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Large quantities of Cretaceous Fe-oxidising bacteria (FeOB) are documented here for the first time in carbonate injection dykes. These injection dykes occur in fissures of a Palaeozoic metamorphic complex in the Geresd Hills, Hungary, and are made up of microlaminated haematitic carbonate that contain very well preserved helical FeOB stalk fossils similar to recent iron-oxidising Gallionella and Mariprofundus. The presence of filament clusters with semi-parallel textures suggests aerotactic bacterial cell movements. Fractal analysis of the filament clusters showed higher fractal dimension values (D f ∼ 1.9) compared to the typical fractal dimension values of the texturally similar, but inorganic Diffusion-Limited Aggregation (DLA) structures (D f ∼ 1.7). This finding is interpreted to suggest that the observed filamentous texture is of microbial origin. Cretaceous basaltic intrusions that penetrated the gold-bearing pyritic metamorphic basement launched a low-temperature flow of reductive iron-rich fluids. Well‑oxygenated bottom waters percolated through thin pelagic sediments and picked up ferrous iron from the pyritic metamorphic bedrock and made it available for the Fe-oxidising microbes. Reactivation of a major fault zone (Mecsekalja Zone) resulted in the development of extensional faults in the metamorphic basement beneath the seafloor. Pelagic carbonate sediments with FeOB mats were drawn into these fissures, forming a network of injection dykes. This study shows that fractal dimension analysis and directional analysis may be a helpful method to differentiate FeOB textures from inorganic textures in ancient rocks. The presented results are expected to provide useful analogues to aid the reconstruction of similar palaeoenvironments worldwide. • First globally: Cretaceous iron bacteria in injection dykes. • FeOB's stalks suggest aerotactic motion. • Fractal dimensions distinguish FeOB from inorganic structures. • Submarine pyritic rocks served as electron donors for Fe-bacteria. • Pelagic sediment drawn into seismic shock induced fractures to form injection dykes. [ABSTRACT FROM AUTHOR]

Abstract: In the Early Cretaceous, the continental rift basin of the Mecsek Mts. (Hungary), was situated on the southern edge of the European plate. The opening of the North Atlantic Ocean created a dilatational regime that expanded to the southern edge of the European plate, where several extensional basins and submarine volcanoes were formed during the Early Cretaceous epoch. Permanent seaquake activity caused high swell events during which a large amount of terrestrial wood fragments entered into submarine canyons from rivers or suspended woods which had sunk into the deep seafloor. These fragments created extended wood-fall deposits which contributed large-scale flourishing of numerous burrowing thalassinid crustaceans. Twelve different thalassinid coprolite ichnospecies can be found in the Berriasian–Hauterivian volcano-sedimentary formations. According to the seladonitic crustacean burrows which associated with framboidal pyrite containing Zoophycos and Chondrites ichnofossils (i.e. a “fodinichnia” trace fossil association), the bottom water was aerobic and the pore water was anaerobic; in the latter sulfate reduction occurred. The preservation of wood fragments around thalassinid burrows can be explained by rapid sedimentation related to turbidity currents. Due to the low temperature hydrothermal circulations of seawater, large amounts of iron were released from intrusive, pillowed basaltic sills; these sills intruded into soft, water-saturated sediments containing large amounts of thalassinid excrement. In the coprolites can be found idiomorphic mineral particles originating from the basalts, and coprolites can often be found in peperitic interpillow sediments. This indicates that the life-activity of the decapoda crustaceans in many Lower Cretaceous occurrences initially preceded the first magmatic eruptions. The paroxysm of the rift volcanism took place during the Valanginian age, when some submarine volcanoes emerged above sea level, reaching a maximum height of 300m (above sea level); from these volcanoes further terrestrial plant debris got into the basin. Hydrothermal vents, which periodically occurred around basaltic bodies until the Hauterivian, could have contributed to the creation of favourable temperature or nutritional conditions for some decapoda crustaceans – e.g the recently described new callianassid (Nihonotrypaea thermophila), which is known only from hydrothermally infuenced habitats. Around the intrusive pillow basalts, hydrothermal circulation of oxygenated seawater occured and thick seladonitic and goethitic fills formed along the cracks and cavities of pillowed basalts. When oxidized, sulfate-rich fluids passed into the crustacean coprolite-rich, reductive and anaerobic interpillow sediments, these fluids underwent an intensive sulfate reduction. This was primarily due to termophil sulfate reducers which as proved by the negative sulfur isotope values (−35.9‰ and −28.0‰ δ 34S) of sulfidic hydrothermal chimneys which contain framboidal pyrite and which were formed between the pillow basalts. The largest chimney structure reached a height of 1m, with a mass of about 150kg. The sulfide phase is characterized by Mo enrichments up to 511ppm. The fluid inclusion measurements from the calcitic precipitations of the sulfide chimneys indicate low temperature (~129°C) hydrothermal activity, and the salinity of the primary fluid inclusions proves the seawater origin of the hydrothermal fluids. In some thalassinid crustacean coprolite rich interpillow sediments and in the cracks of some hydrothermal calcite, there is the presence of black, lustrous bitumine (gilsonite) which is the distillation product of hydrothermal petroleum formed mainly by the coprolites. Hydrothermal circulations of oxygenated seawater caused subsequent oxidation of the sulfidic, interpillow sediments and chimneys; these were altered to form goethite. Due to the short-period of the hydrothermal activity among the intrusive pillowed basalts, sulfidized interpillow sediments could not be oxidized completely. The texture of the goethitic iron ore (as an interpillow sediment) is network-like and dentritic, which is very similar to the iron-oxidic and microbial textured sediments of the Juan de Fuca Ridge. The dendritic iron-oxide-hydroxide particles which were involved in this study are not hollow and exceed the size-domain characteristic for bacterial products. However, in some cases hollow- and tube-like particles having a diameter of 1.2–1.5μm can refer to the activity of the Sphaerotilus–Leptothrix iron-oxidizer bacterial group. [Copyright &y& Elsevier]

Ochre is the common archaeological term for prehistoric pigments. It is applied to a range of uses, from ritual burials to cave art to medications. While a substantial number of Palaeolithic paint mining pits have been identified across Europe, the link between ochre use and provenance, and their antiquity, has never yet been identified. Here we characterise the mineralogical signature of core-shell processed ochre from the Palaeolithic paint mining pits near Lovas in Hungary, using a novel integration of petrographic and mineralogical techniques. We present the first evidence for core-shell processed, natural pigment that was prepared by prehistoric people from hematitic red ochre. This involved combining the darker red outer shell with the less intensely coloured core to efficiently produce an economical, yet still strongly coloured, paint. We demonstrate the antiquity of the site as having operated between 14–13 kcal BP, during the Epigravettian period. This is based on new radiocarbon dating of bone artefacts associated with the quarry site. The dating results indicate the site to be the oldest known evidence for core-shell pigment processing. We show that the ochre mined at Lovas was exported from the site based on its characteristic signature at other archaeological sites in the region. Our discovery not only provides a methodological framework for future characterisation of ochre pigments, but also provides the earliest known evidence for “value-adding” of products for trade. [ABSTRACT FROM AUTHOR]

We report here for the first time the composition and mineralogical studies on a new meteorite, which was found in August 2012 near the village of Csátalja, Hungary (46°0׳21׳׳N; 18°59׳27׳E). The Csátalja meteorite is classified as a H4–5 ordinary chondrite with shock stage S2 and a degree of weathering W1 and the total mass is 15 kg. The Csátalja meteorite is characterized by well-defined chondrules composed either of olivine or pyroxene. X-ray diffractogram shows the primary phases olivine, pyroxene, kamacite, and albite. Metal particles were extracted from the bulk powdered samples exhibit only kamacite and small amounts of the intergrowth taenite/kamacite. Raman spectra of forsterite indicate that Csátalja meteorite suffered from relatively low shock pressure regime. The texture of chondrules varies from nonporphyritic (e.g., barred olivine, radial pyroxene) to porphyritic ones (e.g., granular olivine as well as olivine pyroxene). The meteorite name has not yet approved by the Nomenclature Committee of the Meteoritical Society. [ABSTRACT FROM AUTHOR]