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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Clinopyroxene is a major constituent in most igneous rock types (hornblendite, diorite, containing phonolitic (tinguaite) magma. This study shows that antecryst recycling, also described for the first time in Ditrău, is a significant process during magma recharge and demonstrates that incorporated crystals can crucially affect the host magma composition and so whole-rock chemical data should be interpreted with great care.

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Camptonite dykes intrude the rift-related Mesozoic igneous body of the Ditrău 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 (An 4-34 ). A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT

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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.

13Synsedimentary and early diagenetic oxygen levels are estimated by evaluating celadonite-14 smectite formation in marine Jurassic black shale-hosted manganese-carbonates. Celadonite 15 formed under suboxic-dysaerobic conditions, Al-rich Fe-smectite formed at suboxic-anaerobic 16 conditions, and nontronite formed at anoxic-anaerobic conditions during sedimentary burial. A 17 genetic pathway by direct precipitation from solution is proposed for the enormous mass of 18 celadonite, based on mineral and textural evidence. Lamination of the manganese ore is 19 independent of clay-mineral composition and was given by a series of mineralized microbial Fe-20 rich biomats. 21