Single zircon Hf-O isotope constraints on the origin of A-type granites from the Jabal Al-Hassir ring complex, Saudi Arabia

Kamal A. Ali, Adel A. Surour, Martin J. Whitehouse, Arild Andresen

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

The Jabal Al-Hassir ring complex in the southern Arabian Shield is an alkaline granite complex comprising an inner core of biotite granite that outwardly becomes a porphyritic sodic-calcic amphibole (ferrobarroisite-katophorite) granite. A combined study of mineral chemistry and single zircon Hf-O zircon isotope analyses was carried out to infer the magma sources of the Neoproterozoic post-collisional A-type granitoids in Saudi Arabia. The granitic rocks show high positive initial e{open}Hf(t) values of +7.0 to +10.3 and δ18O values of +5.8‰ to +7.4‰ that are consistent with melting of a juvenile crustal protolith that was formed during the Neoproterozoic assembly of the Arabian-Nubian Shield (ANS). Crustal-model ages (Hf-tNC) of 0.71-0.94Ga indicate minor contribution from an older continental crust in the formation of the Jabal Al-Hassir granitic rocks (crystallization age=620±3Ma), but any such component is likely to be Neoproterozoic in age. Temperature and oxygen fugacity (f{hook}O2) estimates suggested that the Jabal Al-Hassir A-type granite magma was generated at high temperature (820-1050°C) and low f{hook}O2. Geochemical characteristics (e.g., low f{hook}O2), geochronological data, and Hf and O isotope compositions, indicate that the magmas of the Neoproterozoic A-type granites of the Jabal Al-Hassir ring complex were likely generated by crustal partial melting of a juvenile Neoproterozoic lower crustal tholeiitic rocks, following collision between East and West Gondwana in the final stages of the evolution of the Arabian Shield.

Original languageEnglish
Pages (from-to)131-147
Number of pages17
JournalPrecambrian Research
Volume256
DOIs
Publication statusPublished - Jan 1 2015
Externally publishedYes

Keywords

  • A-type granites
  • Arabian-Nubian Shield
  • Neoproterozoic juvenile crust
  • Ring complex
  • Single zircon Hf-O isotopes

ASJC Scopus subject areas

  • Geology
  • Geochemistry and Petrology

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