, ankerite, siderite), clay minerals (illite, kaolinite), ankerite, siderite and kaolinite. As the discussed Szolnok Formation is considered as a potential CO2 storage system (to reduce atmospheric CO2 concentration), special attention has to be paid on grain size and shape alteration evaluation, since pore water-rock interactions affected by CO2 injection may cause changes in particle properties. The primarily aim of the present study was to develop a method for effective characterization of the particle size and shape of sandstones from thin sections. We have applied a Malvern Morphologi G3SE-ID automated optical static image analyser device, what is completed with a Raman spectrometer. Via the combined analysis of granulometry and chemical characterization, it was obvious that there were specific relationships among various grain shape parameters (e.g., circularity values correlate to width and length ratios, as well as to convexity) and the results indicated that based simply on particle shapes, muscovites can be effectively separated from other minerals. Quartz and feldspar grains showed the highest variability in shapes as these are detrital ones, and sometimes arrived as lithic fragments from which other parts were dissolved The size and shape of carbonate minerals depends highly on the original pore size and shape because these minerals are mainly diagenetic. The shape of detrital dolomites depends on diagenetic ankerite, as it replaces the rim of dolomites.

ʻ...Finding a smoother pebble or prettier shell than ordinary’ – Non-utilitarian artefacts in the upper palaeolithic – A case study from Mogyorósbánya (Transdanubia, Hungary)

During the excavations of the Upper Palaeolithic site at Mogyorósbánya several non-utilitarian artefacts were found. Beside the earlier published piece of fossil resin (amber) and lumps of red ochre, more than one hundred Palaeogene and Neogene fossil molluscs, large foraminifers, corals and trace fossils from at least three different geological formations, as well as numerous fragments of phyllite were documented. Pebbles of this soft shale were most probably collected from the alluvium of the Danube river. The majority of the pieces show clear traces of scraping and along the periphery of the largest artefact rhythmic incisions are visible. Even if this piece is not a ready-made object, it can be compared to the limestone and sandstone pebbles found on the Epigravettian site of Pilismarót-Pálrét. Another interesting artefact of unknown function is a carefully shaped but strongly fragmented piece with sharp edge. Fossils of the Eocene Epoch were easily accessible in the region of Mogyorósbánya, while the nearest fossiliferous outcrops of the Oligocene and Pannonian sediments are found 15–17 km in south-eastern direction from the site. Few gastropod shells show unambiguous traces of human modification. Typically, among the 16 Melanopsis fossils found in a single square meter only three pieces were manufactured. On the other hand, the majority of the Dentalium and worm tube fragments were cut and their surfaces show intense rounding and shine. The not modified Nummulites, corals and large internal casts of gastropods were most probably collected by Prehistoric humans because of their unusual form. This interesting group of the Mogyorósbánya artefacts and are compared to the fossils published from the Pilisszántó I rockshelter and to the not modified fossils from Moravia and Romania.

Marsh-type agglutinated foraminifera from Upper Miocene sediments of the Danube Basin

Upper Miocene (lower Tortonian) foraminifers are a little-known group of organisms in the Pannonian Basin System of the Central Paratethyan realm. The scarcity of the mostly endemic species in the sedimentary record is caused by changes in ecological conditions at the end of the Miocene epoch when the paleogeographical evolution of the area resulted in the striking changes in seawater chemistry. Nevertheless, they may exceptionally form a significant component of microfossil assemblages. The most abundant species within all studied samples (Trochammina kibleri Venglinsky 1961, Miliammina velatina Venglinsky 1961 and Miliammina subvelatina Venglinsky 1975) are here investigated in detail and compared with previously published data from localities across the entire Central Paratethys area. The co-occurrence of other taxa, as well as sedimentological and isotopic data allow us to better constrain their environmental requirements and the sedimentary environment in marginal facies of the Late Miocene Pannonian Basin System. These results confirm the ecologically constrained conditions during the deposition of the upper Sarmatian to lower Pannonian sediments.

A Gerecse pannóniai puhatestűi és lelőhelyeik: rétegtan, őskörnyezet és fejlődéstörténet

A Gerecse földtani térképezése során a Magyar Földtani és Geofizikai Intézet geológusai új, vagy régen feledésbe merült és részletesen soha nem dokumentált pannóniai feltárásokat azonosítottak a hegység északi előterében, az onnan dél felé felnyúló völgyekben, és a hegység belsejében is. Az ezekből begyűjtött puhatestű fauna (kiegészítve a már korábban ismert tatai puhatestű faunával és régebbi gyűjteményi anyagokkal) és a feltárásokban megfigyelhető szedimentológiai jellemzők alapján a pannóniai rétegsor itt is, mint az egész Dunántúli-középhegység északnyugati peremén, egyetlen transzgresszív-regresszív ciklusból áll. A ciklus transzgresszív szárnyát a tatai téglagyári feltárásokban a vékony transzgresszív bázisrétegre települő Száki Formáció kékesszürke agyagja és az abban megőrződött mély szublitorális fauna, míg a Gerecse központi részén, a tardosi Vályus-kút környékén, 375 méter tengerszint feletti magasságban a lignites agyaggal kezdődő rétegsor fedőjében települő, szintén mély szublitorális puhatestűeket tartalmazó agyag képviseli. A dunaszentmiklósi Iván halála-völgyben valószínűleg egy szökőár hozta létre a kréta fekü anyagából képződött konglomerátumot, homokos mátrixában tömegesen megjelenő zárt (két teknős) pannóniai kagylóhéjakkal. Az üledékciklus regresszív szárnyát az Újfalui Formáció képződményei adják; ezek legjobb feltárásai a Gerecse északi előterében, a Neszmély környéki völgyekben (Nyáraska-völgy, Disznós-kúti-völgy, Csekendi-völgy) és Süttő környékén találhatók. A formációt felépítő felfelé sekélyedő, néhány méter vastag ciklusok faunája a kagylók uralta sekély szublitorális együttesekből, a csigák magas diverzitásával jellemzett litorális faunákból és végül mocsári puhatestű együttesekből áll. Gyűjteményi anyagokban előfordulnak folyóvízi fajok is. A transzgresszív szárny a Congeria czjzeki zóna felső részébe tartozik, míg a regresszív szárny a Lymnocardium ponticum zóna része; a teljes ciklus képződésének kora 9,4–8,7 millió év lehetett. A fáciesek elterjedése alapján a transzgresszió már tagolt térszínen játszódott le, majd az üledékképződéssel egyidejűleg is folyt a terület vetődéses deformációja, de a tatai és vályus-kúti rétegsorok közötti nagy magasságbeli különbség csak további vetőmozgásokkal, a Gerecse utólagos kiemelkedése nyomán jöhetett létre.

Latest Pannonian and Quaternary evolution at the transition between Eastern Alps and Pannonian Basin: new insights from geophysical, sedimentological and geochronological data

The transition zone between Eastern Alps and Pannonian Basin is a key area for the investigation of the interplay between regional uplift, local tectonic subsidence and depositional environment. Our study area, the western margin of the Little Hungarian Plain, is characterized by gentle hills, plateaus and depressions, of which several are filled by lakes—including one of Austria’s largest and shallowest lakes, Lake Neusiedl. Geological investigation is hampered by the scarcity of outcrops, and thus direct observation of sedimentological or structural features is difficult. Despite a long research history in the area, a consistent landscape evolution model considering all relevant constraints is lacking so far. In this study, we apply multidisciplinary methods to decipher the complex tectonic and fluvial depositional evolution of the region. Local data from shallow-lake drilling and seismic investigation are combined with regional data from industrial seismics and core data to gain new insights into the latest Pannonian (Late Miocene) and Quaternary evolution. Shallow-lake seismic data show the erosionally truncated Pannonian sediments dipping and thickening toward southeast, toward the modern depocenter of the Little Hungarian Plain. Overlying Quaternary fluvial sediments show a very similar thickening trend except for the area on the plateau north of the lake indicating ongoing subsidence in major parts of the basin. Drill cores from locations along the lake seismic lines were analyzed concerning their age, mineralogy and heavy minerals and compared with outcrop samples from the surrounding plains and the plateau to derive indications on sediment provenance. A key observation is the apparent lack of a significant gravel layer on top of the tilted Pannonian sediments beneath Lake Neusiedl. Small-scale faults can be observed in the lake seismic sections along with key sedimentary features. Significant differences of the current elevation of the top Pannonian between the surrounding plains and the plateau indicate post-Pannonian normal faulting, which is a key process in shaping the present-day morphology of the region. Luminescence ages of samples from the Quaternary fluvial gravels on top of the Pannonian sediments are a significantly higher (>300 ka) compared to the gravels in the plain (102 ± 11 and 76 ± 8 ka), suggesting ongoing tectonic subsidence.

Paleomagnetic and chronostratigraphic constraints on the Middle to Late Miocene evolution of the Transylvanian Basin (Romania): Implications for Central Paratethys stratigraphy and emplacement of the Tisza–Dacia plate

From the Oligocene onwards, the complex tectonic evolution of the Africa–Eurasia collision zone led to paleogeographic and biogeographic differentiation of the Mediterranean and Paratethys, two almost land-locked seas, in the area formerly occupied by the western Tethys Ocean. Episodic isolation of the basins triggered strong faunal endemism leading to the introduction of regional stratigraphic stages for the Paratethys. Chronostratigraphic control on the Paratethys stages remains rudimentary compared to the cyclostratigraphically constrained Mediterranean stages. This lack of chronostratigraphic control restricts the insight in the timing of geodynamic, climatic, and paleobiogeographic events and thereby hinders the identification of their causes and effects. In this paper, we here derive better age constraints on the Badenian, Sarmatian and Pannonian Central Paratethys regional stages through integrated 40Ar/39Ar, magnetostratigraphic, and biostratigraphic research in the Transylvanian Basin. The obtained results help to clarify the regions Middle Miocene geodynamic and paleobiogeographic evolution. Six new 40Ar/39Ar ages were determined for tuffs intercalating with the generally deep marine basin infill. Together with data from previous studies, there is now a total of 9 radio-isotopically dated horizons in the basin. These were traced along seismic lines into a synthetic seismic stratigraphic column in the basin center and serve as first order tie-points to the astronomically tuned Neogene timescale (ATNTS). Paleomagnetically investigated sections were treated similarly and their polarity in general corroborates the 40Ar/39Ar results. The integrated radio-isotopic and magnetostratigraphic results provide an improved high-resolution time-frame for the sedimentary infill of the Transylvanian Basin. Early Badenian deep water sedimentation is characterized by accumulation of the Dej Tuff Complex in response to a period of intensive volcanism, the onset of which is constrained between the first occurrence (FO) of Orbulina suturalis at 14.56Ma and 14.38±0.06Ma. During the subsequent Badenian Salinity Crisis (BSC) up to 300m of salt accumulate in the basin center. The faunal turnover that marks the Badenian–Sarmatian Boundary is dated at 12.80±0.05Ma. A second phase of intense volcanism occurs at 12.4Ma and leads to deposition of the middle Sarmatian tuff complex (Ghiriş, Hădăreni, Turda and Câmpia Turzii tuffs). Rates of sediment accumulation strongly diminish in the basin center at the onset of the Pannonian stage coincident with an approximately 20° CW tectonic rotation of the Tisza–Dacia plate. Concurrent enhanced uplift in the Eastern a'nd Southern Carpathians leads to the isolation of the Central Paratethys and triggers the transition from marine to freshwater conditions. An additional Pannonian to post-Pannonian 6° of CW rotation is related to the creation of antiform geometries in the Eastern Carpathians which are notably larger in the north than in the south. An 8.4Ma age is determined for the uppermost Pannonian sediments preserved in the central part of the Transylvanian Basin. Two sections belonging to middle Pannonian Zone D, and the lower part of Zone E (Subzone E1) are found to cover the 10.6–9.9Ma time-interval.

Statistical analysis of Neogene sediment thickness deposited during the first transtensional and first transpressional evolutionary stages in the Bjelovar Sub-basin, Northern Croatia

Abstract The Bjelovar Sub-basin is situated in Northern Croatia and constitutes the southwestern branch of the Drava Basin. The Neogene-Quaternary sedimentary section can be subdivided into three megacycles, which are separated by regional unconformities. The data analyzed in this study are related to the first megacycle, which is characterized by a tectonic-erosional unconformity above the Neogene basement (electric log, abbr. e-log marker Pt or Tg); its top is the regional e-log marker Rs7. It is generally assumed that the Rs7 marker separates Sarmatian and Pannonian sediments and indicates the period just after the first transtensional and first transpressional events. The youngest elog marker, Rs5, represents the Lower/Upper Pannonian boundary (in Croatian stratigraphic nomenclature) and more generally the early period of the second transtensional event. The lithology of the Lower and Middle Badenian is characterized by coarse and medium-grained sediments, while the Upper Badenian to Lower Pannonian s...

Late Miocene and Pliocene history of the Danube Basin: inferred from development of depositional systems and timing of sedimentary facies changes

Late Miocene and Pliocene history of the Danube Basin: inferred from development of depositional systems and timing of sedimentary facies changesThe development of the northern Danube Basin (nDB) was closely related to the Late Miocene geodynamic evolution of the Pannonian Basin System. It started with a wide rifting which led to subsidence of several basin depocenters which were gradually filled during the Late Miocene and Early Pliocene. In the Late Pliocene the subsidence continued only in the basin's central part, while the northern marginal zone suffered inversion and the uplifted sedimentary fill began to be eroded. Individual stages of the basin development are well recorded in its sedimentary succession, where at least three great tectono-sedimentary cycles were documented. Firstly, a lacustrine cycle containing Lower, Middle and lowermost Upper Pannonian sediments (A-F Zones;sensuPapp 1951) deposited in the time span 11.6-8.9 Ma and is represented in the nDB in Slovakia by the Ivanka and Beladice Formations. In the Danube Basin of the southern part in Hungary, where the formations are defined by the appearance of sedimentary facies in time and space, the equivalents are: (1) the deep-water setting marls, clays and sandy turbidites of the Endrod and Szolnok Formations leading to the overlying strata deposits of the basin paleoslope or delta-slope represented by the Algyő Formation, and (2) the final shallow-water setting deposits of marshes, lagoons and a coastal and delta plain composed of clays, sands and coal seams, represented by the Újfalu Formation. The second tectono-sedimentary cycle was deposited in an alluvial environment and it comprises the Upper Pannonian (G and H Zones;sensuPapp 1951) and Lower Pliocene sediments dated 8.9-4.1? Ma. The cycle is represented in the nDB, by the Volkovce Formation and in the southern part by the Zagyva Formation in Hungary. The sedimentary environment is characterized by a wide range of facies from fluvial, deltaic and ephemeral lake to marshes. The third tectono-sedimentary cycle comprises the Upper Pliocene sediments. In Slovakia these are represented by the Kolárovo Formation dated 4.1-2.6 Ma. The formation contains material of weathering crust preserved in fissures of Mesozoic carbonates, diluvial deposits and sediments of the alluvial environment.

Evolution of lignite seams within the South Moravian Lignite Coalfield based on certain qualitative data

Abstract This paper focuses on evolution of lignite seams (the Pannonian) in the South Moravian Lignite Coalfield (SMLC). It is based on data analysis (seam geometry, ash yield, sulfur content, and lithology) from more than 3300 boreholes and many channel samples. The results show that the Vienna Basin in the Pannonian period gradually developed into a freshwater bay. In the Early Pannonian the sedimentary environment was tectonically calm. The salinity of the sedimentary environment was changing as a consequence of recurring transgressions. The studied area was under the influence of rivers flowing into the region from the west, north, and northeast. In the upper part of zone B (Papp's classification of the Pannonian sediments), especially in the northern areas of the SMLC, suitable conditions for coal-bearing sedimentation (the Kyjov seam) occurred. Zones C–F were characterized by simple or incomplete cyclic sedimentation processes. The Vienna Basin opened and the subsidence between the Steinberg fault zone and Lužice–Lanžhot fault zone (interconnected with the Polesovice fault zone) took place in the SMLC. At the beginning of zone F the swamp areas suitable for Dubňany seam formation developed in the SMLC. The coal-forming conditions were repeatedly restored. The sedimentary cycles with the coal-bearing deposits occurred also in zone G, however only in the central and southern parts of the SMLC. The increasing thickness of the deposits in zone G and the increasing number of cycles with lignitic layers in the southern part of the SMLC indicate a shift of the suitable conditions for swamps towards the south and into the overlying rocks. A distinct tectonic deformation of the lignite seam in the SMLC started only in the Pliocene, when due to the change of the stress field in the Vienna Basin the rejuvenation of the tectonic zones of the pull-apart system took place towards the NE–SW and NW–SE to NNW–SSE.

Upper Miocene Pannonian sediments from Belgrade (Serbia): new evidence and paleoenvironmental considerations

Upper Miocene Pannonian sediments from Belgrade (Serbia): new evidence and paleoenvironmental considerationsThe Late Miocene sublittoral marls of the Pannonian Stage (the long-lived Lake Pannon) were studied. From neotectonic point of view, the investigated area represents a natural border between two different morphostructural domains: the Pannonian Basin to the north and the Peri-Pannonian Realm to the south. More than 20 mollusc and 34 ostracod species were identified which indicate the upper part of the Lower Pannonian and the lower part of the Middle Pannonian ("Serbian") predominantly. The identified dinoflagellate cyst assemblage (21 taxa) hinders assignment of the studied samples to a Pannonian substage but supports the high endemism of the Pannonian flora. The lithostratigraphical, paleontological, and paleoecological analyses indicate a mesohaline (8-16 ‰), sublittoral (<90 m deep) environment of the early Lake Pannon. The estimated stratigraphic range for the investigated deposits is 9.8-11.4 Ma.

Geology of the Čoka structure in northern Banat (Central Paratethys, Serbia)

Geology of the Čoka structure in northern Banat (Central Paratethys, Serbia)The Čoka structure is a fault-bounded anticline in northern Banat, in the southern part of the Neogene Pannonian Basin. The structure and its vicinity were explored by 24 wells. In addition to well logs, paleontological, sedimentological and petrological analyses of cores and 27 seismic sections with different parameters of acquisition and processing were used for geological investigation of the area. The E-SE dipping pre-Neogene basement consists of Lower Triassic clastics and, in the NW part of the study area, Paleozoic greenschists. Thin Middle Miocene (Badenian) sediments unconformably overlie the basement and pinch out towards the elevated NW part of the study area. They are also missing in some wells on the apex of the Čoka structure, probably due to erosion. Badenian sediments were deposited in a shallow marine environment. The late Middle Miocene (Sarmatian) strata are missing and the Badenian is directly overlain by Upper Miocene (Pannonian) sediments. The latter also pinch out towards the NW but in contrast to Badenian sediments, they are present in all boreholes on the Čoka structure. Pannonian deposition took place in a caspibrackish environment of Lake Pannon, with predominance of marls and fine-grained clastics. Pannonian sediments are conformably overlain by latest Miocene (Pontian) and Pleistocene lacustrine, alluvial and terrestrial sediments.

The Upper Miocene Lake Pannon marl from the Filijala Open Pit (Beocin, northern Serbia): New geological and paleomagnetic data

This work presents major lithological, structural, paleontological and paleomagnetic characteristics of the Upper Miocene Pannonian marl in the Filijala Open Pit of the La Farge Cement Plant near Beocin, northern Serbia. Pannonian marl lies between the underlying heterogeneous Sarmatian deposits and the overlying set of Pontian sand beds and Quaternary sediments. The open pit is located on the NE range of Fruska Gora, a horst structure with a core of Paleozoic, Mesozoic and Paleogene rocks in a complex structural pattern. Pannonian sediments, which are part of a younger structural stage, deposited on the horst limbs. The Pannonian marl strata dip at angles from 12? to 26? (to the NNW), forming a monocline. The strata deformations are a consequence of radial tectonics and are a potential source of landslides. The many mollusks (7 gastropod and 9 bivalve species) and ostracodes (27 species) and their biostratigraphical position indicate marl deposition throughout the Pannonian age. A paleomagnetic investigation established that the marl has inconsistent remanent magnetization (with bad statistical parameters), which originates from neoformed magnetite.

Origin, chemical and isotopic evolution of formation water in geopressured zones in the Pannonian Basin, Hungary

In the central part of the Pannonian Basin we investigate formation waters from two deep sub-basins with sedimentary sequences up to 7000 m thick, and from fields above basement highs where the total thickness of the sediments is only 2000 m. In each study region the depth interval involves the Lower (lower part of the Upper Miocene) and Upper (upper part of the Upper Miocene and Pliocene) Pannonian sediments separated with a widespread aquitard, named the Algyő Formation, at the top of the Lower Pannonian. However, in the fields above basement highs, it occasionally contains sand lenses, sedimentological discontinuities, faults and fractures resulting in a more conductive character. We investigate the sources and evolution of the formation waters in two geological settings: in sub-basins and in fields above an elevated basement. We distinguish NaHCO 3-type water in the sub-basins and NaCl-dominated water in the fields above the elevated basement. The isotopic composition of most NaHCO 3-type samples indicates a pure paleometeoric origin, while a few samples are a mixture of paleometeoric and non-meteoric waters. The NaCl-type samples all have a non-meteoric contribution. We have developed a model for the origin and evolution of the formation water that operates for both water types and both geological conditions. The Cl − dominated water is a mixture of ascending pre-Pannonian evaporated water and freshening Lake Pannon water trapped during the Late Miocene and Pliocene sedimentation in the area above the elevated basement, where in some places the Algyő Formation is conductive. The source and evolution of the NaHCO 3 non-meteoric water in the sub-basins are similar to those of the NaCl water, with the main difference being the aquitard character of the Algyő Formation in the sub-basins. The aquitard consists of siltstone and clay-marl, which has resulted in overpressure in the layers under the Algyő Formation. The ascending pre-Pannonian water, which mixes with in-situ pore water squeezed through the compacted clay by overpressure, is exposed to microfiltration. The Cl − remains behind, and the squeezed water is depleted of the heavier isotopes. These processes are shown by recent chemical and isotopic data ( δ 18O and δD), as well as by archival chemical and hydrological data.

Fault slip analysis in the Koralm Massif (Eastern Alps) and consequences for the final uplift of “cold spots” in Miocene times

The Paleogene and Neogene evolution of Austroalpine basement units east of the Tauern Window is characterised by the formation of two major sets of faults: (1) ESE–WNW- to E–W-trending faults, associated with ENE- and NNW-trending conjugate structures and (2) N–S to NNE-SSW striking structures, mainly acting as high-angle normal faults, often associated with E-dipping low-angle normal faults along the western margin of the Styrian Basin.Together with the stratigraphic evolution of the Styrian and Lavanttal Basins and the related subsidence histories a tectonic evolution may be reconstructed for this part of the Eastern Alps. In the southern part of the Koralm Massif, WNW-trending fractures were activated as dextral strike-slip faults, associated with the evolution of WNW-trending troughs filled up with coarse block debris. W- to WNW-trending fractures were reactivated as normal faults, indicating N–S extension. It is assumed that these phases resulted in subsidence and block debris sedimentation in Karpatian and Badenian times (ca. 17–13 Ma).In the Western Styrian Basin no Sarmatian (13–11.5 Ma) sediments are observed; Pannonian (11.5 to 7.1 Ma) sediments are restricted to the Eastern Styrian Basin. This indicates, that the Koralm basement and the Western Styrian Basin were affected by post-Sarmatian uplift, coinciding with a re-activation of N-trending normal faults along the eastern margin of the Koralm Massif. Therefore, we suggest that the final uplift of the Koralm Complex, partly together with the Western Styrian Basin, occurred during the early Pannonian (at approximately 10 Ma). The elevation of clastic deposits indicates that the Koralm Complex was elevated by approximately 800 m during this phase, associated with an additional phase of E–W-directed extension accommodated by N–S striking normal faults.

A limnic ostracod fauna from the surroundings of the Central Paratethys (Late Middle Miocene/Early Late Miocene; Styrian Basin; Austria)

Aquatic biota of the marine Middle Miocene Paratethys and the Late Miocene Pannonian Lake, a long-lived lake in Central and Eastern Europe, are well known. However, knowledge of the marginal freshwater environments is still rather poor. Recently, a thin-shelled ostracod fauna was discovered in Late Sarmatian to Early Pannonian sediments of a clay pit at the northern margin of the Styrian Basin (St. Stefan, N Graz). 11 taxa are described taxonomically of which some are left in open nomenclature due to insufficient preservation: Vestalenula cylindrica (Straub, 1952), Paracandona cf. euplectella (Robertson, 1889), Candona ( Camptocypria) gratkornensis n. sp., Candona (?) sp., cf. Candonopsis arida Sieber (1905), ? Cypria sp., Cyclocypris nitida Sieber (1905), cf. Bradleystrandesia reticulata (Zaddach, 1844), Stenocypris sp., ? Cypridopsis sp., “Striate ostracod sp.”. The ostracod associations point to a shallow, sometimes richly vegetated, limnic environment. Indications of a “warm”, maybe subtropical climate are suggested by the occurrences of Vestalenula, cf. Candonopsis, ? Cypridopsis and Stenocypris. The ostracod fauna indicates a freshwater environment, detached from the marine Sarmatian Sea and respectively from the brackish Pannonian Lake and provides hereby an insight into the palaeohabitats of the surrounding wetlands.

A field test of imaging properties of rotational invariants of the magnetotelluric impedance tensor

ABSTRACTA part of the Békés Basin (an extensional sub‐basin of the Pannonian Basin, where the basement under thick Pannonian sediments is well known from deep boreholes and from seismic measurements, and where many magnetotelluric (MT) soundings have been carried out for frequencies ranging from 1 to 10−3 Hz) was selected as a test area to assess the imaging performances of various apparent‐resistivity definitions computed with rotational invariants of either the real part of the complex impedance tensor, or its imaginary part, or both. A comparison (based on earlier 3D numerical studies) has been made between the magnetotelluric images obtained in this way and the depths to the high‐resistivity basement, as known from boreholes and seismic investigations. The correlation coefficient between the series of basement depth values at 39 MT sites and the apparent‐resistivity values was found to be stronger and high correlation appeared at a shorter period when it was computed with apparent resistivities based on the real tensor rather than with apparent resistivities based on the imaginary tensor. In the light of our studies, ρReZ and the impedance phase seem to be more informative than any other combination of magnetotelluric interpretation parameters.

Connected fluid evolution in fractured crystalline basement and overlying sediments, Pannonian Basin, SE Hungary

Uplifted crystalline basement highs have played an important role in the hydrologic history of the Pannonian Basin providing conduits for fluid migration during basin evolution. Petrographic, stable isotope, electron microprobe and fluid-inclusion studies support a five–step basin evolution; (1) formation of crystalline core-complexes, (2) percolation of meteoric water through shear zones, (3) basinwide thermal subsidence, (4) hydrologic inversion, and (5) tectonic inversion. Brittle fractures in the basement are the results of uplift during core complex formation and contain pyrite, kaolin, illite, chlorite, calcite, and quartz. Hydrocarbon stains between calcite and quartz and yellow fluorescent, primary, hydrocarbon inclusions in quartz are indicative of migrations of hydrocarbon-bearing fluids during uplift from mid-crustal depth. Further uplift was associated with meteoric water infiltration along shear-zones as recorded by light δ 13C and δ 18O values, low trace element concentrations, all-liquid primary fluid inclusions and encased pollens and cuticules of terrestrial plants in a second fracture-calcite crystallised after quartz. A simultaneous meteoric influence in the overlying Pannonian (12.7–3 Ma) sediments is indicated by extensive plagioclase dissolution, calcite cement geochemistry and low-salinity, all-liquid fluid inclusions. The thermal subsidence of the basin led to isolation of the hydrologic system from the surface. Diminishing meteoric influence is recorded by increasing fluid inclusion salinities of secondary inclusions in calcite and quartz in the basement fractures and of primary inclusions hosted in late calcite and quartz in the sediments. A sudden decrease of the fluid inclusion salinities from 4.5 to 1 wt.% NaCl eq. at ∼130°C both in burial cements and fracture-filling minerals represents a newly established hydrological system, which redistributed the interstitial fluids, including hydrocarbons. This hydraulic inversion is indicated by abundant fluorescent, secondary fluid inclusions in fracture-filling minerals. Finally, the Pliocene to recent tectonic inversion reopened fractures in the crystalline basement, and induced a rapid crystallisation of laumontite. These results support a long-standing (late Miocene to recent) hydraulic connection between fractured crystalline basement and overlying sediments in the central part of the Pannonian Basin.

Some species of the Genus Hemicytheria Pokorny (Ostracoda, Crustacea) from the Upper Miocene of Serbia

The ostracod genus Hemicytheria is very important for biostratigraphy of the caspibrackish deposits of the Pannonian basin. More than twenty species are known from regions of central Serbia and adjacent provinces. Most of them being found in the Pannonian and Pontian sediments (Sokac, 1972; Krstic, 1985; Rundic, 1992, 1993, 1997). Herein, three new species are reported for the first time: Hemicytheria setosa n. sp., Hemicytheria carinata n. sp., Hemicytheria portaferrica n. sp.

New Congerian Species and Their Similarity with Congeria banatica from the Pannonian Sediments in Northern Croatia

Congeria baschi n.sp. and Congeria susedana n.sp. are two new species from the Pannonian sediments of the Medvednica Mts. (NW Croatia). C. baschi n. s p . was found in the Lower Pannonian limestones, and C. susedana n.s p . was collected from the Upper Pannonian marls. Relationships with the affiliated taxa enable reconstruction of a phyletic lineage beginning with Congeria soceni JEKELIUS, through C. baschi n.sp. to Congeria banatica HORNES. C. banatica is the ancestor of two branches, leading to C. susedana n. sp. and C. vugro veci SREMAC, respectively. Dreissenomya digitifera (ANDRUSOV) is the probable descendant of C. vugroveci. The accompanying assemblages of fossil molluscs and ostracods from the same horizons facilitate the precise stratigraphic and palaeoenvironmental positioning of the new taxa.

Sculpturing of moldavites and the problem of micromoldavites

Nininger and Huss stated in 1967 that the sculpturing of the surfaces of two very rare indoehinites from South Vietnam occurred in the atmosphere and was not due to etching by soil agencies. However, very important and convincing features observed in moldavites and reported in this paper support the opinion that moldavite sculpturing is due to chemical corrosion in soils and gravels. It is concluded that when moldavites fell on the earth's surface they were already cool solid bodies. Many of the falling moldavites, however, were fragmented on landing. All of them, emplaced in the soil, were strongly corroded. Pure (hyaline) and translucent glassy drops, a few tenths of a millimeter in diameter, have been separated by washing the material encountered by an 80-m-deep bore through Pannonian sediments in southern Moravia. These glassy drops may have been produced as slag spherules from steam engines; they may have been in the volcanic dust from Slovakian rhyolites; or they may be micromoldavites. To solve this problem, a more detailed investigation would be necessary.