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

Abstract

Late Pleistocene tephras derived by large explosive volcanic eruptions are widespread in the Mediterranean and surrounding areas. They are important isochronous markers in stratigraphic sections and therefore it is important to constrain their sources. We report here tephrochronology results using multiple criteria to characterize the volcanic products of the Late Pleistocene Ciomadul volcano in eastern-central Europe. This dacitic volcano had an explosive eruption stage between 57 and 30 ka. The specific petrological character (ash texture, occurrence of plagioclase and amphibole phenocrysts and their compositions), the high-K calc-alkaline major element composition and particularly the distinct trace element characteristics provide a strong fingerprint of the Ciomadul volcano. This can be used for correlating tephra and cryptotephra occurrences within this timeframe. Remarkably, during this period several volcanic eruptions produced tephras with similar glass major element composition. However, they differ from Ciomadul tephras by glass trace element abundances, ratios of strongly incompatible trace elements and their mineral cargo that serve as discrimination tools. We used (U-Th)/He zircon dates combined with U-Th in situ rim dates along with luminescence and radiocarbon dating to constrain the age of the explosive eruptions of Ciomadul that yielded distal tephra layers but lack of identified proximal deposits.

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“…The Ciomadul volcano is located at the SE extremity of the Călimani-Gurghiu-Harghita volcanic chain (NW–SE line). Its last eruption is very recent (57–30 ka 36 , 37 ) and geological and geophysical data together support that it is still active 3 , 7 . The volcanic chain has been active over the Neogene, with very last activity nowadays at the Ciomadul cone, while older volcanism (1.5 Ma) affected the Apuseni area 32 .…”

Crossing new frontiers: extending tephrochronology as a global geoscientific research tool

“…(1) Patton Seamount, North Pacific Ocean (Aoki, 2020) (2) Mount St. Helens, USA (Foo et al, 2020) (3) Azores archipelago (Wastegård et al, 2020) (4) Iceland (Meara et al, 2020) (5) Hekla volcano, Iceland (Larsen et al, 2020) (6) Loch Ashik, Scotland (Pyne-O'Donnell and Jensen, 2020) (7) Llyn Llech Owain, South Wales (8) Western Norway and Iceland (Saxby et al, 2020) (9) Eifel Volcanic Field, Germany (Förster et al, 2020) (10) Arma Veirana and Riparo Bombrini, Italy (Hirniak et al, 2020) (11) Central Mediterranean Sea (Insinga et al, 2020) (12) Ciomadul volcano, Eastern Carpathians, Romania (Harangi et al, 2020) -"Tephra Hunt in Transylvania" field conference venue (13) Lake Chala, Tanzania/Kenya (Martin-Jones et al, 2020) (14) Toba caldera, Sumatra (4+5)…”

“…The approach has been applied to some eruptive products of the dacitic Ciomadul lava dome complex in the Eastern Carpathians (Romania), the site of several significant Late Pleistocene eruptions with rather similar glass-shard chemical compositions (see Karátson et al, 2016). Harangi et al (2020) underline that the petrological characteristics such as ash texture, occurrence of plagioclase and amphibole phenocrysts and their composition, alongside major element composition, and particularly the distinct trace element characteristics provide strong fingerprints of eruptive products from Ciomadul volcano. These data can then be used for correlating tephra and cryptotephra occurrences.…”

“…Petrological and geochemical fingerprinting of volcanic products can provide valuable data for characterising the distinctive features of a volcanic eruption, and more securely pinpointing the source of distal tephras, and this is demonstrated by Harangi et al . (2020). The approach has been applied to some eruptive products of the dacitic Ciomadul lava dome complex in the Eastern Carpathians (Romania), the site of several significant Late Pleistocene eruptions with rather similar glass‐shard chemical compositions (see Karátson et al ., 2016).…”

“…Harangi et al . (2020) underline that the petrological characteristics such as ash texture, occurrence of plagioclase and amphibole phenocrysts and their composition, alongside major element composition, and particularly the distinct trace element characteristics provide strong fingerprints of eruptive products from Ciomadul volcano. These data can then be used for correlating tephra and cryptotephra occurrences.…”