Geochemistry and geochronology of the Neyshabur meta-volcanic rocks, Binalood mountains, NE Iran: witnesses of Paleo-Tethys rifting and closure

Hadi Karimi*, Gültekin Topuz, Lothar Ratschbacher, Chuanbo Shen, Jianhua Li

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Abstract: Geochemical and geochronologic data are presented for meta-mafic to meta-felsic rocks along the Paleo-Tethys Suture in the Binalood Mountains east of Neyshabur, NE Iran. The rocks have a late Cambrian age (U–Pb zircon, ~ 490 Ma) and were metamorphosed in the Early Jurassic (40Ar/39Ar amphibole and plagioclase, 199–192 Ma). The rocks of this suite are alkaline and sub-alkaline (tholeiitic). The alkaline rocks are enriched in light relative to heavy rare earth elements, and do not show depletion of high-field strength elements on primitive mantle-normalized multi-element diagrams; they are similar to ocean island basalts (OIB). The tholeiitic rocks are depleted in Nb and Ta and have higher MgO and lower TiO2 than the alkaline rocks. Both types have similar, high and variable 87Sr/86Sr(i) isotopic compositions of 0.7044 to 0.7082 and 143Nd/144Nd(i) values of 0.5118 to 0.5122. The alkaline rocks are lower-degree partial melts than the tholeiitic rocks and were generated at greater depths; they likely originated from a garnet pyroxenite-rich source. The spatial, temporal, and geochemical relationships of early Paleozoic meta-mafic to felsic rocks along the Paleo-Tethys Suture (e.g., Shahrud, Jajarm, Binalood, Torbat-e-Jam) substantiate the role of a mantle plume in continental breakup along the northern margin of Gondwana and a late Cambrian-Ordovician onset of rifting that resulted in the opening of the Paleo-Tethys Ocean. The Early Jurassic metamorphism post-dates its closure. Graphical abstract: (Figure presented.).

Original languageEnglish
Pages (from-to)285-302
Number of pages18
JournalInternational Journal of Earth Sciences
Volume113
Issue number2
DOIs
Publication statusPublished - Mar 2024

Bibliographical note

Publisher Copyright:
© The Author(s) 2023.

Funding

We thank J.A. Pfänder and B. Sperner for conducting the Ar/Ar measurements at ALF. H.K., L.R., and C.S. acknowledge funding by a DAAD doctoral scholarship, DFG project RA 442/40, and Natural Science Foundation of Hubei province grant no. 2021CFA031, respectively.

FundersFunder number
Deutscher Akademischer Austauschdienst
Deutsche ForschungsgemeinschaftRA 442/40
Natural Science Foundation of Hubei Province2021CFA031

    Keywords

    • Alkaline basalt
    • Binalood Mountains
    • Continental rifting
    • Iran
    • Mantle plume
    • Opening and closure of Paleo-Tethys Ocean

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