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Evidence for an early-MORB to fore-arc evolution within the Zagros suture zone: Constraints from zircon U Pb geochronology and geochemistry of the Neyriz ophiolite (South Iran)

Monsef, Iman and Monsef, Reza and Mata, João and Zhang, Zhiyong and Pirouz, Mortaza and Rezaeian, Mahnaz and Esmaeili, Rasoul and Xiao, Wenjiao (2018) Evidence for an early-MORB to fore-arc evolution within the Zagros suture zone: Constraints from zircon U Pb geochronology and geochemistry of the Neyriz ophiolite (South Iran). Gondwana Research , 62 . pp. 287-305. ISSN 1342-937X . https://resolver.caltech.edu/CaltechAUTHORS:20180307-092316678

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Abstract

Late Cretaceous Neyriz ophiolite, as a part of the Outer Zagros Ophiolitic Belt, represents a remnant of the southern Neo-Tethyan oceanic lithosphere exposed along the Zagros suture zone in the south of Iran. Neyriz ophiolite is composed of dismembered lithological units including variably depleted mantle peridotites as well as intrusive and extrusive rocks preserving a geochemical evolution from mid-ocean ridge (MORB) to subduction-related (boninitic) signatures. Initially, the southern Neo-Tethyan oceanic lithosphere formed in the mid-ocean ridge spreading centre between the Arabian plate to the south west and the Eurasian plate to the north east. The inception of intra-oceanic subduction in the northern margin of the Arabian plate caused a slightly metasomatised supra-subduction-zone (SSZ) mantle lithosphere, producing MORB-like melts with a high degree of partial melting (~25–30%), and complementary depleted residual clinopyroxene (Cpx)-rich harzburgite. The zircon U-Pb geochronology for plagiogranite and gabbro intrusions reveals formation ages of 100.1 ± 2.3 Ma to 93.4 ± 1.3 Ma, respectively (Cenomanian). At a later stage, the rapid slab rollback and associated fore-arc spreading led to asthenospheric diapirism and arc-wedge mantle corner flow, which produced boninitic-like melts with advanced degrees of shallow partial melting (~35%), and ultra-depleted residual Cpx-poor harzburgites. The pervasive interaction between boninitic-like melts and refractory Cpx-poor harzburgites produced dunites as replacive lenses. Thus, this study postulates that Neyriz ophiolite formed from the Neo-Tethyan intra-oceanic subduction system, and preserves evidence of the evolution from an early-MORB oceanic crust to an extending fore-arc basin during subduction rollback processes. This tectonic environment is common in the Eastern Mediterranean region, where SSZ ophiolites have resulted in extended protoarc-forearc settings above subducted slabs.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.gr.2018.03.002DOIArticle
https://www.sciencedirect.com/science/article/pii/S1342937X1830056XPublisherArticle
ORCID:
AuthorORCID
Pirouz, Mortaza0000-0002-7569-492X
Additional Information:© 2018 International Association for Gondwana Research. Published by Elsevier B.V. Received 12 October 2017, Revised 4 March 2018, Accepted 5 March 2018, Available online 6 March 2018.
Subject Keywords:UPb dating; Neo-Tethys; Rollback; Neyriz ophiolite; Iran
Record Number:CaltechAUTHORS:20180307-092316678
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20180307-092316678
Official Citation:Iman Monsef, Reza Monsef, João Mata, Zhiyong Zhang, Mortaza Pirouz, Mahnaz Rezaeian, Rasoul Esmaeili, Wenjiao Xiao, Evidence for an early-MORB to fore-arc evolution within the Zagros suture zone: Constraints from zircon U-Pb geochronology and geochemistry of the Neyriz ophiolite (South Iran), Gondwana Research, Volume 62, 2018, Pages 287-305, ISSN 1342-937X, https://doi.org/10.1016/j.gr.2018.03.002. (http://www.sciencedirect.com/science/article/pii/S1342937X1830056X)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85171
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:07 Mar 2018 17:28
Last Modified:03 Oct 2019 19:27

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