TY - JOUR
T1 - Single zircon Hf-O isotope constraints on the origin of A-type granites from the Jabal Al-Hassir ring complex, Saudi Arabia
AU - Ali, Kamal A.
AU - Surour, Adel A.
AU - Whitehouse, Martin J.
AU - Andresen, Arild
N1 - Funding Information:
We appreciate the assistance of Kerstin Lindén and Lev Ilyinsky during the isotopic studies at the Swedish Museum of Natural History. We would like to thank Prof. Ahmed Hassan Ahmed for his kind assistance on the electron microprobe and Prof. Mark G. Steltenpohl for his constructive comments on the first draft of the manuscript. We are grateful to two anonymous reviewers and Editor-in-Chief Prof. Randall Parrish for critical reviews that improved this manuscript. The NordSIM ion microprobe facility is financed and operated under an agreement between the research councils of Denmark, Sweden, and the Geological Survey of Finland and the Swedish Museum of Natural History. This is Nordsim contribution # 385.
Publisher Copyright:
© 2014 Elsevier B.V.
PY - 2015/1/1
Y1 - 2015/1/1
N2 - 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.
AB - 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.
KW - A-type granites
KW - Arabian-Nubian Shield
KW - Neoproterozoic juvenile crust
KW - Ring complex
KW - Single zircon Hf-O isotopes
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U2 - 10.1016/j.precamres.2014.11.007
DO - 10.1016/j.precamres.2014.11.007
M3 - Article
AN - SCOPUS:84911889648
SN - 0301-9268
VL - 256
SP - 131
EP - 147
JO - Precambrian Research
JF - Precambrian Research
ER -