Petrology and geochemistry of Plio-Quaternary high-Nb basalts from Shahr-e-Babak area:Insights into post-collision magmatic processes in the Kerman Cenozoic Magmatic Arc
DOI:
https://doi.org/10.1344/GeologicaActa2022.20.8Keywords:
High-Nb basalts, Post-collision, Metasomatized mantle wedge, Slab break-off, Kerman Cenozoic Magmatic ArcAbstract
Post-collision Pliocene-Quaternary basaltic rocks outcrop in the Kerman Cenozoic Magmatic Arc (KCMA) to the northwest and east of Shahr-e-Babak city. These porphyritic and vesicular basaltic rocks are composed essentially of clinopyroxene, olivine, and plagioclase. These basalts display alkaline affinity and negative Ta, Zr, Rb anomaly, but slightly negative Nb anomaly, relative to elements with similar compatibility, and positive Ba, K, Sr anomaly, suggesting their magma source related to subduction-accretion with implication of subducted slab derived components to the source. In the primitive mantle and chondrite normalized diagrams, these rocks show trace elements (except depletion in Nb, Ta) and Rare Earth Element (REE) patterns similar to the Ocean Island Basalts (OIB) and share trace and major element characteristics similar to High-Nb Basalts (HNBs). Geochemical analyses for major and trace elements suggest that the Shahr-e-Babak HNBs have undergone insignificant crustal contamination and minor olivine + Fe-Ti oxide ±clinopyroxene fractional crystallization. These HNBs derived from a partial melting (~5%) of garnet-peridotite mantle wedge, which have already metasomatized by overlying sediments, fluids, and adakitic (slab-derived) melts as major metasomatic agents in post-collision setting in the KCMA. We conclude that asthenospheric upwelling arising from slab break-off followed by the roll-back of subducting Neotethys slab also triggered metasomatized peridotite mantle wedge and caused its partial melting in the subduction zone.
Downloads
Published
Issue
Section
License
Copyright (c) 2022 Geologica Acta
This work is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
Copyright
Geologica Acta is the property of the UB, GEO3BCN, IDAEA and UAB. Geologica Acta must be cited for any partial or full reproduction. Papers are distributed under the Attribution-Share Alike Creative Commons License. This license allows anyone to reproduce and disseminate the content of the journal and even make derivative works crediting authorship and provenance and distributing possible derivative works under the same or an equivalent license.
Author Rights
Authors retain the copyright on their papers and are authorized to post them on their own web pages or institutional repositories. The copyright was retained by the journal from the year 2003 until 2009. In all cases, the complete citation and a link to the Digital Object Identifier (DOI) of the article must be included.
The authors can use excerpts or reproduce illustrations of their papers in other works without prior permission from Geologica Acta provided the source of the paper including the complete citation is fully acknowledged.