Ontogenetic age and body dimensions were studied on three extremely well-preserved sciaenid fish otoliths from sublittoral marls of Lake Pannon from Doba, Bakony Mts, Hungary. Macroscopic and microscopic observations offered clear evidence for the preservation of the genuine structural characteristics, for instance the bipartite incremental features. Ontogenetic ages were assigned for the three specimens as 16, 7 and 6 years by counting the annuli of the sagittae. Analytical results prove that the original aragonitic mineralogy has been preserved making them, and probably other Late Miocene teleost fossils, suitable for future microchemical analysis to reconstruct the past physicochemical environment.

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.

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As the almost 200-year palaeontological research revealed, the geographical distribution of various fossil mollusk faunas in deposits of the late Neogene Lake Pannon displays a regular pattern. The lake basin was filled by lateral accretion of sediments, resulting in condensed sedimentary successions in the distal parts of the basin and successively younger shallow-water deposits from the margins towards the basin center. Exposed intra-basin basement highs, however, broke this strict pattern when they acted as sediment sources during the lake’s lifetime. The Mecsek Mts in southern Hungary was such an island in Lake Pannon during the early late Miocene. Deposition of the 200 m thick Sarmatian–Pannonian sedimentary succession in Pécs-Danitzpuszta at the foot of the Mecsek Mts was thus controlled by local tectonic and sedimentary processes, resulting in a unique succession of facies and mollusk faunas. A typical, restricted marine Sarmatian fauna is followed by a distinct freshwater or oligohaline interval, which, according to micropalaeontological evidence, still belongs to the Sarmatian. Although poor preservation of fossils does not allow firm conclusions, it seems that freshwater Sarmatian snails were the ancestors of the brackish-water-adapted early Pannonian pulmonate snail taxa. The successive “Sarmatian-type” dwarfed cockle fauna is similar to those widely reported from the Sarmatian–Pannonian boundary in various parts of the Pannonian Basin; however, a thorough taxonomic study of its species is still lacking. The bulk of the sedimentary succession corresponds to the sublittoral to profundal “white marls,” which are widespread in the southern Pannonian Basin. In Croatia and Serbia, they are divided into the Lymnocardium praeponticum or Radix croatica Zone (11.6–11.4 Ma) below, and the Congeria banatica Zone (11.4–9.7 Ma) above; this division can be applied to the Pécs-Danitzpuszta succession as well. Sedimentation of the calcareous marl, however, ceased at Pécs-Danitzpuszta at about 10.5–10.2 Ma ago (during the younger part of the Lymnocardium schedelianum Chron), when silt was deposited with a diverse sublittoral mollusk fauna. Similar faunas are known from the Vienna Basin, southern Banat, and other marginal parts of the Pannonian Basin System, but not from Croatia and Serbia, where deposition of the deep-water white marls continued during this time. Finally, the Pécs-Danitzpuszta succession was capped with a thick, coarse-grained sand series that contains mollusk molds and casts representing a typical littoral assemblage. This littoral fauna is well-known from easternmost Austria, northern Serbia, and northwestern Romania, but never directly from above the sublittoral L. schedelianum Zone. The fauna is characteristic for the upper part of the Lymnocardium conjungens Zone and has an inferred age of ca. 10.2–10.0 Ma. The Pécs-Danitzpuszta succession thus allows to establish the chronostratigraphic relationship between mollusk faunas that have not been observed in one succession nor in close proximity to each other in other parts of the Pannonian Basin.

The Gerecse Hills, which represent the northwesternmost part of the Mesozoic-Palaeogene Transdanubian Range, are surrounded by an Upper Miocene -Pliocene (Pannonian) lacustrine to fluvial sedimentary cover to the west and to the north: namely, towards the Danube -Kisalföld Basin of Slovakia and Hungary. The oldest reports on fossil molluscs from these sediments were published almost 150 years ago. A systematic mapping of the area by geologists of the Geological and Geophysical Institute of Hungary during the last decades revealed a number of natural and artificial outcrops of fossiliferous Lake Pannon sediments. The present study is based on the molluscs collected from these outcrops, and the sedimentological description and interpretation of the embedding sequences.The Upper Miocene deposits near the Gerecse Hills comprise one transgressive-regressive cycle. In the brickyard claypits of Tata, located in the western foreland of the Gerecse Hills, the transgressive limb is represented by the Szák Formation. This formation starts with a thin transgressive lag and consists of homogeneous, bioturbated, bluish-grey clay and argillaceous marl, deposited from suspension in quiet offshore conditions. Characteristic mollusc species include large dreissenids (Congeria czjzeki, C. partschi, C. ungulacaprae), a wide variety of cockles (Lymnocardium tegulatum, L. triangulatocostatum, L. majeri, L. apertum, L. aff. brunnense, L. aff. rogenhoferi, "Pontalmyra" otiophora, Paradacna sp.), and deep-water-adapted pulmonate snails (Valenciennius reussi, Radix kobelti, Gyraulus sp.). This fauna lived in a nutrient-rich and well-oxygenated deep sublittoral environment, at a water depth of several tens of metres.Probably the same transgressive event is reflected in the Vályus-kút outcrop (Tardos), in the central part of the hills at 375 m above sea level, where a small patch of Lake Pannon sediments escaped subsequent erosion. In this sequence, lignite-bearing black clay and variegated clays with freshwater and terrestrial molluscs (Theodoxus radmanesti, Melanopsis sturi sturi, M. sturi tortispina, Planorbidae sp., Unionidae sp., Valvata oecsensis, V. obtusaeformis, Oxychilus procellarius) are overlain by clay and silt with Congeria czjzeki, Lymnocardium majeri, and other brackish species. This superposition indicates flooding of paludal areas, deepening, and the development of an intense connection with the sublittoral offshore environment of Lake Pannon.A third -and highly atypical -type of lower contact of Pannonian sediments was discovered in one of the northern valleys of the Gerecse Hills (Iván-halála Valley, Dunaszentmiklós). A poorly-sorted conglomerate consisting of cobbleand boulder-sized clasts with a sandy-clayey matrix overlies directly a Cretaceous sandstone. Imbrication of the clasts indicates a N to S transport direction i.e. from the open lake towards the dry land. The matrix contains abundant mollusc fauna, including articulated valves of Congeria aff. simulans turgida, Dreissenomya (Sinucongeria) arcuata, Pa...