Noble gas geochemistry of phenocrysts from the Ciomadul volcanic dome field (Eastern Carpathians)

Noble gas isotopic composition of fluid inclusions was analyzed in amphibole, plagioclase and clinopyroxene phenocrysts from the shoshonitic dacitic volcanic products Ciomadul dome field, youngest system within Carpathian-Pannonian Region. The highest Rc/RA ratios (3.0–3.8 RA) were obtained for high-mg Malnaş shoshonite. High-Al amphiboles Bixad pumices have between 1.16 2.11 RA. These values overlap with noble signature present-day CO2 emission. Thus, our new results reinforce conclusion that mantle component primitive magmas has relatively lower compared to nearby Perşani lithospheric mantle. This is likely due thorough metasomatic nature resulting elevated large ion lithophile elements high water content magmas. On other hand, plagioclase-hosted those low-Al are 0.06–0.12 RA 0.39–0.77 RA, respectively defining a dominant crustal origin (>90%) trapped fluids. Noteworthy, these minerals represent low-temperature crystal mush assemblage existed protracted time magma reservoir. We tested fraction contribution different end-member values, considering also effect aging on R/RA longer (up 50 kyr) residence time. resulted maximum ~50–60% high-Al amphibole-hosted lower, ~25% contribution, amphiboles. case can be explained by fresh recharge event shorter before eruption. this study imply inclusion amphibole could reflect magmatic end-member, which strongly metasomatized low values. heterogeneous even restricted area.