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001-es BibID:	BIBFORM117261
035-os BibID:	(cikkazonosító)96 (WoS)001114788100002 (Scopus)85177833573
Első szerző:	Cserép Barbara
Cím:	Constraints on the pre-eruptive magma storage conditions and magma evolution of the 56-30 ka explosive volcanism of Ciomadul (East Carpathians, Romania) / Barbara Cserép, Máté Szemerédi, Szabolcs Harangi, Saskia Erdmann, Olivier Bachmann, István Dunkl, Ioan Seghedi, Katalin Mészáros, Zoltán Kovács, Attila Virág, Theodoros Ntafos, David Schiller, Kata Molnár, Réka Lukács
Dátum:	2023
ISSN:	0010-7999
Megjegyzések:	A detailed mineral-scale study was conducted on pumices of the latest, dominantly explosive eruption epoch (56-30 ka) of Ciomadul, the youngest, long-dormant volcano in eastern-central Europe for characterizing the magma storage system and for understanding better the changes in eruption style from efusive to explosive. The mineral cargo of dacitic pumices enables us to constrain the conditions of the pre-recharge crystal mush, the recharge magmas and the post-recharge magma prior to eruptions. A careful evaluation of the results yielded by various thermometers, barometers, oxybarometers, chemometers and hygrometers as well as direct comparison with experimental data were necessary to select the appropriate techniques and therefore to constrain the conditions for the Ciomadul magmatic system. Beneath the volcano, a felsic crystal mush body is inferred at 8-12 km depth comprising slightly oxidized (0.5-1.6 ?NNO), low-temperature (680-750 °C), highly crystalline magma. This zone is underlain by a deep magma storage zone with less evolved, hot (>900 °C) magma at 16-40 km depth. The dominantly explosive volcanism after the efusive eruptions (160-90 ka) can be explained by the ascent of distinct recharge magmas. They contained high-Mg (MgO>18 wt%) amphibole, which could have crystallized from ultrahydrous (H2O>8 wt%) magma at near-liquidus conditions. The rates of amphibole overgrowth and microphenocryst formation require weeks to months for the magma mixing and the eruption events. The hybridized melt became more oxidized and contained dissolved water in around 5.5 wt% at temperature of 790-830 °C calculated from the re-equilibrated Fe-Ti oxides. These magma properties along with the degree of crystallinity (27-38 vol% crystals) favored rapid magma ascent and an explosive style eruption. Thus, the strongly hydrous nature of the recharge magma in addition to the crystallinity and H2O content of the pre-eruption magma plays an important role in controlling the eruption style.
Tárgyszavak:	Természettudományok Földtudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Geothermobarometry Oxybarometry Pre-eruptive conditions Eruption style Recharge magma Magma reservoir Ciomadul
Megjelenés:	Contributions To Mineralogy And Petrology. - 178 : 12 (2023), p. 1-31. -
További szerzők:	Szemerédi Máté Harangi Szabolcs (1962-) (geokémikus, vulkanológus) Erdmann, Saskia Bachmann, Olivier Dunkl István Seghedi, Ioan Mészáros Katalin Kovács Zoltán Virág Attila (1986-) (geológus) Ntaflos, Theodoros Schiller, David Molnár Kata Lukács Réka
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001-es BibID:	BIBFORM116329
035-os BibID:	(Scopus)85175031969 (WoS)001092105000001 (cikkazonosító)83
Első szerző:	Molnár Kata
Cím:	Unravelling the pre-eruptive conditions of the rhyolitic Šumovit Greben lava dome from clinopyroxene-dominant glomeroporphyritic clots / Kata Molnár, Pierre Lahitte, Boglárka Döncző, Róbert Arató, János Szepesi, Zsolt Benkó, Sebastien Nomade, Jochen Gätjen, Stéphane Dibacto, Marjan Temovski
Dátum:	2023
ISSN:	0010-7999
Megjegyzések:	Detailed analyses of mineral composition and whole-rock geochemical data helped to unravel the volcanic plumbing system beneath the rhyolitic Sumovit Greben lava dome, the westernmost member of the Kozuf-Voras volcanic system (N. Macedonia). It is characterized by high SiO2 content (> 70 wt%) coupled with low MgO (< 1 wt%) and Sr (< 500 ppm) suggesting fractionation of clinopyroxene and plagioclase at depth forming a crystal mush and a crystal-poor rhyolitic lens by fractional crystallization and melt extraction on top of it. The crystal mush is composed of mainly clinopyroxene, biotite and plagioclase, whereas sanidine and plagioclase are the most abundant phenocrysts of the rhyolitic lens. The main dome forming event occurred at ca. 2.9 Ma, which sampled the crystal-poor rhyolitic lens. After a short quiescence time, an explosive eruption occurred depositing a massive lapilli tuff layer northwest of the lava dome, and an extrusion of a small-volume lava flow on the northern side of the lava dome at ca. 2.8 Ma. This latter sampled also the crystal mush, as it contains abundant glomeroporphyritic clots of clinopyroxene +/- plagioclase +/- biotite. The clinopyroxene phenocrysts are chemically homogeneous, their crystallization temperature is ca. 900(degrees)C representing the crystal mush, whereas the plagioclase and the sanidine crystallized at a lower temperature (ca. 790(degrees)C) representing the rhyolitic lens. Noble gas isotopic composition of the clinopyroxene indicate no mantle-derived fluids (< 0.5%) having an R/R-a of ca. 0.04 R-a. The rejuvenation of the system probably occurred due to implementation of mafic magma at depth leading to a heat transfer and partial melting of the cumulate. This led to crystallization of Ba-rich rims of the sanidine and An- and Sr-rich rims of the plagioclase. The crystal mush zone beneath Sumovit Greben might be connected to the nearby, more mafic volcanic centers, and the eruption of Sumovit Greben could have been the start of the last cycle in the lifetime of the Kozuf-Voras volcanic system.
Tárgyszavak:	Természettudományok Földtudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Rhyolite Clinopyroxene Noble gases Volcanic plumbing system Sanidine Ar/Ar dating
Megjelenés:	Contributions To Mineralogy And Petrology. - 178 : 11 (2023), p. 1-17. -
További szerzők:	Lahitte, Pierre Döncző Boglárka (1987-) (biológiatanár-földrajztanár) Arató Róbert Szepesi János Benkó Zsolt (1980-) (geológus) Nomade, Sebastien Gätjen, Jochen Dibacto, Stéphane Temovski, Marjan
Pályázati támogatás:	GINOP-2.3.2-15-2016-00009 GINOP GINOP-2.3.3-15-2016-00029 GINOP
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