TY - JOUR
T1 - Zircon U-Pb geochronology and Nd isotope systematics of the Abas terrane, Yemen
T2 - Implications for Neoproterozoic crust reworking events
AU - Yeshanew, Fitsum G.
AU - Pease, Victoria
AU - Whitehouse, Martin J.
AU - Al-Khirbash, Salah
N1 - Funding Information:
Constructive reviews by Hugh Rollinson and Robert Stern are gratefully acknowledged. We thank the staff at the Swedish Museum of Natural History for the technical assistance. This project was supported by grants from the Swedish Research Council (VR dnr. 2009-4499) to MJW and VP. The Nordsim facility is a joint Nordic infrastructure. This is Nordsim contribution #408.
Publisher Copyright:
© 2015 Elsevier B.V.
PY - 2015/9/1
Y1 - 2015/9/1
N2 - 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.
AB - 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.
KW - Arabian Shield
KW - Nd isotopes
KW - Post-tectonic magmatism
KW - Precambrian crustal evolution
KW - U-Pb zircon
KW - Yemen
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U2 - 10.1016/j.precamres.2015.05.037
DO - 10.1016/j.precamres.2015.05.037
M3 - Article
AN - SCOPUS:84932629108
SN - 0301-9268
VL - 267
SP - 106
EP - 120
JO - Precambrian Research
JF - Precambrian Research
ER -