The Upper Tithonian to Lower Berriasian carbonate sequence of the Getic Nappe system was studied near Golubac (eastern Serbia) using rock-magnetic and paleomagnetic methods to verify the age of the ...magnetization and to correlate magnetostratigraphy with biostratigraphy. A major part of the Dedina section shows the presence of authigenic goethite, hematite and magnetite as carriers of remagnetization. The youngest overprint, residing in goethite, sometimes carrying up to 90 % of natural remanent magnetization, was probably received after 18 Ma. The remagnetization residing in hematite and magnetite, attributed to the late Early Cretaceous collision, was obtained during long normal polarity Chron C34 (118–82 Ma). The mean direction implies a clockwise post-remagnetization rotation by about 57°. The normal (Dn) and reverse (Er) polarity components, heavily affected by the chemo-remanent magnetization overprint, can be tentatively interpreted in terms of polarity zones. Thus, the obtained data enabled a preliminary identification of M17r to M19n.2n magnetochrons. The correlation of magnetostratigraphy with biostratigraphy of the Dedina section contributes to the stratigraphic framework necessary for the definition of the Berriasian Global Boundary Stratotype Section and Point.
•Primary magnetization possibly heavily overprinted.•Tentative correlation to M17R to M19.2N magnetozones.•Large post-late Early Cretaceous clockwise rotation.
The Žilina-Hradisko borehole in Slovakia intersects a succession from the Cretaceous Hradisko formation to the Paleocene Hričovské Podhradie formation. In this paper, we mainly focus on the ...Cretaceous–Palaeogene (K–Pg) boundary interval, which is marked by an abrupt change in planktonic biota and magnetic properties. Micropalaeontological findings suggest a rapid change from a stable, oxygen-rich, oligotrophic environment during the Maastrichtian to an unstable, cooler environment with reduced oxygenation and evidence of biotic stress in the lowermost Danian strata. An abrupt change in the magnetite concentration in the same interval indicates increased detrital input and probably biogenic (soft) magnetite production. Evidence recorded in borehole with enhanced Hg input into the Maastrichtian Ocean suggests that the Deccan eruptions mostly occurred prior to the K–Pg boundary, whereas no volcanic Hg input was detected at the K–Pg boundary itself. Double peaks in multiple magnetic properties mark the Danian hyperthermal Dan-C2 event, which was characterised by a series of environmental changes, including enhanced terrigenous input, oxygen deficit, increased nutrient supply, high benthic productivity, and Parasubbotina acme. Prior to the Latest Danian event, foraminiferal assemblages were significantly affected by dissolution and oxygen depletion, followed by warming, water column stratification, and diversification of calcareous plankton groups. An increase in detrital input and nutrient export drove the productivity of deep-dwelling subbotinids and globanomalinids and were correlated with the mid-Paleocene biotic event (MPBE). The seafloor biota associated with the MPBE implies oxygen deficiency and the prevalence of benthic infauna. The Selandian–Thanetian strata markedly differ from planktonic foraminifera of older formations, with their rich content of large, diversified, and heavily calcified morozovellid and igorinid foraminifera, revealing the existence of water column stratification with surface-water productivity and meso- to oligotrophic conditions. The microfauna of ornate morozovellids and benthic biota from the lowermost formation implies the onset of environmental stress and CaCO3 dissolution during the Paleocene-Eocene Thermal Maximum (PETM).
•unravelling the end-Cretaceous to early Ypresian palaeoenvironmental events in the Alpine Tethyan realm•K-Pg boundary recorded by an abrupt change in microbiota and magnetic properties in response to stressful palaeoenvironments•predominantly pre-K-Pg volcanic Hg input•Dan-C2 event: double peaks in multiple magnetic properties, Parasubbotina acme, high benthic productivity•environmental perturbations and biotic changes connected to LDE, MPBE and PETM
An integrated study of micro- and nannoplankton distribution, O and C isotopes and palaeomagnetic record of nine Carpathian sections provided a key interpretation tool to characterize the ...Jurassic–Cretaceous (J/K) boundary transition. Biostratigraphy supported by saccocomids, radiolarians, calpionellids, dinoflagellates and nannofossils helped to distinguish biostratigraphic zones which could have been correlated both with stable isotopes and with magnetostratigraphy. The Alpina Event (lorica size change) accompanied by Nannoconus wintereri and N. steinmannii minor FO's designates the J/K boundary.
Sedimentary model in N Mediterranean Tethys margin consists of elevated blocks with slow (1–2 mm/ka) Rosso Ammonitico carbonate sedimentation separated by dysoxic depressions. Tectonic instability has been indicated by Upper Jurassic fluxoturbidites.
Late early Tithonian (M21n to M20r) saccocomid abundance increases with positive δ18O isotope ratios, similar excursion between M20n and M19r accompanied late Tithonian crassicollarian boom. The δ13C variation (>0.2‰) confronted with microplankton quantity variations: positive excursion occurred both during early Tithonian Saccocoma sp., and during late Tithonian calpionellid and nannoconid blooms. Higher up in the Berriasian “Maiolica” sequence, lighter δ13C values prevailed.
During late Tithonian (Praetintinnopsella-to earliest Crassicollaria zones; M20n1n to M19r), Saccocoma microfacies has been substituted by a calpionellid one. Reorganization of Tethyan oceanic currents during opening of the Hispanic corridor started planktonic carbonate particle „rain“ resulting in the Maiolica facies dominance. Sedimentary rate raised ten times. Calpionella alpina lorica size change event was synchronneous with FO's of Nannoconus wintereri and N. steinmannii minor and with negative δ18O trend of latest Tithonian (Colomi Subzone) warming. Expressiveness of eccentricity and obliquity cycles indicates climatic optimum conditions.
Early Paleogene events of the Alpine Tethys were considerably upgraded for the Western Carpathians. The Kršteňany KRS-3 core section provides high-resolution data from the Cretaceous-Paleogene (K/Pg) ...transition to Lutetian/Bartonian boundary. The Upper Cretaceous sequence started from terrestrial red-beds superposed by transgressive sediments with Abathomphalus mayaroensis. The K/Pg transition is inferred in a horizon with reworked Maastrichtian microfossils and earliest Danian species of Globigerinidae. Multiple redeposition with eugubina-rich clasts implies a storm erosion and resuspension of the post K/Pg sequence during P0 - Pα Zones (approx. 300 kyr). The early Danian microfauna was initially impoverished, later enriched by first praemuricids, and after the Latest Danian Event (LDE) diversified to angulate morozovellids, igorinids and fasciculiths. Paleocene bioevents and polarity chrons imply a radiation of planktic foraminifera during transgressive cycles in the late Danian (P1, C28n), Middle Selandian (P3b, C26r/n) and late Thanetian (P4c/P5, C25n/C24r), and vacant P/C zones either in regressive cycles or during unconformities in the early Danian (P1a/C28r), Danian/Selandian transition (P2/P3a, C27r/n) and middle Thanetian (P4b/C25r). The late Thanetian transgression (Th-2) led to replacement of Assilina-rich beds (SBZ 4) by Nummulites-bearing marls (SBZ 5) at the base of Ilerdian (= LFT). The Paleocene – Eocene transition is marked by Acarinina-rich marlstones with densely muricate species (Ac. acarinata) and excursion taxa (Ac. sibaiyaensis, D. araneus), which correspond to the Paleocene-Eocene Thermal Maximum (PETM). This horizon implies a warm-water productivity, eutrophication, humidity and upwelling activity (pteropods, diatoms). The hyperthermal conditions culminated at the beginning of the Early Eocene Climatic Optimum (EECO) with demise of morozovellids, intensification of hydrological cycles and enhanced continental input of siliciclastics, which progressed by accumulation of Ypresian nummulite banks and terminated by pelagic deposition with recovery of hispid morozovellids (E5 – E7 Zones, chron C23n - C22r). The lower Lutetian sequence reveals a post-EECO cooling by predominance of deep-dwelling habitats (subbotinids, turborotaliids, catapsydracids) and appearance of subtile morozovellids (M. gorrondatxensis), earliest globigerinathekids and another marker species of the E7 – E8 Zones (chron 22n - C21r). Late Lutetian warming (LLTM) is indicated by increased plankton productivity of mixed-layer habitats like strongly muricate species of anguloconical acarininids (Ac. topilensis, Ac. medizzai) and gracile species of morozovelloids (M. coronatus). The youngest part of the Kršteňany section belongs to the E11 Zone, indicating prior conditions of Middle Eocene Climatic Optimum (MECO) warming.
•The storm disturbed K/Pg sequence with reworked microfauna of boundary interzones (Ma/P0 – Pα).•Danian recovery of praemuricid foraminifers and their radiation (LDE).•Paleocene unconformities and biomagnetostratigraphic gaps (MPU, Th2).•Planktonic short-lived species and larger foraminifera turnover related to the PETM.•An unravelling of the Paleocene and Eocene global events in the Alpine Tethyan realm.
A flowstone section in the Račiška pečina Cave (Classical Karst, SW Slovenia) records multiple chronostratigraphic and palaeoclimatic proxies that can be correlated with other records on the global ...scale (Mediterranean region, Japan). Its upper part has an excellent record of the Matuyama/Brunhes (M/B) magnetic reversal. The M/B reversal zone, which is 6 mm in thickness, was detected by a high-resolution palaeomagnetic analysis of the sequence. An age model based on oxygen isotopic stratigraphy locates this quick transition in mid-MIS 19, between 777.9 and 777.2 ka, with the midpoint at 777.7 ka. The transition is marked by abrupt changes in stable isotopic compositions, trace element concentrations and flowstone fabrics that point to temperature and precipitation changes. Two distinct maxima in trace element concentrations at the beginning and the end of the M/B transition indicate two periods of higher precipitation, with increased washes of clay minerals into the cave. In addition, the stable isotopic (δ13C and δ18O) compositions indicate that significant cooling and high precipitation occurred during the M/B reversal within the generally warm MIS 19.
The Ochtiná Aragonite Cave (Western Carpathians) represents an unique natural phenomenon. It originated under particular lithological and hydrogeological conditions of the Ochtiná Karst in which ...several isolated lenses of Paleozoic crystalline limestone (marbles), partly metasomatically altered to ankerite, are enclosed by phyllites. Meteoric water seepage through non-carbonate rocks dissolved limestone and caused the oxidation of ankerite to Fe oxyhydroxides. Carbon dioxide produced during ankerite oxidation enhanced limestone dissolution. The maze cave consists of parallel fault-controlled linear passages and chambers interconnected by transverse horizontal passages. Phreatic and epiphreatic solution morphologies resulted from slowly moving or standing water. These include flat ceilings (
Laugdecken
), facets (planes of repose,
Facetten
), lateral notches, convection ceiling cupola-shaped depressions, and spongework-like hollows. Flat ceilings were developed in several altitude positions, each of them probably closely below the slightly oscillated water table. Primary phreatic cupola-shaped depressions, truncated by flat ceilings, represent relics of the oldest cavities (pre-Quaternary? to Early Pleistocene). Inward-sloping smooth facets were not developed only in passages with flat ceilings, but also in the passages and halls with a vaulted ceiling. The asymmetrical shape of cusped depressions above the facets were documented in detail by a high-resolution cave topography with terrestrial laser scanning and digital photogrammetry. Middle–Late Pleistocene accumulation phases, identified by magnetostratigraphy of cave sediments and U-series dating of speleothems, are associated with phreatic and later epiphreatic development. The deposition on the bottom bedrock began before 1.8 Ma. The Brunhes/Matuyama boundary (0.773 Ma) and Jaramillo magnetozone (0.990–1.071 Ma) were recorded in the profile in the Oválna chodba Passage. Slow depositional rate (~0.09 cm/kyr) calculated from magnetostratigraphy resulted from slow water movement in confined conditions in marbles completely enclosed by phyllites and no direct relation to the surface. Only occasionally turbid water was loaded in extremely fine-grained infiltration material and autochthonous Fe oxyhydroxides. The depositional rate in Mn-rich layer was much slower (~0.03 cm/kyr). Additional U-series dating confirmed that old aragonite generations (with ages about 500–450 ka and 143–121 ka) were partly corroded by repeated floods during Late Pleistocene humid episodes. Aragonite younger than 13.5 ka is not corroded.
Hypogene caves in the Plavecký hradný vrch Hill (Western Slovakia, Central Europe) were formed by waters ascending along faults in fractured Triassic carbonates related to the horst-graben ...structure at the contact of the Malé Karpaty Mountains and the NE part of the Vienna Basin. The Plavecká jaskyňa and Pec caves mostly contain horizontal passages and chambers with flat corrosion bedrock floors, fissure discharge feeders, wall water-table notches, replacement pockets, as well as a few other speleogens associated with sulfuric acid speleogenesis. The low-temperature sulfuric acid development phases of the Plavecká Jaskyňa are also indicated by the presence of sulfate minerals (i.e., gypsum and jarosite).Subaerial calcite popcorn rims were precipitated from water condensation at the edges of feeding fissures that were still active as thermal vents when the water table dropped. Hydrogen sulfide involved in the sulfuric acid speleogenesis was likely derived from anhydrites and/or hydrocarbon reservoirs with sulfate-saline connate waters in the fill of the adjacent Vienna Basin. It ascended to the surface along deep-rooted sub-vertical fault zones at the contact of the Vienna Basin with neighboring mountains. Three cave levels at 295 to 283 m asl in the Pec Cave, and five levels at 225 to 214 m asl in the Plavecká jaskyňa corresponded to phases of stable local erosional base levels in the bordering part of the Vienna Basin, most likely during periods of strongly decelerated and/or interrupted subsidence. Cave levels separated by vertical differences of only a few meters may also be related to the Pleistocene climatic cycles. The subhorizontal parts of the Pec Cave are probably of late Early Pleistocene age (˃0.99–1.07 Ma?). The two highest levels of the Plavecká jaskyňa developed during the early Middle Pleistocene (˃600 ka). Fine-grained sediments in the passage at 225 m asl with normal magnetic polarity contain jarosite. The middle level of the Plavecká jaskyňa at 220 m asl was formed in the mid-Middle Pleistocene, while the lower and lowermost levels formed in the late Middle Pleistocene (˃270 ka). The water table in the lowermost cave level probably dropped after the tectonic reactivation of the Podmalokarpatská zníženina Depression just in the front of a marginal horst structure of the Malé Karpaty Mountains.
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