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Petrogenesis of mafic collision zone magmatism: the Armenian sector of the Turkish-Iranian Plateau

Neill, I.; Meliksetian, K.; Allen, M.B.; Navasardyan, G.; Kuiper, K.

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I. Neill

K. Meliksetian

G. Navasardyan

K. Kuiper


The Turkish–Iranian Plateau grew after the Middle Miocene following the initial Paleogene Arabia–Eurasia collision. Authors attribute uplift to break-off of the southern Neo-Tethys slab beneath the Bitlis–Zagros Suture at ~ 15–10 Ma, coupled with continued plate convergence and regional crustal shortening. Since this time there has been an upsurge in mantle-derived collision magmatism over large parts of NW Iran, Eastern Anatolia and the Lesser Caucasus, potentially hundreds of kilometres from the site of southern Neo-Tethys slab break-off, > 10 Myr after the proposed break-off event. Whole rock elemental and Sr–Nd–Pb–Hf isotope data are presented for < 3 Ma trachy-basalt to trachy-basaltic andesite lavas erupted in Armenia in the South Caucasus. Samples formed by < 5% melting of fertile subduction-modified spinel-facies lithospheric mantle, and few display elemental or isotopic evidence for contamination by the 45-km thick Mesozoic–Paleogene arc crust or South Armenian Block continental crust. Recent magmatic activity in Armenia may not be a direct consequence of southern Neo-Tethys slab break-off 300–450 km away, beneath the Bitlis Suture. Late Miocene break-off of a second (northern Neo-Tethys) slab beneath the Pontide Arc may have allowed asthenospheric upwelling over a wider area than was affected by southern Neo-Tethyan break-off. However, whole-scale delamination of mantle lithosphere is ruled out due to the modest degrees of partial melting, a lack of asthenospheric components and limited crustal involvement in magmatism. Small-scale sub-lithospheric convection may be complementary to break-off, causing localised removal of lithospheric mantle and aiding the occurrence of melting for a significant time interval after the break-off event(s). Collision magmas such as those in Armenia represent mantle-derived additions to continental crust, enriched in incompatible elements but with Th/La ratios ≤ 0.2, much lower than those calculated for continental crust (0.25–0.3). Collision magmatism in Turkic-style orogens must be balanced by infra-crustal recycling and delamination to produce bulk continental crust.


Neill, I., Meliksetian, K., Allen, M., Navasardyan, G., & Kuiper, K. (2015). Petrogenesis of mafic collision zone magmatism: the Armenian sector of the Turkish-Iranian Plateau. Chemical Geology, 403, 24-41.

Journal Article Type Article
Acceptance Date Mar 12, 2015
Publication Date May 1, 2015
Deposit Date Mar 13, 2015
Publicly Available Date Apr 2, 2015
Journal Chemical Geology
Print ISSN 0009-2541
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 403
Pages 24-41
Keywords Arabia–Eurasia collision, Armenia, Continental crust, Orogenic plateau, Radiogenic isotopes, Sub-lithospheric convection


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