{{Short description|Volcano in Romania}} {{good article}} {{Infobox mountain |name=Ciomadul |other_name=Csomád ([[Hungarian language|hu]]) |image=Lacul Sfanta Ana - Relief.jpg |image_caption=3D model of Ciomadul's central sector seen from the south |map=Romania |location=[[Romania]], [[Harghita County]] |coordinates = {{coord|46.13|N|25.88|E|type:mountain_scale:100000|format=dms|display=inline,title}} |coordinates_ref=<ref name="GVP" /> |elevation_m=1289 |elevation_ref=<ref name="GVP" /> |range=[[Carpathian Mountains]] |type=[[Lava dome]]s |age=[[Pleistocene]] |volcanic_belt=Carpathian volcanic arc |last_eruption= }} '''Ciomadul''' ({{langx|hu|Csomád}}) is a [[dormant volcano]] in [[Romania]].{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=43}} It is in the [[Eastern Carpathians]], between the spa towns of [[Băile Tușnad]] and [[Balvanyos]]. Ciomadul lies at the southeastern end of the Carpathian volcanic chain and it is the youngest volcano of the Carpatho-Pannonian region. Ciomadul consists of several [[lava dome]]s with two embedded [[Volcanic crater|explosion craters]] known as Mohoș and Sfânta Ana, the latter of which contains a [[Volcanic crater lake|crater lake]], [[Lake Sfânta Ana]]. The dominant volcanic rock at Ciomadul is [[potassium]]-rich [[dacite]].
Volcanic activity at Ciomadul commenced with [[Effusive eruption|effusive activity]] about one million years ago. Most of the volcano was constructed between 650,000 – 500,000 years ago.
Between 56,000 and 32,000 years ago [[Explosive eruption|explosive volcanic activity]] occurred at Ciomadul. Both the exact dates of the various eruptions and of the formation of the Sfânta Ana and Mohoș craters are unclear, partly because dates obtained by [[potassium-argon dating]] and other dating techniques deviate from each other. Some eruptions may have reached sub-[[Plinian eruption|Plinian]] strength, ejecting [[volcanic ash]] as far as the [[Black Sea]].
The last eruption took place between 32,600 and 27,500 years ago. Its date is likewise unclear. Ongoing seismic and [[Geothermal gradient|geothermal activity]], and exhalations of [[volcanic gas]] and evidence of a still existing [[magma chamber]] indicate that Ciomadul is a [[potentially active volcano]].
== Geography and geology == === Regional setting ===
With the exception of [[Greece]] and [[Italy]], the most recent [[volcanism|volcanic activity]] in Continental Europe occurred between 40,000 and 6,500 years ago in [[Garrotxa]], the [[Massif Central]] and the [[Vulkaneifel]].{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|pp=66–67}}
Volcanism in the region of [[Carpathian Mountains|Carpathia]] and [[Pannonia]] has been ongoing since 20 million years ago but has decreased during the [[Quaternary]]. No eruptions took place in the [[Holocene]].{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1498}} The last volcanism occurred at Ciomadul in the last glacial age.{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=43}} Sparse [[basaltic]] volcanism has also taken place in the area, forming [[monogenetic volcanic field]]s.{{sfn|Harangi|Sági|Seghedi|Ntaflos|2013|p=44}}
A {{convert|700|km|mi|adj=mid|-long}} [[volcanic arc]] lies in the [[Carpathians]]. In its southern segment, also known as the Călimani (Kelemen) – Gurghiu (Görgényi) – Harghita (Hargita) chain,{{sfn|Kis|Ionescu|Cardellini|Harangi|2017|p=120}}{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=44}}{{sfn|Molnár|Harangi|Lukács|Dunkl|2018|p=3}} volcanism has migrated between 9 and 0.22 million years ago southward, forming a {{circa}} {{convert|100|km|mi|adj=mid|-long}} volcanic chain.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}} Magma output progressively decreased during time, with early volcanoes being large [[stratovolcano]]es sometimes featuring [[caldera]]-forming eruptions, while more recent activity includes [[monogenetic volcanic field|monogenetic]] volcanoes{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=2}}{{sfn|Karátson|Wulf|Vereș|Magyari|2016|p=30}} although more precise dating and volume estimation efforts at Ciomad have found an increase of eruption rates over time.{{sfn|Karátson|Telbisz|Dibacto|Lahitte|2019|p=12}}
This volcanism occurs in a setting where the collision between the [[Eurasian Plate]] and the Tisza-Dacia [[microplate]] took place,{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=3}}{{sfn|Kis|Ionescu|Cardellini|Harangi|2017|p=121}} preceded by a stage of [[subduction]] involving a narrow [[ocean]].{{sfn|Karátson|Telbisz|Dibacto|Lahitte|2019|p=2}} This is part of the collision between the [[African Plate]] and the Eurasian Plate; [[subduction]] may still be underway in the area of the Carpathians.{{sfn|Mitrofan|2000|p=1447}} The {{ill|Vrancea Zone|bg|Зона Вранча|ru|Зона Вранча|uk|Зона Вранча}}, which is {{convert|50|km}} away from Ciomadul, features ongoing [[earthquake]] activity; deep earthquakes suggest that a remnant of a [[slab (geology)|slab]] exists beneath the Vrancea Zone.{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=67}} This [[tectonic setting]] may also be responsible for ongoing exhumation in the southeastern Carpathians,{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=33}} volcanism at Ciomadul and the [[Perșani volcanic field]],{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=69}} {{convert|40|km}} south of Ciomad,{{sfn|Harangi|Sági|Seghedi|Ntaflos|2013|p=48}} which was concurrently active to the older Ciomadul activity.{{sfn|Molnár|Lukács|Dunkl|Schmitt|2019|p=135}} Other theories on Ciomadul's volcanic activity imply [[delamination]] of the [[lithosphere]] or [[Oceanic trench#Trench rollback|roll-back]] of the subduction zone.{{sfn|Kiss|Harangi|Ntaflos|Mason|2014|p=2}}
Volcanism in this chain is [[calc-alkaline]], yielding both [[andesite]], [[dacite]],{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}} and [[rhyolite]].{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=44}} Three million years ago, a change in the chemistry of volcanism occurred, with an increased content of [[potassium]] in the rocks. This change in composition geographically coincided with the volcanic activity crossing a [[lineament]] known as the Trotuș line.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}}{{sfn|Kiss|Harangi|Ntaflos|Mason|2014|p=2}}{{sfn|Molnár|Harangi|Lukács|Dunkl|2018|p=3}}
=== Volcano === [[File:Lacul Sfanta Ana - Panoramic.gif|thumb|3D model of the volcano]]
Ciomadul is located in the southeastern [[Carpathians]],{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1498}} at the end of the Călimani (Kelemen) – Gurghiu (Görgényi) – Harghita (Hargita) volcanic chain,{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}} and is also known as Csomád in Hungarian.{{sfn|Diaconu|Tanțău|Knorr|Borken|2019|p=2}} The [[gorge]] of the [[Olt River]] separates Ciomadul from the Harghita Mountains.{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=45}} The towns of [[Băile Tușnad]] and [[Bixad, Covasna|Bixad]] are close to the volcano,{{sfn|Harangi|Novák|Kiss|Seghedi|2015|p=85}} and a road leads up the volcano from the southeast and goes past the Mohoș swamp to [[Lake Sfânta Ana]].{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1499}}{{sfn|Diaconu|Tanțău|Knorr|Borken|2019|p=3}} The basement of the volcano is formed by [[flysch]] of [[Cretaceous]] age{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=3}}{{sfn|Kis|Ionescu|Cardellini|Harangi|2017|p=121}} and by older volcanics; in some places volcanic rocks overlie fluvial deposits.{{sfn|Karátson|Telbisz|Dibacto|Lahitte|2019|p=3}}
Places around Ciomadul were first mentioned in 1349;{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=5}} the Saxon mineralogist Johann Ehrenwert Fichtel was the first to interpret it as a volcano, in 1780.{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=vi}} The idea that Ciomadul could be a still active volcano was first proposed in the same year on the basis of its young appearance and the release of gas.{{sfn|Karátson|Wulf|Vereș|Magyari|2016|p=32}} These discoveries drew scholars and visitors to the volcano{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=vi}} and the first scientific analysis of the volcano was published just eight years later.{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=9}} While a publication in 1964 postulated that the [[tuff]]s of Ciomadul were reworked [[Pliocene]] [[volcanite]]s, the late [[Pleistocene]] age was established soon afterwards.{{sfn|Karátson|Wulf|Vereș|Magyari|2016|p=32}} The volcano is the youngest volcanic centre in the Carpathians{{sfn|Besutiu|Szakács|Zlagnean|Isac|2021|p=1}} and has a more rugged appearance than the surrounding mountains.{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=40}}
Ciomadul is formed by a complex of [[lava dome]]s and other volcanic material that form a south-tilting ridge that rises above the {{convert|700|m|ft|adj=mid|-high}} surrounding Lower Ciuk Basin. Individual lava domes form cone-shaped hills,{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=45}} which reach heights of {{convert|300|-|400|m}} and widths of {{convert|1|-|2|km}}. Individual domes include Haramul Ierbos (Fű-Haram in Hungarian), Haramul Mare (Nagy-Haram), Haramul Mic (Kis-Haram), Vf. Cetății (Vár-tető), Vf. Comloș (Komlós-tető), Vf. Surduc (Szurdok-tető){{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=46}} and Dealul Mare southeast from the main complex.{{sfn|Karátson|Telbisz|Dibacto|Lahitte|2019|p=4}} The central cluster of domes is elliptical{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=3}} and tectonic [[fault (geology)|faults]] influenced their growth.{{sfn|Lahitte|Dibacto|Karátson|Gertisser|2019|p=11}} The highest point of the complex is Ciomadul Mare (Nagy-Csomád) with an altitude of {{convert|1301|m}}.{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=45}} Some domes were later affected by [[erosion]], [[Explosive eruption|explosive]] activity{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=5}} or [[fumarole|fumarolic alteration]].{{sfn|Kis|Ionescu|Cardellini|Harangi|2017|p=121}} The whole volcanic complex covers a surface area of {{convert|80|km2}},{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=3}} and is surrounded by a circular/semicircular plain made of volcanic debris.{{sfn|Magyari|Vereș|Wennrich|Wagner|2014|p=281}}
[[File:Szent Anna tó 3.jpg|thumb|Sfânta Ana crater and lake]] The lava dome complex contains two [[Volcanic crater|crater]]s, named Mohoș and Sfânta Ana. They were formed in the previously existing lava domes{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}}{{sfn|Harangi|Novák|Kiss|Seghedi|2015|p=83}} which form the western margin of the craters, while products of [[explosive eruption]]s crop out in the east.{{sfn|Molnár|Lukács|Dunkl|Schmitt|2019|p=135}} The Sfânta Ana crater is {{circa}} {{convert|1600|m}} wide and {{circa}} {{convert|200|m}} deep beneath the rim, comparable with the crater of [[El Chichón]] volcano in [[Mexico]].{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=46}} This crater lacks a breach and is relatively unaffected by erosion.{{sfn|Karátson|Thouret|Moriya|Lomoschitz|1999|p=178}} It contains a {{convert|6|m|ft|adj=mid|-deep}} [[Volcanic crater lake|crater lake]],{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}} which once may have been over {{convert|12|m}} deep. This {{circa}} {{convert|189.9|km2|mi2|adj=mid}} lake is known as Lake Sfânta Ana ({{coord|46|07|35|N|25|53|17|E}}) and lies at an altitude of {{convert|946|m}};{{sfn|Magyari|Vereș|Wennrich|Wagner|2014|p=281}}{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=50}} its ecosystem and environment has drawn the attention of scientists for two centuries.{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=vi}}
The Mohoș crater lies at an altitude of {{convert|1050|m}}.{{sfn|Tanțău|Reille|Beaulieu|Fărcaș|2003|p=113}} It is larger than Sfânta Ana with a diameter of {{convert|1.9|km}} and not as deep{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=6}} with its bottom lying above sea level. It is filled with a {{convert|10|m|ft|adj=mid|-thick}} and {{convert|80|ha|m2|adj=mid|order=flip}} ''[[Sphagnum]]'' [[peat bog]] and its rim is cut by the Sfânta Ana crater.{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=46}}{{sfn|Tanțău|Reille|Beaulieu|Fărcaș|2003|pp=113–114}} [[File:Mohos Peat Bog 1.jpg|thumb|Peat bog in Mohoș crater]] Unlike Sfânta Ana, the Mohoș crater has been breached by erosion, causing the formation of an outlet valley.{{sfn|Karátson|Thouret|Moriya|Lomoschitz|1999|p=181}} Both craters were formed by [[explosive eruption]]s and distinguishing between the deposits of both is difficult.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}} The existence of an even larger crater with a diameter of {{convert|2|-|2.5|km}} has been suggested,{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=53}} encompassing both Sfânta Ana and Mohoș.{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=54}}
[[Pyroclastic flow]] deposits generated by Ciomadul have been found on its northeastern, southern and western slopes.{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=46}} They reach a distance of as much as {{convert|25|km}} from the volcano.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}} At Tușnad road, one of the flows has a thickness of {{circa}} {{convert|10|m}}.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1501}} Tephra fall bed,{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}} [[lapilli]],{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1501}} and surge deposits are also found, and the flow deposits contain pumice blocks.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}} One lapilli layer, {{convert|20|-|23|cm}} thick, from Ciomadul has been identified {{convert|40|km}} east of the volcano.{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=8}} The whole pyroclastic formation has been subdivided into three classes known as "Early Phreatomagmatic + Plinian Activity", "Middle Plinian Activity" and "Latest Sfânta Ana Phreatomagmatic Activity". Each comprise a number of individual tephra layers{{sfn|Karátson|Wulf|Vereș|Magyari|2016|p=44}} that were erupted 42,000—40,000, around 31,500 and 29,000—28,000 years ago.{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=99}} Some of these eruptions may have dammed the Olt river; when the river returned on its course it produced [[lahar]] deposits.{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=110}}
Other [[landform]]s at Ciomadul include [[Lava coulee|coulees]] and [[lava flow]]s.{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=3}} The total volume of the complex is about {{convert|8|-|15|km3}} [[dense rock equivalent]].{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=67}} Drilling has identified the existence of an [[intrusion]] at a depth of {{convert|575|m}}.{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=3}} Finally, volcanic erosion products and tephra occur all over the volcanic complex{{sfn|Karátson|Telbisz|Dibacto|Lahitte|2019|p=6}} and up to {{convert|350|km}} east of it.{{sfn|Lahitte|Dibacto|Karátson|Gertisser|2019|p=2}}
Older volcanic centres extend northwest of Ciomadul. With increasing distance they are the 2.5—1.5 million-year-old Pilisca centre, the 2.8—2.2 million-year-old Cucu centre and the 4.3—3.6 million-year-old Luci-Lazu and Șumuleu-Ciuc volcanic centres. South of Ciomadul the Murgul [[shoshonite]]s were erupted 2.3—1.5 million years ago;{{sfn|Harangi|Novák|Kiss|Seghedi|2015|p=84}}{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=68}} they represent [[cryptodome]]s.{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=67}} [[Andesite]] lava flows from Pilisca underlie the Ciomadul deposits in some places.{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=7}}
=== Composition ===
The principal rock is [[dacite]], which defines a [[potassium]]-rich [[calc-alkaline]] suite.{{sfn|Molnár|Czuppon|Palcsu|Benkó|2021|p=3}} The rocks have a [[Porphyritic|porphyric]] appearance and contain few vesicles. They are also very rich in crystals,{{sfn|Molnár|Harangi|Lukács|Dunkl|2018|p=4}}{{sfn|Karátson|Wulf|Vereș|Magyari|2016|p=30}}{{sfn|Kiss|Harangi|Ntaflos|Mason|2014|p=4}} with the dominant [[phenocryst]]-forming minerals being [[biotite]], [[hornblende]] and [[plagioclase]]. Less important are [[allanite]], [[apatite]], [[clinopyroxene]], [[olivine]], [[orthopyroxene]], [[quartz]], [[sphene]] and [[zircon]].{{sfn|Karátson|Wulf|Vereș|Magyari|2016|p=30}}{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=45}} The [[groundmass]] contains [[plagioclase]], [[pyroxene]], [[silicon dioxide]] and [[oxides]] of [[iron]] and [[titanium]].{{sfn|Kiss|Harangi|Ntaflos|Mason|2014|p=4}} Clots formed by various [[felsic]] crystals are common.{{sfn|Cserép|Szemerédi|Harangi|Erdmann|2023|p=4}} The composition of Ciomadul's rocks has been fairly constant throughout its evolution{{sfn|Harangi|Novák|Kiss|Seghedi|2015|p=83}} albeit with two shifts 1 million and 650,000 years before present,{{sfn|Molnár|Harangi|Lukács|Dunkl|2018|p=14}} and this diversity of its components indicate that the genesis of Ciomadul magmas involved mixing between [[felsic]] and [[mafic]] magma.{{sfn|Harangi|Novák|Kiss|Seghedi|2015|p=85}} The phenocryst compositions at Ciomadul are unlike these at other volcanoes in the Carpathians.{{sfn|Lukács|Caricchi|Schmitt|Bachmann|2021|p=2}} The magmas derive from the [[upper mantle (Earth)|upper mantle]] [[lithosphere]], which underwent [[metasomatism|metasomatic]] alteration.{{sfn|Molnár|Czuppon|Palcsu|Benkó|2021|p=2}}
Compositionally, the tephras of Ciomadul have been subdivided into two groups, one called Tușnad‐type and the other Bixad‐type.{{sfn|Harangi|Molnár|Schmitt|Dunkl|2020|p=233}} A large proportion of crystals in the rocks consists of [[antecryst]]s and [[xenocryst]]s, making [[radiometric dating]] of the rocks difficult. These include [[amphibole]], [[biotite]], [[feldspar]] and [[zircon]].{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}} The zircons formed almost continuously over hundred thousands of years within Ciomadul's magma chamber, indicating a steady crystallization of the chamber.{{sfn|Lukács|Caricchi|Schmitt|Bachmann|2021|p=6}} Differences in magma temperature, crystal content and the participation of pre-existent crystal mushes determine whether an eruption will be effusive or explosive.{{sfn|Cserép|Szemerédi|Harangi|Erdmann|2023|p=22}}
The temperature of the [[magma chamber]] has been estimated to be about {{convert|700|-|750|C}}, with heating of over {{convert|200|C-change}} occurring before some eruptions according to thermometry calculation. Volcanic activity was most likely triggered by the injection of [[basaltic]] magma into the [[felsic]] magma chamber before the actual eruption,{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=76}}{{sfn|Kiss|Harangi|Ntaflos|Mason|2014|p=24}} as has been observed at other silicic volcanoes around the world,{{sfn|Lahitte|Dibacto|Karátson|Gertisser|2019|p=3}} but the magma chamber probably kept being recharged even between eruptions.{{sfn|Lukács|Caricchi|Schmitt|Bachmann|2021|p=7}} The [[amphibole]]s in the rocks formed at depths of {{convert|7|-|14|km}}.{{sfn|Harangi|Novák|Kiss|Seghedi|2015|p=87}} The magma output of Ciomadul is about {{convert|0.009|km3/kyr|mi3/kyr}}{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=15}} while magma chamber recharge may have reached {{convert|0.00013|km3/yr|mi3/yr}}.{{sfn|Lukács|Caricchi|Schmitt|Bachmann|2021|p=9}}
== Eruptive history ==
Ciomadul has been active for over half a million years,{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1498}} with the oldest activity between 1,000,000 and 750,000 years ago forming [[lava dome]]s.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}}{{sfn|Molnár|Harangi|Lukács|Dunkl|2018|p=14}} Older estimates indicate that activity did not start before 250,000 years ago, while more recent research indicated a start of volcanism over 600,000/{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=69}}{{sfn|Harangi|Novák|Kiss|Seghedi|2015|p=83}} 850,000 years ago.{{sfn|Karátson|Telbisz|Dibacto|Lahitte|2019|p=4}} Volcanism at Ciomadul consisted mostly of the extrusion of lava domes, their collapse forming block-and-ash flows and [[Plinian eruption|subplinian]] and [[Vulcanian eruption|Vulcanian]] eruptions{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=69}} separated by long periods of rest.{{sfn|Laumonier|Karakas|Bachmann|Gaillard|2019|p=79}} The volcanic history of Ciomadul has been subdivided into an effusive phase that lasted until about 440,000 years ago and an explosive phase that began 200,000 years ago{{sfn|Karátson|Telbisz|Dibacto|Lahitte|2019|p=2}} during which magma output increased 30-fold{{sfn|Karátson|Telbisz|Dibacto|Lahitte|2019|p=15}} and which is known as "young Ciomad".{{sfn|Molnár|Lukács|Dunkl|Schmitt|2019|p=134}} An alternative description envisages an "old Ciomadul" between 1,000,000 — 300,000 years ago and a "young Ciomad eruptive period" between 160,000 — 30,000 years ago, with the latter in turn subdivided into five stages that emplaced about {{convert|7|km3}} of rock.{{sfn|Lukács|Caricchi|Schmitt|Bachmann|2021|p=2}}{{sfn|Molnár|Czuppon|Palcsu|Benkó|2021|p=2}}
A gap of about 500,000 years separates Ciomadul from the activity of other volcanoes in the area.{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=14}} The two oldest dates of 1,020,000 and 850,000 years ago were obtained on peripheral lava domes.{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=49}} Early activity between {{circa}} 850,000 — 440,000 years ago built the southeastern domes.{{sfn|Lahitte|Dibacto|Karátson|Gertisser|2019|p=11}} This [[effusive]] phase is also known as "old Ciomad",{{sfn|Kiss|Harangi|Ntaflos|Mason|2014|p=2}} and eruptions were separated by long pauses without volcanic activity from each other.{{sfn|Molnár|Harangi|Lukács|Dunkl|2018|p=12}} The dates obtained by [[potassium-argon dating]] are much older;{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=74}} there is substantial disagreement between dates obtained by [[potassium-argon dating]] or [[Argon–argon dating|argon-argon dating]] on the one hand and [[uranium-thorium dating]] on the other hand at Ciomadul.{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=75}}{{sfn|Molnár|Harangi|Lukács|Dunkl|2018|p=12}} These dates indicate that the formation of the central lava domes took place between 590,000 and 140,000 years ago.{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=12}}
Around 200,000 — 130,000{{sfn|Lahitte|Dibacto|Karátson|Gertisser|2019|p=22}} or 150,000 — 100,000 years ago a number of lava domes developed.{{sfn|Molnár|Lukács|Dunkl|Schmitt|2019|p=139}} [[Explosive eruption]]s became common only about 57,000 years ago.{{sfn|Harangi|Molnár|Schmitt|Dunkl|2020|p=233}} Between 56,000 and 32,000 years ago, explosive activity occurred at Ciomadul. That timespan coincides with the deposition of [[tephra]] from volcanoes in Italy in Europe; it is possible that tephra also came from Ciomadul.{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=67}} Indeed, the age of Ciomadul's last eruption overlaps with the age of the [[Campanian Ignimbrite eruption|Campanian Ignimbrite]].{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=76}}
=== Tephras ===
Ciomad has produced far-flung [[tephra]]s, which reached as far as [[Ukraine]]{{sfn|Besutiu|Szakács|Zlagnean|Isac|2021|p=2}} and have been recovered from the Ursului Cave of the [[Perșani Mountains]].<ref name="VeresCosac2017" /> Some tephra layers found in two drilling cores of the [[Black Sea]] may have originated at Ciomad<ref name="WulfFedorowicz2016" /> but reliably distinguishing between Ciomadul tephras and these from [[Nisyros]] and [[Anatolia]]n volcanoes is difficult.{{sfn|Harangi|Molnár|Schmitt|Dunkl|2020|p=241}}
The Roxolany Tephra has been found as far as [[Odesa]], [[Ukraine]], {{convert|350|km}} away from Ciomadul.<ref name="KaratsonWulf2016" /> If the Roxolany Tephra was formed by the youngest eruption of Ciomadul, the youngest eruption would have occurred 29,600 [[Radiocarbon dating#Calibration|calibrated radiocarbon]] years ago based on independent dates of the tephra.<ref name="WulfFedorowicz2016" /> From the other point of view, the clinopyroxene‐bearing Roxolany tephra was unlikely to be derived from Ciomadul, as it differs significantly from Ciomadul typical phenocryst assemblage containing amphibole.{{sfn|Harangi|Molnár|Schmitt|Dunkl|2020|p=241}} Based on new chronostratigraphic model for the Roxolany section, supported by updated magnetostratigraphic results and compiled existing radiocarbon and [[optically stimulated luminescence]] dates, the Roxolany tephra was deposited around 143,800 years ago.<ref name="HlavatskyiBakhmutov2020" />
=== Recent explosive activity ===
Explosive activity may have occurred in two separate episodes, one 57,000/56,000–44,000 years ago and the other 34,000/33,000–29,000 years ago.{{sfn|Cserép|Szemerédi|Harangi|Erdmann|2023|p=4}}{{sfn|Harangi|Molnár|Schmitt|Dunkl|2020|p=239}} An earlier explosive eruption about 55,900 ± 2,300 years ago may be the origin of the Mohoș crater,{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=75}} with another proposed [[potassium-argon dating|potassium-argon date]] being {{circa}} 220,000 years ago. Mohoș crater is probably older than the Sfânta Ana crater.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1505}} A [[phreatomagmatic]] deposit northeast of Mohoș was formed by an eruption of the Mohoș crater;{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=8}} this eruption may be the source of the "Turia type" phreatomagmatic deposits,<ref name="KaratsonWulf2016" /> which are dated to have occurred about 51,000 ± 4,800 years ago.{{sfn|Karátson|Wulf|Vereș|Magyari|2016|p=46}} In one view, a volcanically quiet period followed an effusive eruption 48,000{{sfn|Cserép|Szemerédi|Harangi|Erdmann|2023|p=4}} or 42,900 years ago named "Piscul Pietros" and lasted until 31,510 years ago,{{sfn|Karátson|Wulf|Vereș|Magyari|2016|p=47}} when a Plinian eruption occurred. This latter eruption deposited {{convert|0.6|m|ft|adj=mid|-thick}} ash as far as {{convert|21|km}} from the vent at one site.{{sfn|Karátson|Wulf|Vereș|Magyari|2016|p=49}} Alternatively, 38,900 ± 1,700 years ago a subplinian eruption occurred at Ciomadul; it may have formed the Sfânta Ana crater.{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=74}} This date would correspond to that of the so-called "MK-202" tephra.<ref name="DanisikSchmitt" /> Piscul Pietros has been also dated to be 48,000 ± 6,000{{sfn|Molnár|Lukács|Dunkl|Schmitt|2019|p=139}} or 60,000 ± 5,000 years old.{{sfn|Karátson|Telbisz|Dibacto|Lahitte|2019|p=5}}
The age of the last eruption is controversial{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1498}} but probably took place about 30,000 years ago.{{sfn|Molnár|Czuppon|Palcsu|Benkó|2021|p=2}} In 1994, [[radiocarbon]] dating yielded an age of 10,700 ± 800 years [[before present|Before Present]] from a [[pyroclastic flow]]. Later, paleosoils and other samples from the same flow were used to deduce similar ages of over 36,770, 42,650, over 35,670 and over 35,520 years before present, respectively.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1499}} Thus this youngest age estimate was discarded.{{sfn|Karátson|Wulf|Vereș|Magyari|2016|p=33}} In 2010, further research identified two younger eruptions, one occurring 39,000 years Before Present and the other 27,500 years Before Present.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1500}} Other data obtained by [[uranium-thorium dating]] indicate an age of 32,600 ± 1,000 years ago for the youngest eruption.{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=74}} Both of these eruptions took place at Sfânta Ana and imply a repose period between eruptions of over 10,000 years.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1505}} Much older dates obtained by [[potassium-argon dating]] are not considered reliable.{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=49}} Alternatively, the latest eruption may have occurred at a [[Parasitic cone|satellite vent]] seeing as sedimentation of Lake Sfânta Ana has been ongoing since 26,000 years ago.{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=53}} These two recent eruptions were fed by different magmas, with the younger eruption coming from deeper [[magma chamber]]s ({{convert|5|-|12|km}} versus {{convert|4|km}}) and involving more primitive magma.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1504}}
After the last eruption, the lava domes were subject to glacial [[weathering]], such as [[frost shattering]] that produced [[stone run]]s.{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=44}} An 1838 document by an unknown author stated that even old legends do not record eruptive activity at Ciomadul,{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|pp=7-8}} and there is no evidence in Lake Sfânta Ana sediments of [[tephra]] layers that might indicate more recent eruptions.{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=52}}
== Current status == Presently, Ciomadul displays seismic activity,{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=45}} release of [[carbon dioxide]] from bubbling pools and bogs and [[mofetta]]s{{sfn|Molnár|Czuppon|Palcsu|Benkó|2021|p=2}} and anomalous [[heat flow]]{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=45}} reaching {{convert|85|-|120|W/m2}}.{{sfn|Harangi|Novák|Kiss|Seghedi|2015|p=83}} Outgassing of [[carbon dioxide]], [[hydrogen sulfide]] and mostly [[abiotic]] [[methane]] have been found at Ciomadul,<ref name="KisIonescu2016" /> forming [[sulfide]] deposits in some caverns.{{sfn|Sarbu|Aerts|Flot|Van Spanning|2018|p=175}} The total output of [[carbon dioxide]] exceeds about {{convert|8700|t}}{{sfn|Kis|Ionescu|Cardellini|Harangi|2017|p=125}} per year, while the output of [[methane]] amounts to {{convert|1.3|t}} per year.<ref name="KisIonescu2016" /> Carbon dioxide concentrations in some places such as caverns can be high enough to become dangerous to people and animals, and is reflected in place names - such as Peștera Ucigașă (Gyilkos-barlang) which mean "killer cave"{{sfn|Kis|Ionescu|Cardellini|Harangi|2017|p=121}} while Puturosu means "stinky" - {{sfn|Karátson|Telbisz|Dibacto|Lahitte|2019|p=5}} and local legends of a "gate to hell".{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=20}} Former [[alum]] and [[sulfur]] [[mining|mines]] east of Ciomadul were abandoned due to the dangers from toxic gases.{{sfn|Sarbu|Aerts|Flot|Van Spanning|2018|p=174}} The carbon dioxide is accompanied by [[noble gas]]es derived from the [[mantle (geology)|mantle]].{{sfn|Molnár|Czuppon|Palcsu|Benkó|2021|p=2}} The gases may come directly from the mantle, rather than from magma.{{sfn|Szakács|Kovács|2023|p=4}}
At depths of {{convert|5|to|27|km}} and especially {{convert|9|to|21|km}},{{sfn|Laumonier|Karakas|Bachmann|Gaillard|2019|p=80}} a [[magma chamber]] has been identified beneath Ciomadul,{{sfn|Harangi|Novák|Kiss|Seghedi|2015|p=83}}{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=46}} based on [[magnetotelluric]] data,{{sfn|Harangi|Novák|Kiss|Seghedi|2015|p=93}} and several {{convert|10|km3}} of magma may still be stored underneath Ciomadul.<ref name="Laumonier2018" /> An alternative explanation is that there are less than a few cubic kilometres of magma.{{sfn|Szakács|Kovács|2023|p=3.}} This magmatic reservoir appears to have about 5–15% of melt by volume fraction,{{sfn|Cserép|Szemerédi|Harangi|Erdmann|2023|p=4}} with a vertical stratification by temperature.{{sfn|Laumonier|Karakas|Bachmann|Gaillard|2019|p=88}} A deeper [[basaltic]] melt zone may also exist<ref name="NovákHarangi2012" /> at a depth of around {{convert|30|km}}.{{sfn|Laumonier|Karakas|Bachmann|Gaillard|2019|p=86}} Further, a zone of low seismic velocity has been identified with geophysical and seismic modelling in the lower crust and upper mantle beneath Ciomad, down to depths of {{Convert|110|km}} or {{Convert|400|km}}.{{sfn|Harangi|Sági|Seghedi|Ntaflos|2013|p=48}}
[[Hydrothermal]] activity has been noted at Ciomadul and Tușnad-Băi, including a high temperature system at depth with temperatures exceeding {{convert|225|C}}.{{sfn|Mitrofan|2000|p=1447}} The Tușnad-Băi springs have temperatures of {{convert|15|-|23|C}} and discharge salty, [[carbon dioxide]]-rich water which emerges from [[Pyroclastic rock|pyroclastic]] deposits.{{sfn|Mitrofan|2000|p=1448}} They are used in [[spa]]s in the area.{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=141}} In one cave, [[Autotroph|autotropic]] bacterial [[biofilm]]s have been found which subsist on the exhaled gases or the sulfur deposits.{{sfn|Sarbu|Aerts|Flot|Van Spanning|2018|pp=183–184}}
== Future activity ==
Volcanoes are usually considered to be active if they have had eruptions during the [[Holocene]]. However, as demonstrated by the unexpected eruption of [[Chaitén (volcano)|Chaiten]] volcano in [[Chile]] in May 2008, even long-inactive volcanoes can become active again. Such volcanoes can constitute a threat to regions with seemingly quiet volcanism.{{sfn|Harangi|Molnár|Vinkler|Kiss|2010|p=1498}} Ciomadul has had repose periods that lasted longer than the timespan elapsed since the last eruption.{{sfn|Cserép|Szemerédi|Harangi|Erdmann|2023|p=4}} [[Zircon]] crystallization data imply that the magma chambers of Ciomadul were active over time spans of over 300,000 years.{{sfn|Harangi|Lukács|Schmitt|Dunkl|2015|p=76}}
Uniquely, Ciomadul is a still alive volcano in Eastern Europe and its craters have a youthful appearance.{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=46}} There is always the possibility of renewed volcanic activity if the magma chamber has not solidified{{sfn|Harangi|Novák|Kiss|Seghedi|2015|pp=82–83}} even if there is no positive evidence of ongoing magma generation.{{sfn|Besutiu|Szakács|Zlagnean|Isac|2021|p=3}} Deep earthquake activity at Ciomadul occurs down to a depth of {{convert|70|km}}, indicating that the volcanic system between the magma chamber and lithospheric melts is still active.{{sfn|Szakács|Seghedi|Pécskay|Mirea|2015|p=16}} It is considered to be a potentially active volcano{{sfn|Kiss|Harangi|Ntaflos|Mason|2014|p=2}} although the risk of impending eruptions has been greatly exaggerated by [[sensationalist]] media.{{sfn|Karátson|Vereș|Gertisser|Magyari|2022|p=116}} Potential eruptions may be heralded by [[seismic swarm]]s caused by the ascent of magma, followed by deformation of the edifice and degassing in the last weeks and hours before the eruption.{{sfn|Cserép|Szemerédi|Harangi|Erdmann|2023|p=24}}
== Climate and vegetation ==
Ciomadul is located in a [[temperate climate]] zone. Rainfall reaches {{convert|800|-|1000|mm}}, resulting in strong erosion.{{sfn|Karátson|Telbisz|Harangi|Magyari|2013|p=46}} The annual mean temperature is {{convert|7.6|C}} at Sfântu Gheorghe, the nearest [[meteorological station]].{{sfn|Karátson|Thouret|Moriya|Lomoschitz|1999|p=180}} Around Sfânta Ana, July mean temperatures are {{convert|15|C}} and January temperatures are {{convert|-5|to|-6|C}}.{{sfn|Magyari|Vereș|Wennrich|Wagner|2014|p=281}}
While some [[glaciation]] occurred in the Carpathians during the [[ice age]]s, no glacial activity is recorded at Ciomadul. The volcano was unforested at that time,{{sfn|Magyari|Vereș|Wennrich|Wagner|2014|p=281}} with [[steppe]] and [[tundra]] vegetation comprising most of the reported flora.{{sfn|Magyari|Vereș|Wennrich|Wagner|2014|p=295}} [[Drill core]]s from the Mohoș peat bog have been used to reconstruct the past climate and hydrology of the area.{{sfn|Diaconu|Tanțău|Knorr|Borken|2019|p=9}}
Ciomadul is covered by [[beech]] and [[spruce]] forests.{{sfn|Tanțău|Reille|Beaulieu|Fărcaș|2003|p=114}} Around Lake Sfânta Ana, the vegetation consists mostly of ''[[Fagus sylvatica]]'' (common beech) and ''[[Picea abies]]'' (Norway spruce) woods. Other trees include ''[[Acer platanoides]]'' (Norway maple), ''[[Betula pendula]]'' (silver birch), ''[[Carpinus betulus]]'' (common hornbeam), ''[[Pinus sylvestris]]'' (Scots pine), ''[[Salix caprea]]'' (goat willow) and ''[[Salix cinerea]]'' (grey willow). A [[fen]] contains ''[[Carex lasiocarpa]]'' (slender sedge), ''[[Carex rostrata]]'' (bottle sedge), ''[[Lysimachia thyrsiflora]]'' (tufted loosestrife) and ''[[Sphagnum angustifolium]]'' (fine bogmoss).{{sfn|Magyari|Vereș|Wennrich|Wagner|2014|p=281}} At Mohoș, vegetation consists of ''[[Alnus glutinosa]]'' (common alder), ''[[Betula pendula]]'' and ''[[Salix]]''. The peat bog contains trees (''[[Pinus sylvestris]]'' and ''[[Betula pubescens]]'' (downy birch)) and [[Ericaceae]].{{sfn|Tanțău|Reille|Beaulieu|Fărcaș|2003|p=114}} The region of the volcano is a [[Site of Community Importance]]{{sfn|Sarbu|Aerts|Flot|Van Spanning|2018|p=174}} and some [[endangered species|endangered plant species]] have been identified in the Mohoș bog.{{sfn|Diaconu|Tanțău|Knorr|Borken|2019|p=2}}
== References == {{Reflist|20em|refs= <ref name=" HlavatskyiBakhmutov2020">{{Cite journal|last1=Hlavatskyi|first1=Dmytro V.|last2=Bakhmutov|first2=Vladimir G.|date=2020-09-01|title= Magnetostratigraphy and magnetic susceptibility of the best developed Pleistocene loess-palaeosol sequences of Ukraine: implications for correlation and proposed chronostratigraphic models|journal=Geological Quarterly|language=en|volume=64|issue=3|page=741|doi= 10.7306/gq.1544|issn=1641-7291|url= https://gq.pgi.gov.pl/article/view/26160/pdf|doi-access=free}}</ref> <ref name="Laumonier2018">{{cite journal |last1=Laumonier |first1=M. |last2=Karakas |first2=O. |last3=Bachmann |first3=O. |last4=Gaillard |first4=F. |last5=Lukács |first5=R. |last6=Seghedi |first6=I. |last7=Menand |first7=T. |last8=Harangi |first8=S. |title=Determining crustal melt and water contents from geophysics and experimental work to characterize a long dormant volcano: Ciomadul (Romania) |journal=AGUFM |date=December 2018 |volume=2018 |pages=DI42A–05–05 |language=en|bibcode=2018AGUFMDI42A..05L }}</ref> <ref name="VeresCosac2017">{{cite journal|last1=Vereș|first1=Daniel|last2=Cosac|first2=Marian|last3=Schmidt|first3=Christoph|last4=Murătoreanu|first4=George|last5=Hambach|first5=Ulrich|last6=Hubay|first6=Katalin|last7=Wulf|first7=Sabine|last8=Karátson|first8=David|title=New chronological constraints for Middle Palaeolithic (MIS 6/5-3) cave sequences in Eastern Transylvania, Romania|journal=Quaternary International|volume=485|pages=9–10|doi=10.1016/j.quaint.2017.07.015|bibcode=2018QuInt.485..103V|language=en|issn=1040-6182|year=2018|s2cid=133747654 |hdl=2437/271433|hdl-access=free}}</ref> <ref name="GVP">{{Cite GVP|vn=210801|name=South Harghita Mountains}}</ref> <ref name="DanisikSchmitt">{{Cite journal|last1=Danišík|first1=Martin|last2=Schmitt|first2=Axel K.|last3=Stockli|first3=Daniel F.|last4=Lovera|first4=Oscar M.|last5=Dunkl|first5=István|last6=Evans|first6=Noreen J.|title=Application of combined U-Th-disequilibrium/U-Pb and (U-Th)/He zircon dating to tephrochronology|journal=Quaternary Geochronology|volume=40|pages=23–32|doi=10.1016/j.quageo.2016.07.005|date=May 2017|doi-access=free|bibcode=2017QuGeo..40...23D }}</ref> <ref name="WulfFedorowicz2016">{{Cite journal|last1=Wulf|first1=Sabine|last2=Fedorowicz|first2=Stanis��aw|last3=Vereș|first3=Daniel|last4=Łanczont|first4=Maria|last5=Karátson|first5=Dávid|last6=Gertisser|first6=Ralf|last7=Bormann|first7=Marc|last8=Magyari|first8=Enikö|last9=Appelt|first9=Oona|date=2016-08-01|title=The 'Roxolany Tephra' (Ukraine) − new evidence for an origin from Ciomadul volcano, East Carpathians|journal=Journal of Quaternary Science|language=en|volume=31|issue=6|page=574|doi=10.1002/jqs.2879|bibcode=2016JQS....31..565W|s2cid=133260427 |issn=1099-1417|url=http://eprints.keele.ac.uk/1809/1/Gert_Wulf-et-al%202016-Roxolany.pdf}}</ref> <ref name="NovákHarangi2012">{{Cite journal|last1=Novák|first1=A.|last2=Harangi|first2=Sz.|last3=Kiss|first3=B.|last4=Szarka|first4=L.|last5=Molnár|first5=Cs.|date=2012-04-01|title=Combined magnetotelluric and petrologic constrains for the nature of the magma storage system beneath the Ciomad volcano (SE Carpathians)|journal=EGU General Assembly Conference Abstracts|bibcode=2012EGUGA..14.7637N|volume=14|page=7637}}</ref> <ref name="KaratsonWulf2016">{{Cite journal|last1=Karátson|first1=Dávid|last2=Wulf|first2=Sabine|last3=Vereș|first3=Daniel|last4=Gertisser|first4=Ralf|last5=Telbisz|first5=Tamás|last6=Magyari|first6=Enikö|date=2016-04-01|title=Paleo-geomorphic evolution of the Ciomad volcano (East Carpathians, Romania) using integrated volcanological, stratigraphical and radiometric data|journal=EGU General Assembly Conference Abstracts|bibcode=2016EGUGA..1811738K|volume=18|pages=EPSC2016–11738}}</ref> <ref name="KisIonescu2016">{{Cite journal|last1=Kis|first1=Boglárka-Mercedesz|last2=Ionescu|first2=Artur|last3=Harangi|first3=Szabolcs|last4=Palcsu|first4=László|last5=Etiope|first5=Giuseppe|last6=Baciu|first6=Călin|date=2016-04-01|title=Gas geochemical survey of long dormant Ciomadul volcano (South Harghita Mts., Romania): constraints on the flux and origin of fluids|journal=EGU General Assembly Conference Abstracts|bibcode=2016EGUGA..18.9576K|volume=18|pages=EPSC2016–9576}}</ref> }}
=== Bibliography === {{refbegin}} * {{cite journal |last1=Besutiu |first1=Lucian |last2=Szakács |first2=Alexandru |last3=Zlagnean |first3=Luminița |last4=Isac |first4=Anca |last5=Romanescu |first5=Dragomir |title=On the uncertainty of geophysical data interpretation in volcanic areas through a case study: Ciomad Volcano |journal=Physics of the Earth and Planetary Interiors |date=1 October 2021 |volume=319 |article-number=106781 |doi=10.1016/j.pepi.2021.106781 |bibcode=2021PEPI..31906781B |url=https://www.sciencedirect.com/science/article/pii/S0031920121001394 |language=en |issn=0031-9201|url-access=subscription }} * {{cite journal |last1=Cserép |first1=Barbara |last2=Szemerédi |first2=Máté |last3=Harangi |first3=Szabolcs |last4=Erdmann |first4=Saskia |last5=Bachmann |first5=Olivier |last6=Dunkl |first6=István |last7=Seghedi |first7=Ioan |last8=Mészáros |first8=Katalin |last9=Kovács |first9=Zoltán |last10=Virág |first10=Attila |last11=Ntaflos |first11=Theodoros |last12=Schiller |first12=David |last13=Molnár |first13=Kata |last14=Lukács |first14=Réka |title=Constraints on the pre-eruptive magma storage conditions and magma evolution of the 56–30 ka explosive volcanism of Ciomadul (East Carpathians, Romania) |journal=Contributions to Mineralogy and Petrology |date=December 2023 |volume=178 |issue=12 |page=96 |doi=10.1007/s00410-023-02075-z |language=en|doi-access=free |bibcode=2023CoMP..178...96C |hdl=20.500.11850/646219 |hdl-access=free }} * {{cite journal |last1=Diaconu |first1=Andrei-Cosmin |last2=Tanțău |first2=Ioan |last3=Knorr |first3=Klaus-Holger |last4=Borken |first4=Werner |last5=Feurdean |first5=Angelica |last6=Panait |first6=Andrei |last7=Gałka |first7=Mariusz |title=A multi-proxy analysis of hydroclimate trends in an ombrotrophic bog over the last millennium in the Eastern Carpathians of Romania |journal=Palaeogeography, Palaeoclimatology, Palaeoecology |volume=538 |article-number=109390 |doi=10.1016/j.palaeo.2019.109390 |bibcode=2020PPP...53809390D |issn=0031-0182|year=2019|s2cid=210314054 }} * {{Cite journal|last1=Harangi|first1=Szabolcs|last2=Lukács|first2=R.|last3=Schmitt|first3=A. K.|last4=Dunkl|first4=I.|last5=Molnár|first5=K.|last6=Kiss|first6=B.|last7=Seghedi|first7=I.|last8=Novothny|first8=Á.|last9=Molnár|first9=M.|date=2015-08-15|title=Constraints on the timing of Quaternary volcanism and duration of magma residence at Ciomad volcano, east–central Europe, from combined U–Th/He and U–Th zircon geochronology|journal=Journal of Volcanology and Geothermal Research|volume=301|pages=66–80|doi=10.1016/j.jvolgeores.2015.05.002|bibcode=2015JVGR..301...66H}} * {{Cite journal|last1=Harangi|first1=Szabolcs|last2=Molnár|first2=M|last3=Vinkler|first3=A P|last4=Kiss|first4=B|last5=Jull|first5=A J T|last6=Leonard|first6=A G|date=2010-08-01|title=Radiocarbon Dating of the Last Volcanic Eruptions of Ciomad Volcano, Southeast Carpathians, Eastern-Central Europe|url=https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/3648|journal=Radiocarbon|volume=52|issue=3|pages=1498–1507|issn=0033-8222|doi=10.1017/S0033822200046580|doi-access=free|bibcode=2010Radcb..52.1498H }} * {{Cite journal|last1=Harangi|first1=Szabolcs|last2=Novák|first2=A.|last3=Kiss|first3=B.|last4=Seghedi|first4=I.|last5=Lukács|first5=R.|last6=Szarka|first6=L.|last7=Wesztergom|first7=V.|last8=Metwaly|first8=M.|last9=Gribovszki|first9=K.|date=2015-01-01|title=Combined magnetotelluric and petrologic constrains for the nature of the magma storage system beneath the Late Pleistocene Ciomad volcano (SE Carpathians)|journal=Journal of Volcanology and Geothermal Research|volume=290|pages=82–96|doi=10.1016/j.jvolgeores.2014.12.006|bibcode=2015JVGR..290...82H}} * {{Cite journal|last1=Harangi|first1=Szabolcs|last2=Sági|first2=Tamás|last3=Seghedi|first3=Ioan|last4=Ntaflos|first4=Theodoros|date=2013-11-01|title=Origin of basaltic magmas of Perșani volcanic field, Romania: A combined whole rock and mineral scale investigation|journal=[[Lithos (journal)|Lithos]]|series=Magmatic response to the post-accretionary orogenesis within Alpine–Himalayan belt|volume=180–181|pages=43–57|doi=10.1016/j.lithos.2013.08.025|bibcode=2013Litho.180...43H|url=http://real.mtak.hu/9803/1/LITHOS_Persani_Harangi_uncorrected_proof.pdf}} * {{cite journal |last1=Harangi |first1=Szabolcs |last2=Molnár |first2=Kata |last3=Schmitt |first3=Axel K. |last4=Dunkl |first4=István |last5=Seghedi |first5=Ioan |last6=Novothny |first6=Ágnes |last7=Molnár |first7=Mihály |last8=Kiss |first8=Balázs |last9=Ntaflos |first9=Theodoros |last10=Mason |first10=Paul R. D. |last11=Lukács |first11=Réka |title=Fingerprinting the Late Pleistocene tephras of Ciomad volcano, eastern–central Europe |journal=Journal of Quaternary Science |date=2020 |volume=35 |issue=1–2 |pages=232–244 |doi=10.1002/jqs.3177 |bibcode=2020JQS....35..232H |language=en |issn=1099-1417|doi-access=free |hdl=10831/46360 |hdl-access=free }} * {{Cite journal|last1=Karátson|first1=Dávid|last2=Telbisz|first2=Tamás|last3=Harangi|first3=Szabolcs|last4=Magyari|first4=Enikő|last5=Dunkl|first5=István|last6=Kiss|first6=Balázs|last7=Jánosi|first7=Csaba|last8=Vereș|first8=Daniel|last9=Braun|first9=Mihály|date=2013-04-01|title=Morphometrical and geochronological constraints on the youngest eruptive activity in East-Central Europe at the Ciomad (Csomád) lava dome complex, East Carpathians|journal=Journal of Volcanology and Geothermal Research|volume=255|pages=43–56|doi=10.1016/j.jvolgeores.2013.01.013|bibcode=2013JVGR..255...43K|doi-access=free}} * {{Cite journal|last1=Karátson|first1=Dávid|last2=Thouret|first2=Jean-Claude|last3=Moriya|first3=Ichio|last4=Lomoschitz|first4=Alejandro|date=1999|title=Erosion calderas: origins, processes, structural and climatic control|journal=Bulletin of Volcanology|volume=61|issue=3|pages=174–193|doi=10.1007/s004450050270|bibcode=1999BVol...61..174K|s2cid=129382477|issn=0258-8900}} * {{cite journal |last1=Karátson |first1=D. |last2=Telbisz |first2=T. |last3=Dibacto |first3=S. |last4=Lahitte |first4=P. |last5=Szakács |first5=A. |last6=Vereș |first6=D. |last7=Gertisser |first7=R. |last8=Jánosi |first8=Cs. |last9=Timár |first9=G. |title=Eruptive history of the Late Quaternary Ciomad (Csomád) volcano, East Carpathians, part II: magma output rates |journal=Bulletin of Volcanology |date=29 March 2019 |volume=81 |issue=4 |page=28 |doi=10.1007/s00445-019-1287-8 |bibcode=2019BVol...81...28K |language=en |issn=1432-0819|doi-access=free |hdl=10831/46310 |hdl-access=free }} * {{Cite journal|last1=Karátson|first1=D.|last2=Wulf|first2=S.|last3=Vereș|first3=D.|last4=Magyari|first4=E. K.|last5=Gertisser|first5=R.|last6=Timar-Gabor|first6=A.|last7=Novothny|first7=Á.|last8=Telbisz|first8=T.|last9=Szalai|first9=Z.|date=2016-06-01|title=The latest explosive eruptions of Ciomad (Csomád) volcano, East Carpathians – A tephrostratigraphic approach for the 51–29 ka BP time interval|journal=Journal of Volcanology and Geothermal Research|volume=319|pages=29–51|doi=10.1016/j.jvolgeores.2016.03.005|bibcode=2016JVGR..319...29K|url=http://real.mtak.hu/47599/1/Karatson_etal_2016_MEK_u.pdf}} * {{Cite book |url=https://link.springer.com/10.1007/978-3-030-89140-4 |title=Ciomad (Csomád), The Youngest Volcano in the Carpathians: Volcanism, Palaeoenvironment, Human Impact |date=2022 |publisher=Springer International Publishing |isbn=978-3-030-89139-8 |editor-last=Karátson |editor-first=Dávid |location=Cham |language=en |doi=10.1007/978-3-030-89140-4 |s2cid=249208223 |editor-last2=Vereș |editor-first2=Daniel |editor-last3=Gertisser |editor-first3=Ralf |editor-last4=Magyari |editor-first4=Enikő K. |editor-last5=Jánosi |editor-first5=Csaba |editor-last6=Hambach |editor-first6=Ulrich}} * {{cite journal|last1=Kis|first1=Boglárka-Mercédesz|last2=Ionescu|first2=Artur|last3=Cardellini|first3=Carlo|last4=Harangi|first4=Szabolcs|last5=Baciu|first5=Călin|last6=Caracausi|first6=Antonio|last7=Viveiros|first7=Fátima|title=Quantification of carbon dioxide emissions of Ciomad, the youngest volcano of the Carpathian-Pannonian Region (Eastern-Central Europe, Romania)|journal=Journal of Volcanology and Geothermal Research|date=15 July 2017|volume=341|pages=119–130|doi=10.1016/j.jvolgeores.2017.05.025|bibcode=2017JVGR..341..119K|language=en|issn=0377-0273}} * {{Cite journal|last1=Kiss|first1=Balázs|last2=Harangi|first2=Szabolcs|last3=Ntaflos|first3=Theodoros|last4=Mason|first4=Paul R. D.|last5=Pál-Molnár|first5=Elemér|date=2014-03-05|title=Amphibole perspective to unravel pre-eruptive processes and conditions in volcanic plumbing systems beneath intermediate arc volcanoes: a case study from Ciomad volcano (SE Carpathians)|journal=Contributions to Mineralogy and Petrology|language=en|volume=167|issue=3|page=986|doi=10.1007/s00410-014-0986-6|bibcode=2014CoMP..167..986K|s2cid=62793874|issn=0010-7999|url=http://real.mtak.hu/21585/1/Amfibol_CMP2014_uncorrected%20proof2.pdf}} * {{cite journal |last1=Lahitte |first1=P. |last2=Dibacto |first2=S. |last3=Karátson |first3=D. |last4=Gertisser |first4=R. |last5=Vereș |first5=D. |title=Eruptive history of the Late Quaternary Ciomad (Csomád) volcano, East Carpathians, part I: timing of lava dome activity |journal=Bulletin of Volcanology |date=29 March 2019 |volume=81 |issue=4 |page=27 |doi=10.1007/s00445-019-1286-9 |bibcode=2019BVol...81...27L |s2cid=134372465 |url=https://link.springer.com/article/10.1007/s00445-019-1286-9 |language=en |issn=1432-0819}} * {{cite journal |last1=Laumonier |first1=M. |last2=Karakas |first2=O. |last3=Bachmann |first3=O. |last4=Gaillard |first4=F. |last5=Lukács |first5=R. |last6=Seghedi |first6=I. |last7=Menand |first7=T. |last8=Harangi |first8=S. |title=Evidence for a persistent magma reservoir with large melt content beneath an apparently extinct volcano |journal=Earth and Planetary Science Letters |date=1 September 2019 |volume=521 |pages=79–90 |doi=10.1016/j.epsl.2019.06.004 |bibcode=2019E&PSL.521...79L |language=en |issn=0012-821X|doi-access=free }} * {{cite journal |last1=Lukács |first1=R. |last2=Caricchi |first2=L. |last3=Schmitt |first3=A. K. |last4=Bachmann |first4=O. |last5=Karakas |first5=O. |last6=Guillong |first6=M. |last7=Molnár |first7=K. |last8=Seghedi |first8=I. |last9=Harangi |first9=Sz. |title=Zircon geochronology suggests a long-living and active magmatic system beneath the Ciomad volcanic dome field (eastern-central Europe) |journal=Earth and Planetary Science Letters |date=1 July 2021 |volume=565 |article-number=116965 |doi=10.1016/j.epsl.2021.116965 |bibcode=2021E&PSL.56516965L |s2cid=235513513 |language=en |issn=0012-821X|doi-access=free |hdl=10831/82855 |hdl-access=free }} * {{Cite journal|last1=Magyari|first1=E. K.|last2=Vereș|first2=D.|last3=Wennrich|first3=V.|last4=Wagner|first4=B.|last5=Braun|first5=M.|last6=Jakab|first6=G.|last7=Karátson|first7=D.|last8=Pál|first8=Z.|last9=Ferenczy|first9=Gy|date=2014-12-15|title=Vegetation and environmental responses to climate forcing during the Last Glacial Maximum and deglaciation in the East Carpathians: attenuated response to maximum cooling and increased biomass burning|journal=Quaternary Science Reviews|series=Dating, Synthesis, and Interpretation of Palaeoclimatic Records and Model-data Integration: Advances of the INTIMATE project (INTegration of Ice core, Marine and TErrestrial records, COST Action ES0907)|volume=106|pages=278–298|doi=10.1016/j.quascirev.2014.09.015|bibcode=2014QSRv..106..278M|url=http://real.mtak.hu/17097/1/Magyari%20et%20al%20QSR%20in%20press.pdf}} * {{Cite web|last=Mitrofan|first=Horia|url=https://www.geothermal-energy.org/pdf/IGAstandard/WGC/2000/R0630.PDF|title=Tușnad-Băi – A Geothermal System Associated With The Most Recent Volcanic Eruption in Romania|date=2000|publisher=IGA Geothermal Papers Online Database|website=pangea.stanford.edu|access-date=2016-12-19}} * {{cite journal|last1=Molnár|first1=Kata|last2=Harangi|first2=Szabolcs|last3=Lukács|first3=Réka|last4=Dunkl|first4=István|last5=Schmitt|first5=Axel K.|last6=Kiss|first6=Balázs|last7=Garamhegyi|first7=Tamás|last8=Seghedi|first8=Ioan|title=The onset of the volcanism in the Ciomad Volcanic Dome Complex (Eastern Carpathians): Eruption chronology and magma type variation|journal=Journal of Volcanology and Geothermal Research|volume=354|pages=39–56|date=February 2018|doi=10.1016/j.jvolgeores.2018.01.025|bibcode=2018JVGR..354...39M|language=en|issn=0377-0273|doi-access=free|hdl=10831/67106|hdl-access=free}} * {{cite journal |last1=Molnár |first1=Kata |last2=Lukács |first2=Réka |last3=Dunkl |first3=István |last4=Schmitt |first4=Axel K. |last5=Kiss |first5=Balázs |last6=Seghedi |first6=Ioan |last7=Szepesi |first7=János |last8=Harangi |first8=Szabolcs |title=Episodes of dormancy and eruption of the Late Pleistocene Ciomad volcanic complex (Eastern Carpathians, Romania) constrained by zircon geochronology |journal=Journal of Volcanology and Geothermal Research |date=15 March 2019 |volume=373 |pages=133–147 |doi=10.1016/j.jvolgeores.2019.01.025 |bibcode=2019JVGR..373..133M |s2cid=96519681 |url=https://www.sciencedirect.com/science/article/pii/S0377027318304839 |language=en |issn=0377-0273|url-access=subscription }} * {{cite journal |last1=Molnár |first1=Kata |last2=Czuppon |first2=György |last3=Palcsu |first3=László |last4=Benkó |first4=Zsolt |last5=Lukács |first5=Réka |last6=Kis |first6=Boglárka-Mercédesz |last7=Németh |first7=Bianca |last8=Harangi |first8=Szabolcs |title=Noble gas geochemistry of phenocrysts from the Ciomad volcanic dome field (Eastern Carpathians) |journal=Lithos |date=1 August 2021 |volume=394-395 |article-number=106152 |doi=10.1016/j.lithos.2021.106152 |bibcode=2021Litho.39406152M |s2cid=233566261 |language=en |issn=0024-4937|doi-access=free |hdl=10831/110691 |hdl-access=free }} * {{Cite journal|last1=Sarbu|first1=Serban M|last2=Aerts|first2=Joost|first3=Jean-François|last3=Flot|last4=Van Spanning|first4=Rob J.M.|first5=Călin|last5=Baciu|first6=Artur|last6=Ionescu|last7=Kis|first7=Boglárka M.|first8=Reka|last8=Incze|first9=Sándor|last9=Sikó-Barabási|date=2018|title=Sulfur Cave (Romania), an extreme environment with microbial mats in a CO<sub>2</sub>-H<sub>2</sub>S/O<sub>2</sub> gas chemocline dominated by mycobacteria|journal=International Journal of Speleology|language=en|volume=47|issue=2|pages=173–187|doi=10.5038/1827-806X.47.2.2164|issn=0392-6672|doi-access=free|hdl=10831/67487|hdl-access=free}} * {{Cite journal|last1=Szakács|first1=Alexandru|last2=Seghedi|first2=Ioan|last3=Pécskay|first3=Zoltán|last4=Mirea|first4=Viorel|date=2015-01-30|title=Eruptive history of a low-frequency and low-output rate Pleistocene volcano, Ciomad, South Harghita Mts., Romania|journal=Bulletin of Volcanology|language=en|volume=77|issue=2|page=12|doi=10.1007/s00445-014-0894-7|bibcode=2015BVol...77...12S|s2cid=129778845|issn=0258-8900}} * {{cite journal |last1=Szakács |first1=Alexandru |last2=Kovács |first2=István János |title=Is the most recently active volcano in the Carpathian-Pannonian Region capable of further eruptions? |journal=Journal of Volcanology and Geothermal Research |date=August 2023 |volume=440 |article-number=107868 |doi=10.1016/j.jvolgeores.2023.107868 |language=en|doi-access=free |bibcode=2023JVGR..44007868S }} * {{Cite journal|last1=Tanțău|first1=Ioan|last2=Reille|first2=Maurice|last3=Beaulieu|first3=Jacques-Louis de|last4=Fărcaș|first4=Sorina|last5=Goslar|first5=Tomasz|last6=Paterne|first6=Martine|date=2003-08-05|title=Vegetation history in the Eastern Romanian Carpathians: pollen analysis of two sequences from the Mohoș crater|journal=Vegetation History and Archaeobotany|language=en|volume=12|issue=2|pages=113–125|doi=10.1007/s00334-003-0015-6|bibcode=2003VegHA..12..113T |s2cid=128908674|issn=0939-6314}} {{refend}}
==External links==
{{Commons category|Ciomad|Ciomadul}}
[[Category:Pleistocene lava domes]] [[Category:Volcanoes of Romania]] [[Category:Landforms of Romania]] [[Category:Natural history of Romania]] [[Category:Geography of Harghita County]] [[Category:Dormant volcanoes]]