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dc.contributor.author
Bindeman, Ilya N.
dc.contributor.author
Colón, D.P.
dc.contributor.author
Wotzlaw, Jörn-Frederik
dc.contributor.author
Stern, Richard
dc.contributor.author
Chiaradia, Massimo
dc.contributor.author
Guillong, Marcel
dc.date.accessioned
2021-02-25T10:13:16Z
dc.date.available
2021-02-24T09:52:50Z
dc.date.available
2021-02-25T10:13:16Z
dc.date.issued
2021-04
dc.identifier.issn
0377-0273
dc.identifier.other
10.1016/j.jvolgeores.2021.107173
en_US
dc.identifier.uri
http://hdl.handle.net/20.500.11850/471301
dc.description.abstract
Several kilometers of rapid uplift in the past 2–3 million years in the Greater Caucasus in Russia has produced world-class exposures of Pliocene-Pleistocene age granites and ignimbrites at the Tyrnyauz and Chegem volcanic centers just to the east of Europe's highest mountain and active volcano, Mount Elbrus. This represents one of the world's best-preserved examples of silicic magmatism in a continental collision environment. We report results of a multi-method zircon petrochronologic (U--Pb, O--Hf isotopes, trace elements) investigation of six ignimbrites, lavas, and associated granodioritic porphyries from these localities. We observe two pulses of magmatism at 2.92 and 1.98 Ma related to Chegem and Tyrnyauz, respectively. High precision CA-ID-TIMS dating of zircons from the top and bottom of the Chegem ignimbrite and its associated porphyry yield indistinguishable age spectra recording 160 kyr of magma assembly and differentiation, with 2.9181 ± 0.0014 Ma eruption age as is constrained by the youngest dated zircon population. Together with overlapping O and Hf isotopic values, this suggests that they represent a large volume of pre-eruptively homogenized magma with ~20% crystals. Zircons have isotopically diverse cores (δ18O = +3.4–6.7‰, εHf = +0.8 to +5.6) while the rims (+5.75 ± 0.20‰, εHf = 3.3 ± 0.7) are in isotopic equilibrium with associated unaltered glass and major phenocryst phases. The neighboring and younger ignimbrites and granites of the nearby Elbrus and Tyrnyauz centers have overlapping higher δ18O and lower εHf zircon values and cluster narrowly in age around 1.98 Ma, suggesting a common source for all these ignimbrites, likely in the Tyrnyauz area. Isotopic data for Chegem, Elbrus and Tyrnyauz zircons and rocks require the contribution of a high proportion (25–55%) of Paleozoic crust to magma petrogenesis. The origin of sudden spikes of voluminous silicic magmatism is further investigated using thermomechanical modeling of the collisional environment. We show that the voluminous silicic volcanism at Chegem, Tyrnyauz and Elbrus is best explained by heating of the lower crust by asthenospheric upwelling after a relict slab detached and sank into the mantle at approximately 5 Ma. This timing is coincident with both the beginning of rapid uplift of the Greater Caucasus and initiation of major volcanism. After this initial melting, continuing delamination of the lithosphere and lower crust from the subducting plate produced broad mantle melting and basaltic volcanism, potentially explaining continued regional-scale magmatism in both the Greater and Lesser Caucasus. © 2021 Elsevier
en_US
dc.language.iso
en
en_US
dc.publisher
Elsevier
en_US
dc.subject
Caucasus
en_US
dc.subject
Eldjurta Granite
en_US
dc.subject
Zayukovo
en_US
dc.subject
Elbrus
en_US
dc.subject
Tyrnyauz
en_US
dc.subject
Zircon
en_US
dc.subject
Oxygen isotopes
en_US
dc.subject
Hydrogen isotopes
en_US
dc.subject
Thermomechanical modeling
en_US
dc.title
Young Silicic Magmatism of the Greater Caucasus, Russia, with implication for its delamination origin based on zircon petrochronology and thermomechanical modeling
en_US
dc.type
Journal Article
dc.date.published
2021-01-23
ethz.journal.title
Journal of Volcanology and Geothermal Research
ethz.journal.volume
412
en_US
ethz.journal.abbreviated
J. volcanol. geotherm. res.
ethz.pages.start
107173
en_US
ethz.size
20 p.
en_US
ethz.identifier.wos
ethz.identifier.scopus
ethz.publication.place
Amsterdam
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::09656 - Chelle-Michou, Cyril / Chelle-Michou, Cyril
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::03958 - Bachmann, Olivier / Bachmann, Olivier
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::09656 - Chelle-Michou, Cyril / Chelle-Michou, Cyril
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02330 - Dep. Erdwissenschaften / Dep. of Earth Sciences::02725 - Institut für Geochemie und Petrologie / Institute of Geochemistry and Petrology::03958 - Bachmann, Olivier / Bachmann, Olivier
ethz.date.deposited
2021-02-24T09:53:00Z
ethz.source
SCOPUS
ethz.eth
yes
en_US
ethz.availability
Metadata only
en_US
ethz.rosetta.installDate
2021-02-25T10:13:30Z
ethz.rosetta.lastUpdated
2022-03-29T05:27:25Z
ethz.rosetta.versionExported
true
ethz.COinS
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