Crustal evolution and recycling in the northern Arabian-Nubian Shield: New perspectives from zircon Lu-Hf and U-Pb systematics

Navot Morag*, Dov Avigad, Axel Gerdes, Elena Belousova, Yehudit Harlavan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

146 Scopus citations

Abstract

This paper presents laser-ablation (MC)-ICP-MS single-zircon Hf isotopic data coupled with U-Pb geochronology from a unique rock inventory in southern Israel, recording ca. 300m.y. of Neoproterozoic crustal evolution in the northern Arabian-Nubian Shield (ANS). The early, island-arc magmatic cycle in this area is recorded by detrital zircons from arc-derived metasediments, dated between 870 and 760Ma, and by ca. 790 and 740Ma orthogneisses. Zircon e{open}Hf(t) values from these rocks are all positive, supporting previous isotopic evidence for the overall juvenile nature of northern ANS crust. Nonetheless, detrital zircons from the metasedimentary units display a wide range of e{open}Hf(t) values between +1 and +13. The lower values in this range suggest some contribution from an older crustal component. The involvement of pre-Neoproterozoic crustal component is also indicated by the occurrence of rare zircons with pre-Neoproterozoic ages and/or negative e{open}Hf(t) values in younger (post-collisional) magmas that intrude the arc sequence. Arc accretion was followed by a period of ∼60m.y. of relative igneous tranquility interrupted only by the emplacement of local basic dike swarm at ca. 705Ma. Average zircon e{open}Hf(t) value of +10 found in one of these dikes indicates a depleted mantle source possibly implying a mid-Neoproterozoic extensional phase. The later, post-collisional magmatic cycle marks the transition of the accreted arc complexes into a mature continental crust. It consists of voluminous 680-600Ma granitoid plutons of calc-alkaline affinity, and subordinate 610-580Ma intrusions of alkaline affinity. Average zircon e{open}Hf(t) values in these post-collisional rocks are all positive and range between +6 and +9, compatible with both mantle source and juvenile crust reworking.

Original languageAmerican English
Pages (from-to)101-116
Number of pages16
JournalPrecambrian Research
Volume186
Issue number1-4
DOIs
StatePublished - Apr 2011

Bibliographical note

Funding Information:
Special thanks are due to Keren Kolodner, who allowed us to use her zircon samples and data. We are grateful to S.A. Wilde and R.J. Stern for critical reviews that considerably improved this manuscript. This research was funded by the Israel Ministry of Infrastructures. The first author's visit to the laboratory in GUF was funded by a Minerva Stiftung short-term research grant.

Keywords

  • Arabian-Nubian Shield
  • Crustal evolution
  • Hf isotopes
  • U-Pb geochronology
  • Zircon

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