Isotopic dating of Neoproterozoic crustal growth in the Usambara Mountains of northeastern Tanzania: Evidence for coeval crust formation in the Mozambique Belt and the Arabian-Nubian Shield

M. A.H. Maboko, E. Nakamura

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

Granulite-facies orthogneisses of andesitic to dacitic composition in the Usambara Mountains of north eastern Tanzania yield a Sm-Nd whole rock isochron age of 815 ± 58 Ma and an initial ε(Nd) value of 4.1. This age is interpreted as dating Sm-Nd fractionation during extraction from the mantle and immediate subsequent crystallisation of the granulite protolith during an event of regional calc-alkaline magmatism in the area. Isotopic and geochemical characteristics of the rocks are consistent with a convergent margin setting for the magmatism with minimal contamination by older continental crust. The isotopic data from the Usambara Mountains demonstrate that Neoproterozoic crust formation in the Arabian-Nubian Shield and parts of the Mozambique Belt was broadly contemporaneous.

Original languageEnglish
Pages (from-to)227-242
Number of pages16
JournalPrecambrian Research
Volume113
Issue number3-4
DOIs
Publication statusPublished - Jan 31 2002

Keywords

  • Crust formation
  • Granulites
  • Mozambique Belt
  • Sm-Nd geochronology
  • Tanzania

ASJC Scopus subject areas

  • Geology
  • Geochemistry and Petrology

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