Tectonic significance of Late Neoproterozoic granites from the Tibesti massif in southern Libya inferred from Sr and Nd isotopes and U–Pb zircon data |
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Authors: | Ismail B. Suayah Jonathan S. Miller Brent V. Miller Tovah M. Bayer John J.W. Rogers |
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Affiliation: | Department of Geological Sciences, University of North Carolina, Chapel Hill, NC 27599–3315, United States |
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Abstract: | The Neoproterozoic crust of the Tibesti massif was stabilized by magmatism that included subduction-generated batholithic suites and post-orogenic granite plutons. All of the magmatism occurred in a period of about 20 million years centered around 550 Ma, and nearly all of the granites have initial 87Sr/86Sr ratios of about 0.706. The Wadi Yebigue pluton has U–Pb zircon ages of 563 Ma and 558 Ma on two different phases and εNd at 550 Ma from −0.5 to −2.2. These isotopic data and the geologic history of the massif suggest that granites in the Tibesti massif developed during and shortly after closure of a short-lived ocean basin that developed by fragmentation of pre-existing continental crust of the Saharan region. |
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Keywords: | Tibesti Neoproterozoic Sr isotopes Nd isotopes Zircon dating Confined orogen |
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