TY - JOUR
T1 - Hf isotopic composition of single zircons from Neoproterozoic arc volcanics and post-collision granites, Eastern Desert of Egypt
T2 - Implications for crustal growth and recycling in the Arabian-Nubian Shield
AU - Ali, Kamal A.
AU - Wilde, Simon A.
AU - Stern, Robert J.
AU - Moghazi, Abdel Kader M.
AU - Ameen, S. M.Mahbubul
N1 - Funding Information:
We dedicate this study to the memory of Dr. Ewais Moussa who worked extensively in the ED, and provided KAA with some key ED samples that were integrated in this study. He passed away in October 2, 2012 at age of 50. This work was supported by NSF-OISE grant 0821257 . The SHRIMP II facility in Perth is operated jointly by Curtin University, the University of Western Australia and the Geological Survey of Western Australia, with support from the Australian Research Council . The authors would like to thank the Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing for performing the Hf-isotope analyses. We sincerely thank two anonymous reviewers for their constructive comments and suggestions that greatly helped to improve the manuscript. Great thanks go to Editor Prof. Victoria Pease for handling the manuscript. This is UTD Geosciences contribution number #1238 and TIGeR publication # 463. This is a JEBEL contribution.
PY - 2013/12
Y1 - 2013/12
N2 - Zircon Hf isotopic compositions for Neoproterozoic igneous rocks in the Central Eastern Desert of Egypt are presented and interpreted. The Humr Akarim (633±7 and 603±9Ma)-Humrat Mukbid (625±8 and 619±8Ma) plutons are Early Ediacaran post-collsional subsolvus granites. Their zircon ages range from 0.57 to 0.71Ga, with high positive e{open}Hf(T) values of +4.0 to +11.9. Hf model ages (Hf-TDMc) of 0.81-1.3Ga, are close to the U-Pb crystallization ages. These isotopic characteristics, along with published whole-rock Nd isotopic data, indicate that the protoliths were juvenile. The Wadi Kareim and Wadi El-Dabbah metavolcano-sedimentary rocks are Cryogenian (~750Ma) arc-related metabasalts, meta-andesites and meta-tuffs. Their U-Pb zircon age populations range between 0.7-0.9, 0.9-1.5Ga and 2.0-3.0Ga. The youngest group represents magmatic zircons in the metavolcanics or reworked Neoproterozoic rocks in the metasediments. The 0.9-1.5Ga and 2.0-3.0Ga age groups are similar to those in pre-Neoproterozoic rocks that surround the Arabian-Nubian Shield and represent inherited or older detrital grains. The highly variable e{open}Hf(T) values (+23.5 to -35.0) and Hf-TDMc ages (0.78-3.8Ga) of Neoproterozoic zircons indicate that at least some of these magmas interacted with a pre-Neoproterozoic crustal source.
AB - Zircon Hf isotopic compositions for Neoproterozoic igneous rocks in the Central Eastern Desert of Egypt are presented and interpreted. The Humr Akarim (633±7 and 603±9Ma)-Humrat Mukbid (625±8 and 619±8Ma) plutons are Early Ediacaran post-collsional subsolvus granites. Their zircon ages range from 0.57 to 0.71Ga, with high positive e{open}Hf(T) values of +4.0 to +11.9. Hf model ages (Hf-TDMc) of 0.81-1.3Ga, are close to the U-Pb crystallization ages. These isotopic characteristics, along with published whole-rock Nd isotopic data, indicate that the protoliths were juvenile. The Wadi Kareim and Wadi El-Dabbah metavolcano-sedimentary rocks are Cryogenian (~750Ma) arc-related metabasalts, meta-andesites and meta-tuffs. Their U-Pb zircon age populations range between 0.7-0.9, 0.9-1.5Ga and 2.0-3.0Ga. The youngest group represents magmatic zircons in the metavolcanics or reworked Neoproterozoic rocks in the metasediments. The 0.9-1.5Ga and 2.0-3.0Ga age groups are similar to those in pre-Neoproterozoic rocks that surround the Arabian-Nubian Shield and represent inherited or older detrital grains. The highly variable e{open}Hf(T) values (+23.5 to -35.0) and Hf-TDMc ages (0.78-3.8Ga) of Neoproterozoic zircons indicate that at least some of these magmas interacted with a pre-Neoproterozoic crustal source.
KW - Arabian-Nubian Shield
KW - Egypt
KW - Hf-isotopes
KW - Neoproterozoic crust
KW - Single-zircon Hf-isotopes
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U2 - 10.1016/j.precamres.2013.05.007
DO - 10.1016/j.precamres.2013.05.007
M3 - Article
AN - SCOPUS:84889602463
SN - 0301-9268
VL - 239
SP - 42
EP - 55
JO - Precambrian Research
JF - Precambrian Research
ER -