Contributions to Mineralogy and Petrology

, Volume 156, Issue 6, pp 765–784

Nd, Pb, and Sr isotope composition of Late Mesozoic to Quaternary intra-plate magmatism in NE-Africa (Sudan, Egypt): high-μ signatures from the mantle lithosphere

Authors

    • GeoForschungsZentrum Potsdam
    • Fachgebiet Mineralogie-Petrologie, Technische Universität Berlin
  • Gerhard Franz
    • Fachgebiet Mineralogie-Petrologie, Technische Universität Berlin
  • Rolf L. Romer
    • GeoForschungsZentrum Potsdam
  • Dieter Pudlo
    • Fachgebiet Mineralogie-Petrologie, Technische Universität Berlin
    • Faculty of Chemistry and Earth Sciences, Institute of Earth SciencesFriedrich-Schiller-Universität Jena
  • Peter Dulski
    • GeoForschungsZentrum Potsdam
Original Paper

DOI: 10.1007/s00410-008-0314-0

Cite this article as:
Lucassen, F., Franz, G., Romer, R.L. et al. Contrib Mineral Petrol (2008) 156: 765. doi:10.1007/s00410-008-0314-0

Abstract

The isotopic composition of mafic small-volume intra-plate magmatism constrains the compositions of the sub-continental mantle sources. The Nd, Pb, and Sr isotope signatures of widespread late Mesozoic to Quaternary intra-plate magmatism in NE Africa (Sudan, South Egypt) are surprisingly uniform and indicate the presence of a high-μ (μ = 238U/204Pb) source in the mantle. The rocks are characterized by small ranges in the initial isotopic composition of Nd, Pb, and Sr and most samples fall within ε Nd ca. 3–6, 206Pb/204Pb ca. 19.5–20.5, 207Pb/204Pb ca. 15.63–15.73, 208Pb/204Pb ca. 39–40 and 87Sr/86Sr ca. 0.7028–0.7034. We interpret this reservoir as lithospheric mantle that formed beneath the Pan-African orogens and magmatic arcs from asthenospheric mantle, which was enriched in trace elements (U, Th, and light REE). Combining our new data set with published data of intra-plate magmatic rocks from the Arabian plate indicates two compositionally different domains of lithospheric mantle in NE-Africa–Arabia. The two domains are spatially related to the subdivision of the Pan-African orogen into a western section dominated by reworked cratonic basement (NE-Africa; high-μ lithospheric mantle) and an eastern section dominated by juvenile Pan-African basement (easternmost NE-Africa and Arabia; moderate μ lithospheric mantle). The compositions of the Pan-African lithospheric mantle and the MORB-type mantle of the Red Sea and Gulf of Aden spreading centers could explain the Nd–Pb-Sr isotopic compositions of the most pristine Afar flood basalts in Yemen and Ethiopia by mixtures of the isotopic composition of regional lithospheric and asthenospheric sources.

Keywords

NE-AfricaIntra-plate magmatismNd–Pb-Sr isotopesUpper mantle isotope compositionHigh-μ mantle

Supplementary material

410_2008_314_MOESM1_ESM.pdf (559 kb)
Electronic Appendix (PDF 559 kb)

Copyright information

© Springer-Verlag 2008