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1.

001-es BibID:BIBFORM080901
Első szerző:Braun Mihály (vegyész, analitikus)
Cím:Using linear discriminant analysis (LDA) of bulk lake sediment geochemical data to reconstruct lateglacial climate changes in the South Carpathian Mountains / M. Braun, K. Hubay, E. Magyari, D. Veres, I. Papp, M. Bálint
Dátum:2013
ISSN:1040-6182
Megjegyzések:A multi-proxy approach is widely used for reconstructing climatic change in alpine lake sediments. This study applied bulk sediment geochemistry to reconstruct lateglacial and early Holocene climatic change in a glacial lake (Lake Brazi, 1740 m a.s.l.) in the Retezat Mts. (South Carpathians, Romania). The lowermost 1 m part of a 4.9-m long sediment core, covering the period between 9950 and 15,750 cal BP, was used for high resolution bulk analysis of major elements (Al2O3, SiO2, TiO2, CaO, MgO, K2O, Na2O, Fe2O3, MnO, SO3). Linear discriminant analysis (LDA) was used to compare a priori classified main chemical groups. Subsamples from the core were priory ordered to "warm" and "cold" groups respectively, according to their age and evidence of cold and warm events in the record, as suggested by proxy correlation with the lateglacial event stratigraphy of North Greenland Ice Core Project (NGRIP). The discriminant function was calculated using concentrations of Al2O3, TiO2, CaO, MgO, K2O, Na2O, Fe2O3, and MnO after log ratio transformation. Loss-on-ignition, silicon and sulphur concentrations were not used for the discriminant analysis, but regarded as comparison proxies for checking up the validity of outputs. Sediments deposited during "cold" and "warm" events were separated significantly by the LDA function; 85.1% of the originally grouped cases were correctly classified under the LDA analysis. The calculated discriminant scores indicated four "cold" and four "warm" events. Sediments ordered into the "warm" group contained larger amounts of organic matter and sulphur, while sediment samples of the "cold" group were characterized by the overall predominance of major oxides bound into inorganic silicates. The discriminant scores showed strong correlation with the NGRIP ?18O data (r = 0.8135) and with the pollen percentage sum of trees and shrubs (r = 0.9460). Loss-on-ignition showed a somehow weaker, but still conclusive linear relationship with the discriminant scores (r = 0.7505). Discriminant analyses of bulk sediment major oxide chemical data may be a useful tool to identify the impact of climatic events upon the nature and composition of materials delivered to a lake basin.
Tárgyszavak:Természettudományok Földtudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Quaternary International. - 293 (2013), p. 114-122. -
További szerzők:Hubay Katalin (1985-) (biológus, környezetkutató) Magyari Enikő (1973-) (biológus) Veres Dániel Papp István (1980-) (vegyész) Bálint Miklós
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2.

001-es BibID:BIBFORM080855
Első szerző:Haliuc, Aritina
Cím:Palaeohydrological changes during the mid and late Holocene in the Carpathian area, central-eastern Europe / Haliuc Aritina, Veres Daniel, Brauer Achim, Hubay Katalin, Hutchinson Simon M., Begy Robert, Braun Mihaly
Dátum:2017
ISSN:0921-8181
Megjegyzések:Multi-proxy, high-resolution analyses (lithological, geochemical, environmental magnetism) anchored by 2214Cdates, of a 5.53 m long sediment core from Lake Ighiel (Romanian Carpathians, central-eastern Europe) allowedthe reconstruction of key local, catchment-lacustrine dynamics and an appraisal of palaeohydrological andpalaeoclimatic gradients acting regionally over the last 6000 years. Thefirst sedimentological phase of the recordfrom 6030 to 4200 cal yr BP is characterised by low productivity and high detrital input indicating surface runoffprocesses due to enhanced rainfall. This interpretation is in agreement with other hydrological reconstructionsreporting increased precipitation also in CE Europe, NE Mediterranean and also inferred summer and winter lat-itudinal temperature gradients (LTG) (as defined by Davis and Brewer, 2009), showing a strong connectivity be-tween basin-lacustrine dynamics and the establishment of the dominant, Atlantic atmospheric circulationpattern in the area. The lacustrine system was more stable between 4200 and 2500 cal yr BP when clastic inputsdiminished and biological productivity increased. During this interval, the coherence of Lake Ighiel's multi-century detrital events, identified in a range of proxy-data (albeit different in frequency and magnitude), withflood activity in central Europe (the Alps) suggests a common moisture forcing (Atlantic and periodically Medi-terraneaninfluences). Incontrast, different reconstructionsfrom the NEMediterraneanindicate a distinct NW-SEhydro-climatic gradient. A more complex and variable trend is depicted in Lake Ighiel sedimentation during thelast ~2500 years showing a variable detrital trend likely reflecting an intriguing hydrological pattern which is inagreement with intervals of increased aridity phases during a generally moister period. Comparing our sedimen-tological results with published pollen records from the nearby area clearly indicates anthropogenic imprintsduring the Dacian-Roman Period and especially from the Middle Ages towards the present. The ~6000-yearlong sedimentary record of Lake Ighiel contributes to our understanding of mid and late Holocenepalaeohydrological changes in the Carpathians and highlights the importance of latitudinal gradients in drivinghydrological variability in continental Europe.
Tárgyszavak:Természettudományok Földtudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:Global And Planetary Change. - 152 (2017), p. 99-114. -
További szerzők:Veres Dániel Brauer, Achim Hubay Katalin (1985-) (biológus, környezetkutató) Hutchinson, Simon M. Begy, Robert Braun Mihály (1966-) (vegyész, analitikus)
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3.

001-es BibID:BIBFORM073714
Első szerző:Hubay Katalin (biológus, környezetkutató)
Cím:Holocene environmental changes as recorded in the geochemistry of glacial lake sediments from Retezat Mountains, South Carpathians / Hubay Katalin, Braun Mihály, Buczkó Krisztina, Pál Ilona, Veres Daniel, Túri Marianna, Biró Tamás, Magyari Enikő
Dátum:2018
ISSN:1040-6182
Megjegyzések:Sediment cores obtained from two deep (>15?m) glacial lakes were analyzed in context of terrestrial vegetation development and in-lake processes from the Retezat Mountains (Southern Carpathians, Romania). Only the Holocene parts were chosen for study for testing what is the connection between geochemical changes and biotas around and in the lakes. The lakes are situated at slightly different altitudes on the northern (Lake Gales, 1990 m a.s.l.) and southern slope (Lake Bucura, 2040 m a.s.l.), respectively. Changes in geochemical composition were relatively low amplitude during the studied period (10,300?1790 and 10,300?695?cal?yr BP) in both lakes, but the applicability of enrichment factor (EF) for geochemical elements and diatom ecological traits (guilds) in paleoecological reconstruction were demonstrated in this paper. The main changes have been observed at ca. 10,670?9000, 6500 and 3100?cal?yr BP in geochemistry, vegetation and siliceous algal assemblages. Catchment soil stabilization was apparent from ?9000?cal?yr BP onwards, in-lake and terrestrial productivity was the highest between 9000 and 6500?cal?yr BP and human impact became the dominant driver in both terrestrial vegetation and sediment geochemical changes and in-lake processes over the last ?3400 years in both lakes. The geochemical record displayed frequent erosional events within the Holocene. The strongest soil erosions clustered around 6500?7400 and 3200-900?cal?yr BP.
Tárgyszavak:Természettudományok Környezettudományok idegen nyelvű folyóiratközlemény külföldi lapban
holocén
környezetváltozás
geokémia
szediment
Megjelenés:Quaternary International. - 477 (2018), p. 19-39. -
További szerzők:Braun Mihály (1966-) (vegyész, analitikus) Buczkó Krisztina (1962-) (biológus) Pál Ilona Veres Dániel Túri Marianna (1988-) (geográfus-geoinformatikus) Biró Tamás Magyari Enikő (1973-) (biológus)
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4.

001-es BibID:BIBFORM084481
Első szerző:Karátson Dávid (földrajz-biológia tanár)
Cím:Morphometrical and geochronological constraints on the youngest eruptive activity in East-Central Europe at the Ciomadul (Csomád) lava dome complex, East Carpathians / Karátson Dávid; Telbisz Tamás; Harangi Szabolcs; Magyari Enikő; Dunkl István; Kiss Balázs; Jánosi Csaba; Veres Dániel; Braun Mihály; Fodor Emőke; Biró Tamás; Kósik Szabolcs; Hilmar von Eynatten; Ding Lin
Dátum:2013
ISSN:0377-0273
Megjegyzések:The timing of Late Pleistocene volcanic activity of the Ciomadul (Csomád) dacitic lava dome complex, site of the youngest eruptions in the Carpathians, has been constrained by morphometric analysis and radiometric chronology. Peléan domes and asymmetric domes/coulées built up the volcano, including the central edifice that hosts the youngest twin craters ofMoho₀s (Mohos) peat bog and lake St. Ana (Szent Anna). A comparative digital elevationmodel (DEM)-basedmorphometric analysis of lava domes (29worldwide examples including 5 domes from Ciomadul) shows that it is themean slope of the upper dome flank that correlates best with age. Although the logarithmic relationship is only moderately strong (R=0.80), slope characteristics of the Ciomadul domes fit to those of 10?100 ka old domes. These young ages contradict the previous K/Ar dates giving as old as 1 Ma ages on a number of domes, but are supported by ongoing U?Pb and (U?Th)/He zircon dating. The latter methods constrain the whole volcanic activity to the past 250 ka and the emplacement of most lava domes within the period of 150?100 ka. The volcanism at Ciomadul produced alternating effusive and explosive eruptions including lava dome collapses and successive crater formations. The latest, possibly subplinian explosive event formed the wellpreserved St. Ana crater. Radiocarbon dating of organic remains from a sediment core that reached 11 m into the lacustrine infill of St. Ana suggests that the crater was formed prior to 26,000 years BP
Tárgyszavak:Természettudományok Földtudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Lava dome morphometry
DEM analysis
Carpathian volcanism
U-Pb and (U-Th)/He geochronology
Paleolimnology
Megjelenés:Journal Of Volcanology And Geothermal Research. - 255 : 1 (2013), p. 43-56. -
További szerzők:Telbisz Tamás Harangi Szabolcs (1962-) (geokémikus, vulkanológus) Magyari Enikő (1973-) (biológus) Dunkl István Kiss Balázs Jánosi Csaba Veres Dániel Braun Mihály (1966-) (vegyész, analitikus) Fodor Emőke Biró Tamás Kósik Szabolcs Eynatten, Hilmar von Ding, Ling
Pályázati támogatás:Hungarian National Research Funds T68587
Egyéb
Hungarian National Research Funds NF101362
Egyéb
SOPHRD 2007?2013 project no./POSDRU/89/1.5/S/60189
Egyéb
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5.

001-es BibID:BIBFORM084456
Első szerző:Magyari Enikő (biológus)
Cím:A 13,600-year diatom oxygen isotope record from the South Carpathians (Romania): Reflection of winter conditions and possible links with North Atlantic circulation changes / Magyari Enikő Katalin, Demény Attila, Buczkó Krisztina, Kern Zoltán, Vennemann T., Fórizs István, Vincze Ildikó, Braun Mihály, Kovács István János, Udvardi Beatrix, Veres Dániel
Dátum:2013
ISSN:1040-6182
Megjegyzések:This study provides a continuous lateglacial and Holocene record of diatom silica oxygen isotope changes (?18ODIAT) in a subalpine lake sediment sequence obtained from the Retezat Mts (Taul dintre Brazi, 1740 m a.s.l.). This through-flow, shallow, high-altitude lake with a surface area of only 0.4 ha has short water residence time and is predominantly fed by snowmelt and rainwater. Its ?18ODIAT record principally reflects the oxygen isotope composition of the winter and spring precipitation, as diatom blooms occur mainly in the spring and early summer. Hence, changes in ?18ODIAT are interpreted as seasonal scale changes: in the amount of winter precipitation. Low oxygen isotope values (27-28.5?) occurred during the lateglacial until 12,300 cal BP, followed by a sharp increase thereafter. In the Holocene ?18ODIAT values ranged from 29 to 31? until 3200 cal BP, followed by generally lower values during the late Holocene (27?30?). Short-term decreases in the isotopic values were found between 10,140-9570, 9000?8500, 7800?7300, 6300?5800, 5500?5000 and at 8015, 4400, 4000 cal BP. After 3200 cal BP a decreasing trend was visible with the lowest values between 3100?2500 and after 2100 cal BP The general trend in the record suggests that contribution of winter precipitation was generally lower between 11,680 and 3200 cal BP, followed by increased contribution during the last millennia.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Quaternary International. - 293 (2013), p. 136-149. -
További szerzők:Demény Attila Buczkó Krisztina (1962-) (biológus) Kern Zoltán Vennemann, Torsten Fórizs István Vincze Ildikó Braun Mihály (1966-) (vegyész, analitikus) Kovács István János Udvardi Beatrix (Budapest) Veres Dániel
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6.

001-es BibID:BIBFORM080850
035-os BibID:(cikkazonosító)104112
Első szerző:Vincze Ildikó
Cím:Paleoclimate reconstruction and mire development in the Eastern Great Hungarian Plain for the last 20,000 years / Vincze Ildikó, Finsinger Walter, Jakab Gusztáv, Braun Mihály, Hubay Katalin, Veres Daniel, Deli Tamás, Szalai Zoltán, Szabó Zoltán, Magyari Enikő
Dátum:2019
ISSN:0034-6667
Megjegyzések:We present the reconstruction of mire vegetation changes and fire history recorded in a continuous sediment profile that spans the last 20,000 cal yr BP from the Late Pleniglacial to Holocene in North-eastern Hungary. We also aimed to reveal past climate changes by using ecological requirements of specific aquatic plants as summer temperature indicators. Our results suggest the formation of a mesotrophic mire around 20,000 cal yr BP with brown moss, Betula sp. and Selaginella selaginoides cover beside the occurrence of Phragmites australis, Typha latifolia and T. angustifolia suggesting base-rich fen and tundra-like wet-ground habitats on the lakeshore. This community shifted to reed dominated swamp at c. 18,300 cal yr BP with inferred min. July temperatures of 12-15.7 °C. pinus sp., Betula nana, B. pendula/pubescens, Hippuris vulgaris and P. australis dominated until 16,600 cal yr BP pointing to shallow muddy stagnant water and colder climatic conditions than in the preceding interval. The most warmth-demanding species, T. latifolia and T. angustifolia indicated July mean temperatures > 14-15.7 °C soon after the LGM. The formation of biogenic carbonate also started at an early stage; major accumulation occurred between 15,200 and 10,000 cal yr BP. In the Early Holocene, environmental indicator species (e.g., Phragmites australis and T. latifolia) pointed to warmer and shallower conditions, while the late Holocene was characterized by strong eutrophication and reed swamp dominance on the lakeshore. Elevated macrocharcoal concentration, wood fragments and remains of Typha species suggested frequent local fires and dry mire surface conditions during the last 1700 years.
Tárgyszavak:Természettudományok Földtudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:Review Of Palaeobotany And Palynology. - 271 (2019), p. 1-21. -
További szerzők:Finsinger, Walter Jakab Gusztáv Braun Mihály (1966-) (vegyész, analitikus) Hubay Katalin (1985-) (biológus, környezetkutató) Veres Dániel Deli Tamás Szalai Zoltán Szabó Zoltán Magyari Enikő (1973-) (biológus)
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