A unique Valanginian paleoenvironment at an iron ore deposit near Zengővárkony (Mecsek Mts, South Hungary), and a possible genetic model

Abstract The spatially restricted Early Valanginian iron ore (limonite) and manganese deposit at Zengõvárkony (Mecsek Mts, southern Hungary) contains a rich, strongly limonitized, remarkably large-sized (specimens are 30–70% larger than those at their type localities) brachiopod-dominated (mainly Lacunosella and Nucleata) megafauna and a diverse crustacean microfauna, which indicates a shallow, nutrient-rich environment possibly linked to an uplifted block, and/or a hydrothermal vent

Bajocian synsedimentary tectonics and its significance in Jurassic evolution of the Pieniny Klippen Basin

The Jurassic crinoidal limestones in the Pieniny Klippen Belt in Poland consist of three formations (Smolegowa, Flaki and Krupianka Limestone formations), and constitute an important segment of the Middle Jurassic sequence in the Czorsztyn, Niedzica and Czertezik successions. The onset of the crinoidal sedimentation, as proved by ammonite faunas, took place during the Early Bajocian and it was preceded by a marked stratigraphical hiatus. This hiatus corresponds to the origin and uplift of the Czorsztyn Ridge. The evidences of condensation event at the beginning of crinoidal limestones sedimentation are marked by numerous sedimentological features in the lowermost part (10-20 cm in thickness) of these limestones (e.g. phosphatic concretions concentration, pyrite concretions, large clasts of green micritic limestones). Occurrence of such important correlation horizon indicates primary thickness of investigated crinoidal limestones (from ca 10 m up to 100 m), and suggests origin of synsedimentary tectonic blocks and troughs, which influenced on their original, not recently tectonically reduced, differentiation of their thickness. This Bajocian tectonic activity within Pieniny Klippen Basin corresponds very well with others Middle Jurassic Western Tethyan geodynamic reorganizations

Stratigraphic position of the Bajocian crinoidal limestones and their palaeogeographic significance in evolution of the Pieniny Klippen Basin

The chronostratigraphical position of the crinoidal limestones in the Pieniny Klippen Belt (Carpathians, Poland) is well documented by ammonite faunas. It corresponds to the stratigraphical interval from the uppermost Propinquans and lowermost Humphriesianum zones of the Lower Bajocian to the Garantiana Zone of the Upper Bajocian. The hiatus recognized at the base of the crinoidal limestone complexes covers the time interval of the Laeviuscula Chron and a bulk of the Propinquans Chron of the Early Bajocian. The sedimentological features found in the basal beds of the crinoidal limestones include: presence of numerous phosphatic concretions, occurrence of pyrite framboids, as well as numerous rests of fauna (mostly ammonites and belemnites), all of them showing a slow sedimentation rate. The rapid change of sedimentation from dark shales of oxygen-depleted environment (Skrzypny Shale Fm. – Aalenian to earliest Bajocian) to overlying light crinoidal grainstones (Smolegowa Limeston Fm., Flaki Limestone Fm.) corresponded to an important geodynamic event that took place during Early Bajocian – the origin of the mid-oceanic Czorsztyn Ridge

Early Cretaceous intra-plate volcanism in the Pieniny Klippen Belt – a case study of the Velykyi Kamenets’/Vilkhivchyk (Ukraine) and Biała Woda (Poland) sections

The geological position and geochemistry of the basaltic sill and tuffs occurring within the Berriasian–?Albian pelagic limestones of the Czorsztyn Succession are described. The volcanic rock succession of the Velykyi (= Veliky) Kamenets’/Vilkhivchyk (= Vulkhovchik, Vulhovchik, Olkhivchyk) sites is related to intra-plate submarine volcanism, which took place at the southeastern termination of the Pieniny Klippen Belt. This volcanism was probably associated with the Early Cretaceous opening of the Magura/Fore-Magura basinal system, bounded by the Silesian/Marmarosh and Czorsztyn palaeoridges to the north and south respectively. The alkaline volcanic rocks from the Velykyi Kamenets’/Vilkhivchyk sites are geochemically similary to the basaltic block from Biała Woda (Małe Pieniny Mts., Poland), which is an olistolith a few metres across within the Jarmuta conglomerates (Maastrichtian/Paleocene). This basaltic block was eroded from the frontal part of the Czorsztyn Nappe and was deposited in the uppermost part of the Grajcarek Succession at the southeastern margin of the Magura Basin

Middle Jurassic nodular limestones of the Czertezik Succession of the Pieniny Klippen Basin of Poland - facts and controversies

According to the present authors the decline of the Bajocian crinoidal limestone sedimentation in the Pieniny Klippen Basin corresponded to a general subsidence of the Czorsztyn Ridge which promoted the appearance of nodular limestones of the pelagic Ammonitico Rosso facies (Czorsztyn Limestone Fm., Niedzica Limestone Fm.). As proved by ammonite faunas recognized in the Czorsztyn, Niedzica and Czertezik successions, this replacement of the facies (sometimes related with hiatus) took place during the latest Bajocian. A different interpretation of stratigraphy of the crinoidal limestones is given by Birkenmajer (1977, 2007) who postulates a wider stratigraphical range of these deposits, in the Czertezik Succession, but also in the Czorsztyn Succession, from the Bajocian up to base or even end of the Callovian. According to this author the crinoidal limestones span in these two successions a large stratigraphical interval of the Middle Jurassic being partly a lateral equivalent of the nodular limestones of the Niedzica Limestone Fm. of the Niedzica Succession. The present authors investigations, based on new findings of ammonites (parkinsoniids—Parkinsonia (Parkinsonia) parkinsoni (Sow.), Parkinsonia cf. bomfordi Arkell), in the typical area of occurrence of the Czertezik Succession, indicate the presence of the uppermost Bajocian–lowermost Bathonian red nodular limestones of the Niedzica Limestone Formation, and along with older ammonite datings from the Czorsztyn Succession prove that the onset of sedimentation of the nodular limestones was almost coeval in the Czertezik Succession, the Czorsztyn Succession and the Niedzica Succession. Additionally, the ammonite fauna indicates that sedimentation of the crinoidal limestones in the Czertezik Succession took place during the Bajocian, similarly as in other successions of the Pieniny Klippen Belt. These new findings show that differences between the Czertezik Succession, and other successions of the Pieniny Klippen Belt are much smaller than hitherto proposed (Birkenmajer, 1959), and confirm an earlier interpretation of the present authors (Wierzbowski et al., 2004)

Palaeogeography of south-east Asia and its connection with distribution of Early Jurassic Lithiotis-type bivalve buildups according to Triassic/Jurassic mass extinction event

The separation of Laurasia and Gondwana, which was initiated by the Triassic break-up of Pangea, continued during Early-Middle Jurassic times. The origin of the narrow sea strait. so-called "Hispanic Corridor", took place between these two continents and connection of the Panthalassa Ocean (Proto-Pacific) and western (Alpine) Tethys gradually started in Early Jurassic, most probably in Sinemurian-Pliensbachian times. Recovery of marine fauna after Triassic/Jurassic mass extinction event was mainly marked by world-wide distribution of Lithiotis-type bivalve buildups. They indicate mainly shallow-marine/lagoon-type carbonate sedimentation and palaeogeographic/geodynamic regimes during break-up of Pangea in Pliensbachian-Early Toarcian times

Jurassic deposits of the Czertezik Succession of the Zamkowa Mt (Trzy Korony massif) in the Pieniny Mts

Middle to Upper Jurassic of the Zamkowa Mt (Trzy Korony massif) in the Pieniny Klippen Belt show special development of the Czertezik Succession. The section reveals very thick units of crinoidal limestones: the Smolegowa Limestone Formation grainstones abruptly laterally replaced by crinoidal-spiculitic grainstones of the Flaki Limestone Formation; these are overlain by strongly condensed pelagic limestones - in their uppermost part rich in planktonic foraminifers and radiolarians - with abundant detrital grains of quartz and dolomite, fragments of crinoidal limestones, and the glauconitic nodules (glaucony). Both the development of attaining large thicknesses of strongly facies contrasted crinoidal units supplied from overhanging "crinoid gardens", as well as the appearance of abundant grains in younger pelagic limestones, prove the synsedimentary faulting which produced an active tectonic scarp during the Bajocian and at the turn of Callovian and Oxfordian