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Mathias Harzhauser, Oleg Mandic, Matthias Kranner, Petra Lukeneder, Andrea K. Kern, Martin Gross, Giorgio Carnevale and Christine Jawecki

Abstract

Sarmatian and Pannonian cores, drilled at the western margin of the Vienna Basin in the City of Vienna, reveal a complex succession of marine and lacustrine depositional environments during the middle to late Miocene transition. Two Sarmatian and two Pannonian transgressive–regressive sequences were studied in detail. Identical successions of benthic faunal assemblages and similar patterns in magnetic susceptibility logs characterise these sequences. This allows a correlation of the boreholes over a distance of ~3.5 km across one of the major marginal faults of the Vienna Basin. Biostratigraphic data, combined with rough estimates of sedimentation rates, reveal large gaps between these sequences, suggesting that only major transgressions reached this marginal area. In particular, during the Sarmatian–Pannonian transition, the basin margin completely emerged and turned into a terrestrial setting for at least 600 ka.

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Austrian Journal of Earth Sciences

An international journal of the Austrian Geological Society

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Michal Kováč, Eva Halásová, Natália Hudáčková, Katarína Holcová, Matúš Hyžný, Michal Jamrich and Andrej Ruman

Abstract

Depositional sequences originating in semi-enclosed basins with endemic biota, partly or completely isolated from the open ocean, frequently do not allow biostratigraphic correlations with the standard geological time scale (GTS). The Miocene stages of the Central Paratethys represent regional chronostratigraphic units that were defined in type sections mostly on the basis of biostratigraphic criteria. The lack of accurate dating makes correlation within and between basins of this area and at global scales difficult. Although new geochronological estimates increasingly constrain the age of stage boundaries in the Paratethys, such estimates can be misleading if they do not account for diachronous boundaries between lithostratigraphic formations and for forward smearing of first appearances of index species (Signor-Lipps effect), and if they are extrapolated to whole basins. Here, we argue that (1) geochronological estimates of stage boundaries need to be based on sections with high completeness and high sediment accumulation rates, and (2) that the boundaries should preferentially correspond to conditions with sufficient marine connectivity between the Paratethys and the open ocean. The differences between the timing of origination of a given species in the source area and timing of its immigration to the Paratethys basins should be minimized during such intervals. Here, we draw attention to the definition of the Central Paratethys regional time scale, its modifications, and its present-day validity. We suggest that the regional time scale should be adjusted so that stage boundaries reflect local and regional geodynamic processes as well as the opening and closing of marine gateways. The role of eustatic sea level changes and geodynamic processes in determining the gateway formation needs to be rigorously evaluated with geochronological data and spatially-explicit biostratigraphic data so that their effects can be disentangled.

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Mădălina-Elena Kallanxhi, Ramona Bălc, Stjepan Ćorić, Szabolcs-Flavius Székely and Sorin Filipescu

Abstract

Sediments belonging to the Oligocene Vima Formation (located in the north-western part of the Transylvanian Basin, Romania) have been investigated for calcareous nannofossils content. Biostratigraphically, the sedimentary succession is late Rupelian–Chattian in age, belonging to the NP24 — Sphenolithus distentus and NP25 — Sphenolithus ciperoensis biozones, to CP19a — Cyclicargolithus floridanus and CP19b — Reticulofenestra bisecta Subzones and to the interval from CNO4 — Sphenolithus distentus/Sphenolithus predistentus CRZ to CNO5 — Sphenolithus ciperoensis TZ. The palaeoenvironment of the Fântânele section was reconstructed by means of calcareous nannofossils and statistics. Multivariate statistics were applied to the composition of autochthonous assemblages and the obtained clusters were used to assess the palaeoecological preferences of the nannofossils. We document changes from more stable open-marine regime, with temperate sea-surface temperatures interfering locally with influx of cooler water and enriched cool-nutrient supply for the late Rupelian–earliest Chattian (NP24), to shallower and possibly warmer near-shore marine eutrophic environment, with salinity fluctuations, increased terrigenous material run-off and freshwater influx for the remaining early Chattian (NP25).

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Franz Neubauer, Bianca Heberer, István Dunkl, Xiaoming Liu, Manfred Bernroider and Yunpeng Dong

Abstract

In the south-eastern Eastern Alps, the Reifnitz tonalite intruded into the Austroalpine metamorphic basement of the Wörthersee half-window exposed north of the Sarmatian–Pliocene flexural Klagenfurt basin. The Reifnitz tonalite is dated for the first time, and yields a laser ICP-MS U–Pb zircon age of 30.72±0.30 Ma. The (U–Th–Sm)/He apatite age of the tonalite is 27.6 ± 1.8 Ma implying rapid Late Oligocene cooling of the tonalite to ca. 60 °C. The Reifnitz tonalite intruded into a retrogressed amphibolite-grade metamorphic basement with a metamorphic overprint of Cretaceous age (40Ar/39Ar white mica plateau age of 90.7 ± 1.6 Ma). This fact indicates that pervasive Alpine metamorphism of Cretaceous age extends southwards almost up to the Periadriatic fault. Based on the exhumation and erosion history of the Reifnitz tonalite and the hosting Wörthersee half window formed by the Wörthersee anticline, the age of gentle folding of Austroalpine units in the south-eastern part of the Eastern Alps is likely of Oligocene age. North of the Wörthersee antiform, Upper Cretaceous–Eocene, Oligocene and Miocene sedimentary rocks of the Krappfeld basin are preserved in a gentle synform, suggesting that the top of the Krappfeld basin has always been near the Earth’s surface since the Late Cretaceous. The new data imply, therefore, that the Reifnitz tonalite is part of a post-30 Ma antiform, which was likely exhumed, uplifted and eroded in two steps. In the first step, which is dated to ca. 31–27 Ma, rapid cooling to ca. 60 °C and exhumation occurred in an E–W trending antiform, which formed as a result of a regional N–S compression. In the second step of the Sarmatian–Pliocene age a final exhumation occurred in the peripheral bulge in response to the lithospheric flexure in front of the overriding North Karawanken thrust sheet. The Klagenfurt basin developed as a flexural basin at the northern front of the North Karawanken, which represent a transpressive thrust sheet of a positive flower structure related to the final activity along the Periadriatic fault. In the Eastern Alps, on a large scale, the distribution of Periadriatic plutons and volcanics seems to monitor a northward or eastward shift of magmatic activity, with the main phase of intrusions ca. 30 Ma at the fault itself.

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Michal Kováč, Emő Márton, Tomáš Klučiar and Rastislav Vojtko

Abstract

The opening and evolution of the Western Carpathians Miocene basins was closely related to the north-eastward tectonic extrusion of the ALCAPA Mega-Unit lithosphere caused by the final stage of collision of the Eastern Alpine–Western Carpathian orogenic system with the European Platform and Alpine convergence with the Adria plate. The roll back effect of the oceanic or thinned continental crust of the Magura–Krosno realms, subduction below the front of the Carpathians in the north-east, east and relative plate velocities led to gradual stretching of the overriding micro-plates (defined as the ALCAPA and Tisza Dacia Mega-Unit). Diverse movement trajectories of the ALCAPA crustal wedge individual segments (Eastern Alps, Western Carpathians, and Northern Pannonian domain) were accompanied by several counter-clockwise rotational phases. Beside the interpreted Early Miocene “en-block” counter-clockwise rotation, most of the rotations in the Central Western Carpathians were caused by “domino-effect tectonics” inside strike-slip zones and took part in the basin opening, which was in most cases followed by rapid subsidence.

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Tomáš Mikuš, Julian Kondela, Stanislav Jacko and Stanislava Milovská

Abstract

The article presents the first description of a complete and continuous series from berthierite to garavellite sulphosalts in the Western Carpathians. Berthierite is a common main or accessory phase of Sb mineralizations in the Western Carpathians, and occurs at many localities and ore deposits as well. On the other side, garavellite or Bi-rich berthierite is a relatively rare accessory phase. The highest Bi content in garavellite reaches up to 38.04 wt. % which represents 0.90 apfu, and its crystallochemical formula can be written as Fe0.97Sb1.07Bi0.90S3.98. Raman band shifts were observed in the isomorphic berthierite–garavellite series. Garavellite occurs in the younger stages of sulphidic mineralization, and associates with tetrahedrite, berthierite, Bi-chalcostibite, Sb-bismuthinite, Bi-stibnite, ullmanite and cinnabarite. It creates irregular grains and veinlets in pre-existing tetrahedrite, or forms myrmekite intergrowths with chalcopyrite in tetrahedrite. Bi content in chalcostibite is up to 0.20 apfu. Besides the tetrahedrite, pre-existing sulphosalts are the members of the tintinaite–kobellite series, Bi-jamesonite and bournonite. The Sb/(Sb+Bi) ratio of minerals of the tintinaite–kobellite series varies from 0.37 to 0.80. The maximum content of Bi in jamesonite is up to 1.22 apfu. A vertical zonation at the ore vein body (mining levels 6 / 180 a.s.l., 8 / 80 a.s.l., 10 / 20 b.s.l.) is represented by the Sb decrease along with the Bi increase with increasing depth. Bi content continuously decreases during the older ore mineralization stage and Sb increases at the younger mineralization stage. Both of the stages have been enriched by Sb as well.

Open access

Ivana Carević, Morteza Taherpour-Khalil-Abad, Monika Mirković, Velimir Jovanović, Elham Mojtahedin and Dragana Vušković

Abstract

The occurrence of microfossil assemblage represented by calpionellids in close association with benthic foraminifera and encrusting Crescentiella morronensis is reported for the first time from the Upper Tithonian of NE Serbia. The biostratigraphic and sedimentological investigations were carried out on a 250 m thick carbonate succession in Jelenska Stena quarry cropping out along the Danube River Gorge in the border area of Serbian Carpatho–Balkanides and Romanian Southern Carphatians. On the basis of determined benthic foraminiferal taxa Textularia sp. cf. T. bettenstaedti and Everticyclammina praekelleri in the lower part of the succession and calpionellid association dominated by the representatives of calpionellid genera Tintinnopsella, Crassicollaria and Calpionella the carbonate succession is assigned to the Upper Tithonian. The scarcity of calpionellid zonal species prevents the nominal zones being recognized. Petrographic analysis of thin-sections led to the recognition of three basin microfacies types: bioclastic wackestone, bioclastic peloidal wackestone/packstone and mudstone. These microfacies characterize the SMF 3 and SMF 4 which indicate deposition in slope and toe-of-slope environments. This study extends the palaeogeographical distribution of Upper Tithonian calpionellids along the northern Tethyan margins. The investigated carbonate succession is compared with coeval strata from other northern Tethyan regions.

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Jarosław Majka, Mateusz P. Sęk, Stanisław Mazur, Bożena Gołębiowska and Adam Pieczka

Abstract

Tourmaline occurring in hornfelses from the eastern envelope of the Karkonosze Granite (Western Sudetes, Poland) reveals at least two stages of crystallization expressed by its complex zoning. The cores and mantles of the crystals probably grew during prograde metamorphism under intermediate pressure-temperature conditions reflected by increasing Mg, Ti and Ca. Outermost rims show enrichment in Al and Ca, indicating growth during contact metamorphism in the presence of an Al-saturating phase. The Ti-content in biotite indicates that the temperature of the contact metamorphic event did not exceed 650ºC. The presence of andalusite and the lack of garnet and cordierite also indicates pressure conditions of ~ 2-3 kbar, typical of the C1 bathozone of Carmichael (1978) or the P1 bathozone of Pattison (2001).

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Bambang Suharno, Fajar Nurjaman, Achmad Rifki, Robby Krisnaldo Elvin, Alif Ardiansyah Putra and Deni Ferdian

Abstract

The effect of coke and bituminous coal on the reduction of medium-grade manganese ore in ferromanganese production was investigated. Charges of 30 kg medium grade manganese ore, 12 kg limestone and varied amounts of coke and coal were smelted in a Submerged Electric Arc Furnace (SAF) at temperatures of 1300°C to 1500°C. The composition of the ferromanganese and the slag were determined by X-Ray Fluorescence. It was found that using coke as a single reductant resulted in a 96% yield of ferromanganese which was higher than by using coal either as a single reductant or in a mixture of coal and coke. It was also found that using coke as a single reductant resulted in the lowest specific energy consumption. Using coal as reductant produced ferromanganese containing high sulfur and phosphorus.