Zircon U–Pb geochronology and Nd isotope systematics of the Abas terrane, Yemen: Implications for Neoproterozoic crust reworking events
2015 (English)In: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 267, 106-120 p.Article in journal (Refereed) Published
High-spatial-resolution secondary-ion mass spectrometry (SIMS) U–Pb zircon ages, whole-rock Nd iso- topic 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. 790–725 Ma represented by granitic gneisses, the second clearly post-tectonic at c. 625–590 Ma. The oldest sample in the post-tectonic group is slightly deformed while younger samples are undeformed indicating that penetrative deformation ceased at c. 625 Ma in the Abas region. Whole-rock Nd (t) values between −11 and +0.8, Nd model ages of 1.70–1.13 Ga 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 εNd (t) reflects a change in magma source with increasing juvenile magma and diminishing crustal input during post-tectonic (625–590 Ma) 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.
Place, publisher, year, edition, pages
Elsevier, 2015. Vol. 267, 106-120 p.
Precambrian crustal evolution; Arabian Shield; Yemen; U-Pb zircon; Post-tectonic magmatism; Nd isotopes
Research subject The changing Earth
IdentifiersURN: urn:nbn:se:nrm:diva-1587DOI: 10.1016/j.precamres.2015.05.037OAI: oai:DiVA.org:nrm-1587DiVA: diva2:881858
FunderSwedish Research Council, VR dnr. 2009-4499