Finsinger W.,Montpellier University |
Kelly R.,University of Illinois at Urbana - Champaign |
Fevre J.,Montpellier University |
Magyari E.K.,MTA MTM ELTE Research Group for Paleontology
Holocene | Year: 2014
Macroscopic charcoal records can be used to infer spatially explicit reconstructions of past fire history. However, a current deficiency in the charcoal-analysis toolbox has been the lack of a method to consider sampling variability and charcoal-particle area distributions for peak detection with charcoal-area records. We present a screening procedure specific for datasets comprising charcoal numbers and areas to screen the charcoal-area estimates with respect to the count sums. The rationale for screening charcoal-area peaks stems from the observation that although charcoal-area records can be more suitable in a statistical sense for peak detection (e.g. as established by the signal-to-noise index), charcoal-area peaks can be questionable if they are determined by just one or a few larger charcoal particles. Our method begins with a charcoal-area time series analysed by existing methods to identify peaks representing fire episodes. To screen these peaks, the method uses bootstrap resampling of charcoal-particle areas observed in a user-defined subsection of the record around each peak to obtain the range of likely charcoal areas for different counts. Peaks with total area within the likely range of bootstrapped samples (e.g. p > 0.05) are flagged as potentially unreliable, whereas samples with total area significantly greater than expected by chance are deemed robust indicators of past fire events. In an example application of the method to a charcoal record from Lake Brazi, Romania, several peaks failed to pass the screening suggesting that, as for count-based records, unscreened charcoal-area records may include spurious fire episodes and thus potentially underestimate past fire-return intervals. © The Author(s) 2014.
Kocsis L.,University of Lausanne |
Ozsvart P.,MTA MTM ELTE Research Group for Paleontology |
Becker D.,Jurassica Museum |
Ziegler R.,Staatliches Museum fur Naturkunde Stuttgart |
And 2 more authors.
Geology | Year: 2014
Terrestrial climatic data reflect variable and often conflicting responses to the global cooling event at the Eocene-Oligocene transition (ca. 34 Ma). Stable isotopic compositions of the tooth enamel of large, water-dependent, herbivorous terrestrial mammals are investigated here to better understand the European continental climate during the late Eocene- early Oligocene. High δ18OPO4 and δ13C values reflect a semiarid climate and ecosystem in the late Eocene. In the west-southwest region of Europe, these conditions prevailed until at least 33 Ma, after which it became more humid. A similar change was recorded north of the Alpine thrust, but it occurred 2 m.y. earlier. The north and west-southwest regions show a significant offset in δ18OPO4 composition between 35 and 31 Ma, indicating the influence of different air trajectories with different moisture sources (Atlantic versus Tethys). This also marks the presence of an orographic height in central Europe from the latest Eocene. After 31 Ma, a large drop in δ18OPO4 is registered, explained by altitude-induced fractionation on meteoric water isotopic composition. The related paleoaltitude change is estimated to be 1200 m, and the uplift could have taken place along the Alpine-Dinaridic orogenic system. © 2014 Geological Society of America.
Sztano O.,Eötvös Loránd University |
Sebe K.,University of Pécs |
Csillag G.,Geological and Geophysical Institute of Hungary |
Magyar I.,MOL Hungarian Oil and Gas Plc. |
Magyar I.,MTA MTM ELTE Research Group for Paleontology
Geologica Carpathica | Year: 2015
The floor of Lake Pannon covering the Pannonian Basin in the Late Miocene had considerable relief, including both deep sub-basins, like the Drava Basin, and basement highs, like the Mecsek Mts, in close proximity. The several km thick lacustrine succession in the Drava Basin includes profundal marls, basin-center turbidites, overlain by shales of basin-margin slopes, coarsening-upward deltaic successions and alluvial deposits. Along the margin of the Mecsek Mts locally derived shoreface sands and deltaic deposits from further away have been mapped so far on the surface. Recent field studies at the transition between the two areas revealed a succession that does not fit into either of these environments. A series of sandstone a few meters thick occurs above laminated to bioturbated clayey siltstone. The sandstone show normal grading, plane lamination, flat erosional surfaces, soft-sediment deformations (load and water-escape structures) and sharp-based beds with small reverse faults and folds. These indicate rapid deposition from turbidity currents and their deformation as slumps on an inclined surface. These beds are far too thick and may reveal much larger volumes of mass wasting than is expected on the 20-30 m high delta slopes; however, regional seismic lines also exclude outcropping of deep-basin turbidites. We suggest that slopes with transitional size (less than 100 m high) may have developed on the flank of the Mecsek as a consequence of lake-level rise. Although these slopes were smaller than the usually several hundred meter high clinoforms in the deep basins, they could still provide large enough inertia for gravity flows. This interpretation is supported by the occurrence of sublittoral mollusc assemblages in the vicinity, indicating several tens of meters of water depth. Fossils suggest that sedimentation in this area started about 8 Ma ago. © Geologica Carpathica 2015.
Magyari E.K.,MTA MTM ELTE Research Group for Paleontology |
Kunes P.,Charles University |
Jakab G.,Szent Istvan University |
Sumegi P.,University of Szeged |
And 4 more authors.
Quaternary Science Reviews | Year: 2014
To characterize Late Pleniglacial (LPG: 26.5-15kacalBP) and particularly Last Glacial Maximum (LGM: 21±2kacalBP) vegetation and climate, fossil pollen assemblages are often compared with modern pollen assemblages. Given the non-analogue climate of the LPG, a key question is how glacial pollen assemblages and thereby vegetation compare with modern vegetation. In this paper we present three LPG pollen records from the Carpathian Basin and the adjoining Carpathian Mountains to address this question and provide a concise compositional characterization of the LPG vegetation. Fossil pollen assemblages were compared with surface pollen spectra from the Altai-Sayan Mountains in southern Siberia. This area shows many similarities with the LPG vegetation of eastern-central Europe, and has long been considered as its best modern analogue. Ordination and analogue matching were used to characterize vegetation composition and find the best analogues. Our results show that few LPG pollen assemblages have statistically significant analogues in southern Siberia. When analogue pairings occur they suggest the predominance of wet and mesic grasslands and dry steppe in the studied region. Wooded vegetation types (continental and suboceanic hemiboreal forest, continental taiga) appear as significant analogues only in a few cases during the LGM and more frequently after 16kacalBP. These results suggest that the LPG landscape of the Carpathian Basin was dominated by dry steppe that occurred outside the river floodplains, while wet and mesic grasslands occurred in the floodplains and on other sites influenced by ground water. Woody vegetation mainly occurred in river valleys, on wet north-facing hillsides, and scattered trees were likely also present on the loess plateaus. The dominant woody species were Larix, Pinus sylvestris, Pinus mugo, Pinus cembra, Picea abies, Betula pendula/. pubescens, Betula nana, Juniperus, Hippophaë rhamnoides, Populus, Salix and Alnus. The pollen records suggest uninterrupted presence of mesophilous temperate trees (Quercus, Ulmus, Corylus, Fagus and Fraxinus excelsior) in the Eastern Carpathian Mountains throughout the LPG. We demonstrate that the LPG vegetation in this area was characterized by increasing grass cover and high frequency of wildfires. We conclude that pollen spectra over represent trees in the forest-steppe landscape of the LPG, furthermore pollen-based quantitative climate reconstructions for the LPG are challenging in this area due to the scarcity of modern analogues. © 2014 Elsevier Ltd.
Sumegi P.,University of Szeged |
Sumegi P.,Hungarian Academy of Sciences |
Magyari E.,MTA MTM ELTE Research Group for Paleontology |
Daniel P.,Biogal Pharmavit Rt |
And 2 more authors.
Quaternary International | Year: 2013
According to the findings of a complex sedimentological, geochemical, malacological and pollen study implemented on a core sequence of an alkaline lake (Fehér Lake), interstadials in the SE Great Hungarian Plain were characterized by increased boreal woodland cover during Marine Isotope Stage 2 (MIS 2: 29,700-14,500 cal BP). These interstadials were dated to 26,420-27,970, 23,185-24,880, and 18,810-20,770 cal BP, and correlate well with the Dansgaard-Oeschger (DO) interstadials 2 and 3 and the post LGM warm interval seen in the Greenland ice core oxygen isotope records. Intervening cold phases, on the other hand, were found between 24,880-26,420 and 20,770-23,185 cal BP, correlating with Heinrich event 2 and the LGM. These data overall confirm that millennial scale climate variability during Marine Isotope Stage 2 had profound effect on the terrestrial ecosystems in the continental interior of SE Europe, leading to periodic boreal woodland expansions and contractions and wildfires. © 2012 Elsevier Ltd and INQUA.
Price G.D.,University of Plymouth |
Fozy I.,Hungarian Natural History Museum |
Palfy J.,Eötvös Loránd University |
Palfy J.,MTA MTM ELTE Research Group for Paleontology
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2016
We present new carbon and oxygen isotope curves from sections in the Bakony Mts. (Hungary), constrained by biostratigraphy and magnetostratigraphy in order to evaluate whether carbon isotopes can provide a tool to help establish and correlate the last system boundary remaining undefined in the Phanerozoic as well provide data to better understand the carbon cycle history and environmental drivers during the Jurassic-Cretaceous interval. We observe a gentle decrease in carbon isotope values through the Late Jurassic. A pronounced shift to more positive carbon isotope values does not occur until the Valanginian, corresponding to the Weissert event. In order to place the newly obtained stable isotope data into a global context, we compiled 31 published and stratigraphically constrained carbon isotope records from the Pacific, Tethyan, Atlantic, and Boreal realms, to produce a new global δ13C stack for the Late Oxfordian through Early Hauterivian interval. Our new data from Hungary is consistent with the global δ13C stack. The stack reveals a steady but slow decrease in carbon isotope values until the Early Valanginian. In comparison, the Late Jurassic-Early Cretaceous δ13C curve in GTS 2012 shows no slope and little variation. Aside from the well-defined Valanginian positive excursion, chemostratigraphic correlation durSchning the Jurassic-Cretaceous boundary interval is difficult, due to relatively stable δ13C values, compounded by a slope which is too slight. There is no clear isotopic marker event for the system boundary. The long-term gradual change towards more negative carbon isotope values through the Jurassic-Cretaceous transition has previously been explained by increasingly oligotrophic condition and lessened primary production. However, this contradicts the reported increase in 87Sr/86Sr ratios suggesting intensification of weathering (and a decreasing contribution of non-radiogenic hydrothermal Sr) and presumably a concomitant rise in nutrient input into the oceans. The concomitant rise of modern phytoplankton groups (dinoflagellates and coccolithophores) would have also led to increased primary productivity, making the negative carbon isotope trend even more notable. We suggest that gradual oceanographic changes, more effective connections and mixing between the Tethys, Atlantic and Pacific Oceans, would have promoted a shift towards enhanced burial of isotopically heavy carbonate carbon and effective recycling of isotopically light organic matter. These processes account for the observed long-term trend, interrupted only by the Weissert event in the Valanginian. © 2016.
Pandolfi L.,Third University of Rome |
Gasparik M.,Hungarian Natural History Museum |
Magyar I.,MTA MTM ELTE Research Group for Paleontology
Geologica Carpathica | Year: 2016
Although the rhinoceros remains have high biochronological significance, they are poorly known or scarcely documented in the uppermost Miocene deposits of Europe. Several specimens collected from the Upper Miocene (around 7.0 Ma, Turolian) deposits of Kávás (Pannonian Basin, Western Hungary), previously determined as Rhinoceros sp., are revised and described in this paper. The postcranial remains of these specimens belong to "Dihoplus" megarhinus (de Christol) on the basis of the morphological and morphometric characters of humerus, radii, metacarpal and metatarsal elements. An overview of rhinoceros remains from several uppermost Miocene localities and the revision of the rhinoceros material from the Pannonian Basin suggest that "D." megarhinus spread during the latest Miocene from the Pannonian Basin towards Italy. The occurrences of this species in Western Hungary and Italy during the latest Miocene further imply that Rhinocerotini species were biogeographically segregated between Western, Southern and Central Europe. © 2016 Geologica Carpathica 2016.
Feurdean A.,Senckenberg Institute |
Feurdean A.,Romanian Academy of Sciences |
Spessa A.,Senckenberg Institute |
Spessa A.,Max Planck Institute for Chemistry |
And 6 more authors.
Quaternary Science Reviews | Year: 2012
Fire is recognized as a critical process with significant impacts on biota and the atmosphere. In this study, 11 micro- and macrocharcoal sedimentary records extracted from peat bogs and lakes at different elevations in the Carpathian region (in Hungary and Romania) were used to explore the patterns and the potential underlying mechanisms in biomass burning in this region during the last 15,000 years. Results from micro-charcoal and macro-charcoal data show similar trends in biomass burning and suggest that the major signal of both charcoal size-fragments relates mainly to local fires. Fire activity was low during the lateglacial, attained maximum values in the early Holocene (11,700-8000 cal. yr BP), become lower than present during the mid-late Holocene (8000-1000 cal yr BP), and increased again over the last 1000 years. The reconstructed spatial trends in biomass burning display different degrees of heterogeneity through time. Generally, there was more spatial similarity in fire activity across the study region during the lateglacial and early Holocene (15,000-8000 cal yr BP), followed by increased spatial heterogeneity from ca 8000 cal yr BP onwards. Biomass burning appears to have been primarily modulated by climate during both the lateglacial and Holocene, through its effect on vegetation productivity and therefore fuel availability (lateglacial), and fuel structure, moisture and flammability (the Holocene). Onsite human activities are likely to have provided an extra ignition source already in the early Holocene. However, evidence suggest that anthropogenic activities have markedly altered the natural trends in biomass burning from about 5500 yr BP (lowlands) and over the last 2000-1000 years (in the mountain environments), by either removing the biomass (in the lowlands) or igniting fire where it seldom occurs naturally (i.e., in the mountain environments). On the other hand, burning activity also appears coincident with significant changes in tree species compositions, indicating that fire has likely acted as a driving factor in forest dynamics. Results also suggest that peat deposits provide a more localized fire record than lakes, and that trends and patterns of change can be different even for sites situated close to each other. © 2012 Elsevier Ltd.
Voros A.,Hungarian Natural History Museum |
Voros A.,MTA MTM ELTE Research Group for Paleontology |
Kocsis A.T.,MTA MTM ELTE Research Group for Paleontology |
Kocsis A.T.,Eötvös Loránd University |
And 2 more authors.
Palaeogeography, Palaeoclimatology, Palaeoecology | Year: 2016
Brachiopods were severely hit by several mass extinctions which fundamentally shaped their long evolutionary history. After the devastating end-Permian extinction, the fate of the four surviving orders differed significantly during the Triassic and Jurassic. Two orders, the rhynchonellids and terebratulids are extant today, whereas spiriferinids and athyridids, which possess spiral brachidia, suffered heavy losses at the end of the Triassic and became extinct in the Early Jurassic Toarcian event. Although the doom of the spire-bearing orders has been thought to be related to physiological traits, extinction selectivity across the end-Triassic and Toarcian event has not been rigorously assessed previously, and the reasons for their demise at the later and lesser Toarcian event, rather than at the earlier and greater end-Triassic crisis remained unexplored. Using primarily the Paleobiology Database, we constructed diversity curves, estimated taxonomic rates, and assessed the temporal changes in geographic distribution of the two spire-bearing and two other orders in the Triassic-Jurassic interval. After shared trends and similar origination rates in the post-Permian recovery leading to a Late Triassic diversity maximum, the end-Triassic extinction was selective and preferentially eliminated the spire-bearers. In contrast to the rebound of rhynchonellids and terebratulids, spire-bearers failed to recover in the Early Jurassic, and their repeated selective extinction at the Toarcian event led to their final demise. The end-Triassic event also terminated the worldwide geographic distribution of spire-bearers, confining them to the Western Tethys, whereas the other groups were able to re-establish their cosmopolitan distribution. The morphologically diverse spire-bearers represent specialized adaptation, which further increased their extinction vulnerability compared to the other groups with conservative biconvex shell morphology. Another key difference is the physiological disadvantage of the fixed lophophore and passive feeding of spire-bearers, which became critical at times of increased environmental stress. The spire-bearing spiriferinids and athyridids were “dead clades walking” in the Early Jurassic and their disappearance in the Early Toarcian represents the last major, order-level extinction event for the brachiopods. © 2016 Elsevier B.V.
A taxonomic and nomenclatural revision of the historical brachiopod collection from the lower jurassic of yakacik (Ankara, Turkey), Housed in the geological and geophysical institute of Hungary [A magyar földtani és geofizikai intézetben őrzött törökországi (yakacik, Ankara) alsó-jura brachiopoda gyűjtemény revíziója]
Attila V.,MTA MTM ELTE Research Group for Paleontology
Foldtani Kozlony | Year: 2013
In this paper the Early Jurassic brachiopods from Yakacik (Turkey), housed at the Geological and Geophysical Institute of Hungary, are examined in detail in the framework of a taxonomic and nomenclatural revision of the 197 specimens collected by R. MILLEKER in 1911-1912, and shortly described by VADÁSZ (1913a, b, 1918). This revision resulted in the identification of 27 brachiopod taxa. They represent 16 genera and 23 nominal species; these are systematically described and documented by photographs and partly by serial sections. The new brachiopod taxa introduced and illustrated by VADÁSZ (1913a, b): Rhynchonellina anatolica and Waldheimia anatolica are re-evaluated and their taxonomic positions are updated as Suessia ? anatolica (VADÁSZ, 1913) and Aulacothyris anatolica (VADÁSZ, 1913), respectively. The Early Jurassic (Pliensbachian) brachiopod fauna of Yakacik shows a transitional character between two major faunal provinces: besides 4 endemic and 4 cosmopolitan species, 6 species have NW European, and 9 species have Mediterranean faunal affinity. © 2014 Hungarian Geological Society. All rights reserved.