10 Abstract Ciomadul is the youngest volcano in the Car-11 pathian-Pannonian region produced crystal-rich high-K 12 dacites that contain abundant amphibole phenocrysts. The 13 amphiboles in the studied dacites are characterized by large 14 variety of zoning patterns, textures, and a wide range of 15 compositions (e.g., 6.4-15 wt% Al 2 O 3 , 79-821 ppm Sr) 16 often in thin-section scale and even in single crystals. Two 17 amphibole populations were observed in the dacite: low-Al 18 hornblendes represent a cold (\800°C) silicic crystal 19 mush, whereas the high-Al pargasites crystallized in a hot 20 ([900°C) mafic magma. Amphibole thermobarometry 21 suggests that the silicic crystal mush was stored in an upper 22 crustal storage (*8-12 km). This was also the place where 23 the erupted dacitic magma was formed during the remo-24 bilization of upper crustal silicic crystal mush body by hot Author Proof We investigate the implications of our study for using 91 amphibole to constrain the subvolcanic plumbing systems 92 of andesitic to dacitic arc volcanoes in general. Finally, we 93 discuss the origin, conditions, and processes lead to com-94 monly observed bimodal amphibole populations in inter-95 mediate mixed magmas erupted at composite arc 96 volcanoes. Our study highlights that different amphibole 97 thermobarometers can produce essentially different results, 98 which may lead to false interpretations on the magma 99 evolution and architecture of the magma storage system 100 without clear textural control and crystal growth stratigra-101 phy. We point out the deficiency of the Ridolfi's thermo-102 barometric model that yields always the same p-T 103 evolution path for amphiboles along their stability curve. Geological setting105 Ciomadul volcano is located at the southeastern edge of the 106 Carpathian-Pannonian region, and this is the youngest 107 volcano of this area (Szakács and Seghedi 1995; Szakács 108 et al. 2002;Vinkler et al. 2007;Harangi et al. 2010; Kar-109 átson et al. 2013). It is found at the southern termination of 110 the Cȃlimani-Gurghiu-Harghita (CGH) andesitic-dacitic 111 volcanic chain (Fig. 1) 120 et al. 1987;Szakács et al. 1993; Mason et al. 1996). Vol-121 canic eruptions in Ciomadul could have started around 122 200 ka, and the last volcanic event occurred at 123 31,000 ± 260 cal BP. Initially, the volcanism was mostly 124 effusive and a lava dome complex developed called here 125 ''old Ciomadul.'' Later, the volcanic activity became more 126 explosive and as a result of successive phreatomagmatic 127 and subplinian eruptions, the edifice of the ''old Ciomadul'' 128 was partially destroyed and two deep explosive craters 129 were formed (Szakács and Seghedi 1995; Karátson et al. 130 2013). The erupted magma remained fairly homogeneous 131 through time and shows high-K dacitic composition (Sza-132 kács and Seghedi 1986; Vinkler et al. 1997). The geody-133 namic background of the CGH volcanism and particularly 134 the volcanic activity of southern Harghita and Ciomadul is 135 still hi...

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Abstract-The angrites are a small and heterogeneous group of achondritic meteorites with highly unusual chemical and mineralogical features. The abundant presence of glasses in D'Orbigny makes this rock a unique member of the angrite group. Glasses fill open spaces, form pockets, and occur as inclusions in olivines. Their physical settings exclude an incorporation from an external source. Major and trace element (rare earth elements [REE], Li, B, Be, transition elements, N and C) contents of these glasses and host olivines were measured combining laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), secondaryion mass spectrometry (SIMS), Nuclear Reaction Analysis (NRA), and EMP techniques. Based on the major element composition, glasses filling voids could represent either a melt formed by melting an angritic rock or a melt from which angrites could have crystallized. Trace element contents of these glasses strongly indicate a direct link to the D'Orbigny bulk meteorite. They are incompatible with the formation of the glasses by partial melting of a chondritic source rock or by shock melting. The refractory elements (e.g., Al, Ti, Ca) have about 10 ϫ CI abundances with CaO/TiO 2 and FeO/MnO ratios being approximately chondritic. Trace element abundances in the glasses appear to be governed by volatility and suggest that the refractory elements in the source had chondritic relative abundances. Although the glasses (and the whole rock) lack volatile elements such as Na and K, they are rich in some moderately volatile elements such as B, V, Mn, Fe (all with close to CI abundances), and Li (about 3-5 ϫ CI). These elements likely were added to the glass in a sub-solidus metasomatic elemental exchange event. We have identified a novel mechanism for alteration of glass and rock compositions based on an exchange of Al and Sc for Fe and other moderately volatile elements in addition to the well-known metasomatic exchange reactions (e.g., Ca-Na and Mg-Fe).Because glass inclusions in olivine were partly shielded from the metasomatic events by the host crystal, their chemical composition is believed to be closer to the original composition than that of any other glasses. The relative trace element abundances in glasses of glass inclusions in olivine and glass pockets are also unfractionated and at the 10 to 20 ϫ CI level. These glasses are chemically similar to the common void-filling glasses but show a much wider compositional variation. Inclusion glasses demonstrate that at least olivine grew with the help of a liquid. In analogy to olivines in carbonaceous chondrites, initial formation could also have been a vapor-liquid-solid condensation process. At that time, the glass had a purely refractory composition. This composition, however, was severely altered by the metasomatic addition of large amounts of FeO and other moderately volatile elements. The presence of volatile elements such as carbon and nitrogen in glasses of glass inclusions is another feature that appears to give these glasses a link with ...