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Mogoșa, a Miocene composite volcano in the East Carpathians (NW Romania) generated by long-lived dome-building activity

Alexandru SZAKÁCS1 , Marinel KOVACS2

  • Affiliations: 1Institute of Geodynamics, Romanian Academy, Bucharest, Romania 2Technical University of Cluj-Napoca, North University Centre of Baia Mare, Baia Mare, Romania

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 117

  • Programme No: 3.15.22

  • Theme 3 > Session 15

Abstract

The Gutâi Volcanic Zone in north-western Romania is part of the Neogene volcanic arc of the fold-and-thrust belt of the Carpathian-Pannonian Region of Europe. It consists of a number of more or less eroded volcanic structures and unroofed shallow intrusions. Mogoșa is one of the most well-preserved volcanic edifices whose eruptive history and structure were unraveled by geological mapping and analytical investigations of a representative number of rock samples (radiometric dating, petrochemistry and mineral chemistry). Its volcanic products show a remarkably homogenous basaltic andesitic composition across an unusually long time-span of activity (1.8-2 My), erupted from a deep crustal (25-33 km near MOHO limit) magmatic plumbing system. The small-sized Mogoșa composite edifice (9 km across) is basically a compound volcanic dome system, built up of a number of successive dome-generating effusive events, interspersed with episodes of phreatomagmatic explosions and dome-collapse events generating volcaniclastic deposits at the lower slopes. A number of 4 dome-forming events have been readily recognized and mapped generating an edifice composed of a succession of partially or entirely overlapping extrusive domes. Actually, more domes were emplaced during the long-term volcanic evolution, since dome-collapse-related avalanche-type breccias were identified in the area called Giants Garden, whose original source was probably destroyed or completely buried by later effusive phases. Phreatomagmatic deposits identified at the edifice peripheries along with hydrothermal pipe breccias at even lower topographic exposure levels strongly suggests that the eruptive history of this volcano is more complex than just a succession of dome-generating eruptions constrained in a relatively small space.