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Halmos L.,University of Szeged | Bozso G.,University of Szeged | Pal-Molnar E.,University of Szeged | Pal-Molnar E.,MTA ELTE Volcanology Research Group
Soil and Water Research

Adsorption properties of Cu, Ni, and Zn in alkaline sediments of Lake Fehér at Szeged (Hungary) were investigated. The effects of pollution of these three chosen phytotoxic elements in sodic sediments were primarily examined. These elements are strongly adsorbed in the soils and sediments with relatively high pH values for a long time without any influence on the geochemical processes. However, the salinization (indicated by the global climate change) of soils and sediments can strongly change the original geochemical status. For the adsorption experiments, the horizons with the highest organic matter contents were selected from two profiles. The pH, electrical conductivity (EC), particle size distribution, carbonate content, quality and quantity of organic matter, and clay mineral content of the selected samples were also determined. Efficiency of the adsorption is reduced in Cu > Zn>Ni and Cu>Ni > Zn order based on the calculated maximum and specific adsorption values. The adsorption properties of heavy metals are dependent on the content of soil constituents. The results showed that Cu has the highest but not the same affinity to each of the sorbent materials. Ni is strongly while Zn is less bounded to the organic matter. In most cases the results showed that the most effective fixative soil constituent is carbonate, followed by clay minerals and, last, organic matter regarding to the investigated elements. Source

Fintor K.,University of Szeged | Park C.,University of Hawaii at Manoa | Nagy S.,University of Szeged | Pal-Molnar E.,University of Szeged | And 2 more authors.
Meteoritics and Planetary Science

We report an occurrence of hexagonal CaAl2Si2O8 (dmisteinbergite) in a compact type A calcium-aluminum-rich inclusion (CAI) from the CV3 (Vigarano-like) carbonaceous chondrite Northwest Africa 2086. Dmisteinbergite occurs as approximately 10 μm long and few micrometer-thick lath-shaped crystal aggregates in altered parts of the CAI, and is associated with secondary nepheline, sodalite, Ti-poor Al-diopside, grossular, and Fe-rich spinel. Spinel is the only primary CAI mineral that retained its original O-isotope composition (Δ17O ~ -24‰); Δ17O values of melilite, perovskite, and Al,Ti-diopside range from -3 to -11‰, suggesting postcrystallization isotope exchange. Dmisteinbergite, anorthite, Ti-poor Al-diopside, and ferroan olivine have 16O-poor compositions (Δ17O ~ -3‰). We infer that dmisteinbergite, together with the other secondary minerals, formed by replacement of melilite as a result of fluid-assisted thermal metamorphism experienced by the CV chondrite parent asteroid. Based on the textural appearance of dmisteinbergite in NWA 2086 and petrographic observations of altered CAIs from the Allende meteorite, we suggest that dmisteinbergite is a common secondary mineral in CAIs from the oxidized Allende-like CV3 chondrites that has been previously misidentified as a secondary anorthite. © The Meteoritical Society, 2014. Source

Petrik A.,Eotvos Lorand University | Beke B.,Hungarian Academy of Sciences | Fodor L.,Hungarian Academy of Sciences | Lukacs R.,MTA ELTE Volcanology Research Group
Geologica Carpathica

Extensive structural field observations and seismic interpretation allowed us to delineate 7 deformation phases in the study area for the Cenozoic period. Phase D1 indicates NW-SE compression and perpendicular extension in the Late Oligocene-early Eggenburgian and it was responsible for the development of a wedge-shaped Paleogene sequence in front of north-westward propagating blind reverse faults. D2 is represented by E-W compression and perpendicular extension in the middle Eggenburgian-early Ottnangian. The D1 and D2 phases resulted in the erosion of Paleogene suites on elevated highs. Phase D2 was followed by a counterclockwise rotation, described in earlier publications. When considering the age of sediments deformed by the syn-sedimentary D3 deformation and preliminary geochronological ages of deformed volcanites the time of the first CCW rotation can be shifted slightly younger (~17-16.5 Ma) than previously thought (18.5-17.5 Ma). Another consequence of our new timing is that the extrusional tectonics of the ALCAPA unit, the D2 local phase, could also terminate somewhat later by 1 Myr. D4 shows NE-SW extension in the late Karpatian-Early Badenian creating NW-SE trending normal faults which connected the major NNE-SSW trending sinistral faults. The D5 and D6 phases are late syn-rift deformations indicating E-W extension and NW-SE extension, respectively. D5 indicates syn-sedimentary deformation in the Middle Badenian-early Sarmatian and caused the synsedimentary thickening of mid-Miocene suites along NNE-SSW trending transtensional faults. D5 postdates the second CCW rotation which can be bracketed between ~16-15 Ma. This timing is somewhat older than previously considered and is based on new geochronological dates of pyroclastite rocks which were not deformed by this phase. D6 was responsible for further deepening of half-grabens during the Sarmatian. D7 is post-tilt NNW-SSE extension and induced the deposition of the 700 m thick Pannonian wedge between 11.6-8.92 Ma in the southern part of the study area. © 2016 Geologica Carpathica 2016. Source

Batki A.,MTA ELTE Volcanology Research Group | Pal-Molnar E.,MTA ELTE Volcanology Research Group | Pal-Molnar E.,University of Szeged | Dobosi G.,MTA ELTE Volcanology Research Group | And 2 more authors.

Camptonite dykes intrude the rift-related Mesozoic igneous body of the Ditrǎu Alkaline Massif, Eastern Carpathians, Romania. We present and discuss mineral chemical data, major and trace elements, and the Nd isotopic compositions of the dykes in order to define their nature and origin. The dykes are classified as the clinopyroxene-bearing (camptonite-I) and clinopyroxene-free (camptonite-II) varieties. Camptonite-I consists of aluminian-ferroan diopside phenocrysts accompanied by kaersutite, subordinate Ti-rich annite, albite to oligoclase and abundant calcite-albite ocelli. Camptonite-II comprises K-rich hastingsite to magnesiohastingsite, Ti-rich annite, albite to andesine, abundant accessory titanite and apatite, and silicate ocelli filled mainly with plagioclase (An4-34).Age-corrected 143Nd/144Nd ratios vary from 0.51258 to 0.51269. The high εNd values of +4.0 to +6.1 which are consistent with intra-plate composition, together with light rare earth element (LREE), large ion lithophile element (LILE) and high field strength element (HFSE) enrichment in the camptonites is ascribed to the formation of small melt batches of a metasomatised sub-lithospheric mantle source. The presence of an asthenospheric 'high μ' ocean island basalt (HIMU-OIB)-type mantle component in the source region has also been revealed. A 1-4% degree of partial melting of an enriched garnet lherzolite mantle source containing pargasitic amphibole followed by fractionation is inferred to have been involved in the generation of the camptonites. They are deduced to be parental melts to the Ditrǎu Alkaline Massif. •Ditrǎu camptonites have been generated by 1-4% partial melting of an enriched mantle.•The source region is garnet lherzolite containing 4% of pargasitic amphibole.•The source enrichment is attributed to a sub-lithospheric metasomatic zone.•An asthenospheric HIMU-OIB-type mantle component was involved in the melt generation.•They are deduced to be parental melts to the Ditrǎu Alkaline Massif. © 2014 Elsevier B.V. Source

Harangi S.,MTA ELTE Volcanology Research Group | Harangi S.,Eotvos Lorand University | Lukacs R.,MTA ELTE Volcanology Research Group | Lukacs R.,University of Szeged | And 8 more authors.
Journal of Volcanology and Geothermal Research

High-spatial resolution zircon geochronology was applied to constrain the timescales of volcanic eruptions of the youngest, mostly explosive volcanic phase of Ciomadul volcano (Carpathian-Pannonian region, Romania). Combined U-Th and (U-Th)/He zircon dating demonstrates that intermittent volcanic eruptions occurred in a time range of 56-32. ka. The reliability of the eruption dates is supported by concordant ages obtained from different dating techniques, such as zircon geochronology, radiocarbon analysis, and infrared stimulated luminescence dating for the same deposits. The new geochronological data suggest that volcanism at Ciomadul is much younger (<. ca. 200. ka) than previously thought (up to 600. ka). A dominantly explosive volcanic phase occurred after an apparent lull in volcanism that lasted for several 10's of ka, after a period of lava dome extrusion that defines the onset of the known volcanism at Ciomadul. At least four major eruptive episodes can be distinguished within the 56-32. ka period. Among them, relatively large (sub-plinian to plinian) explosive eruptions produced distal tephra covering extended areas mostly southeast from the volcano. The 38.9. ka tephra overlaps the age of the Campanian Ignimbrite eruption and has an overlapping dispersion axis towards the Black Sea region. The wide range of U-Th model ages of the studied zircons indicates prolonged existence of a low-temperature (<. 800. °C) silicic crystal mush beneath Ciomadul. The main zircon crystallization period was between ca. 100 and 200. ka, coeval with the older, mostly extrusive lava dome building stage of volcanism. Even the youngest U-Th model ages obtained for the outermost 4. μm rim of individual zircon crystals predate the eruption by several 10's of ka. The zircon age distributions suggest re-heating above zircon saturation temperatures via injection of hot mafic magmas prior to eruption. Intermittent intrusions of fresh magma could play a significant role in keeping the intrusive silicic magmatic reservoir in a partially melted for prolonged period. The previous history of Ciomadul suggests that melt-bearing crystal mush resided beneath the volcano, and was rapidly remobilized after a protracted (several 10's of ka) lull in volcanism to trigger several eruptions in a comparatively short time window. This classifies Ciomadul as a volcano with 'Potentially Active Magma Storage' (PAMS) which we propose to be common among the seemingly inactive volcanoes in volcanic arc regions. The potential for reactivation of these systems should be included into volcanic hazard assessments. © 2015 Elsevier B.V. Source

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