Zircon U-Pb geochronology and Nd isotope systematics of the Abas terrane, Yemen: Implications for Neoproterozoic crust reworking events

Fitsum G. Yeshanew, Victoria Pease, Martin J. Whitehouse, Salah Al-Khirbash

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

High-spatial-resolution secondary-ion mass spectrometry (SIMS) UPb zircon ages, whole-rock Nd isotopic and geochemical data are reported for granites and granitic gneisses from a traverse across the Abas terrane, Yemen, a part of the Precambrian basement of southern Arabian Peninsula. SIMS U-Pb dating identifies two magmatic episodes, the first at c. 790-725Ma represented by granitic gneisses, the second clearly post-tectonic at c. 625-590Ma. The oldest sample in the post-tectonic group is slightly deformed while younger samples are undeformed indicating that penetrative deformation ceased at c. 625Ma in the Abas region. Whole-rock Nd(t) values between -11 and +0.8, Nd model ages of 1.70-1.13Ga indicate a significant contribution of evolved continental material in the genesis of the Abas granitoids, unlike most of the juvenile Arabian-Nubian Shield (ANS), although there are few inherited zircons. Secular variation in e{open}Nd(t) reflects a change in magma source with increasing juvenile magma and diminishing crustal input during post-tectonic (625-590Ma) magmatism. The combination of subduction zone chemistry, absence of older rocks, paucity of inherited zircons, evolved Nd isotopic signatures and the I-type characteristics of the samples suggest that assimilation occurred at depth.

Original languageEnglish
Pages (from-to)106-120
Number of pages15
JournalPrecambrian Research
Volume267
DOIs
Publication statusPublished - Sep 1 2015

Keywords

  • Arabian Shield
  • Nd isotopes
  • Post-tectonic magmatism
  • Precambrian crustal evolution
  • U-Pb zircon
  • Yemen

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geology

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