The onset of the volcanism in the Ciomadul Volcanic Dome Complex (Eastern Carpathians): Eruption chronology and magma type variation

Abstract

a b s t r a c tThis article provides laser-ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and secondary ionization mass spectrometry (SIMS) U-Pb and U-Th zircon dates for crystals separated from Late Pleistocene dacitic lava dome rocks of the Ciomadul Volcanic Dome Complex (Eastern Carpathians, Romania). The analyses were performed on unpolished zircon prism faces (termed rim analyses) and on crystal interiors exposed through mechanical grinding an polishing (interior analyses). 206 Pb/ 238 U ages are corrected for Th-disequilibrium based on published and calculated distribution coefficients for U and Th using average whole-rock and individually analyzed zircon compositions. The

Noble Gas and Carbon Isotope Systematics at the Seemingly Inactive Ciomadul Volcano (Eastern‐Central Europe, Romania): Evidence for Volcanic Degassing

“…Volcanism at the Ciomadul volcanic dome field started around 1 Ma, while the most voluminous Ciomadul volcanic structure has developed over the last approximately 160 kyr (Molnár et al, , 2019. The second volcanic stage was characterized by initial lava dome effusion and then, after approximately 40 kyr of quiescence, a more explosive volcanic activity occurred (from 57 to 30 ka, Harangi et al, 2010;Karátson et al, 2016;Molnár et al, 2018Molnár et al, , 2019Moriya et al, 1995Moriya et al, , 1996Vinkler et al, 2007). The second volcanic stage was characterized by initial lava dome effusion and then, after approximately 40 kyr of quiescence, a more explosive volcanic activity occurred (from 57 to 30 ka, Harangi et al, 2010;Karátson et al, 2016;Molnár et al, 2018Molnár et al, , 2019Moriya et al, 1995Moriya et al, , 1996Vinkler et al, 2007).…”

“…Furthermore, the Ciomadul volcanic system is characterized by relatively high CO 2 gas fluxes . Molnár et al (2018Molnár et al ( , 2019 presented a detailed eruption chronology for the Ciomadul lava dome field involving the Ciomadul volcanic complex and emphasized that volcanic activity could be renewed even after long (>100 kyr) repose times. The measurements of U-Th and U-Pb spot ages on zircons suggest a long-standing magma storage that could go back as far as about 350 ka Lukács et al, 2018).…”

Fingerprinting the Late Pleistocene tephras of Ciomadul volcano, eastern–central Europe

“…U‐Th isotope spot analyses of single zircon crystals (SM_Table 8) were conducted for disequilibrium correction calculations of the F T ‐corrected (U‐Th)/He dates. Both average crystallization ages and individual ages from the double‐dating method were applied for the correction (see details in Danišík et al , and Molnár et al , , ). For TGS tephra, the ‘average crystallization age’ correction method yielded an eruption age of 33.4 ± 4.2 ka ( n = 13; goodness of fit: 0.003; average zircon crystallization age: 157 ± 10 ka), whereas the ‘double‐dating’ method gave 29.5 ± 1.6 ka ( n = 5; goodness of fit: 0.753; SM_Table 7, Fig.…”

“…The volcanic rocks of the Ciomadul volcanic dome field have characteristic major element compositions with relatively high‐K abundances compared to the older calc‐alkaline volcanic products of the nearby South Harghita volcanic chain (Fig. ; Szakács and Seghedi, ; Seghedi et al , ; Szakács et al , ; Vinkler et al , ; Molnár et al , ). The glasses share the bimodal compositional character with bulk rocks (SM_Tables 1 and 2; Fig.…”

“…They are located in central and southern Italy, Greece and Anatolia, whereas an additional potential volcanic source was only recently recognized in the southeastern Carpathians, Romania, i.e. the late Pleistocene Ciomadul volcano (Harangi et al , ; Szakács et al , ; Karátson et al , ; Molnár et al , , ). Tephra beds in the Black Sea drilling cores (Cullen et al , ), in loess deposits of Ukraine (Wulf et al , ) and in Middle Palaeolithic caves (Veres et al , ) have been recently suggested as derived from large explosive eruption events of Ciomadul volcano.…”