Isotope zonation in basement crustal blocks of southeastern China: Evidence for multiple terrane amalgamation

Abstract

Nd and Sr isotopic data for Mesozoic Yanshanian granites sampled across major NNE - trending faults in eastern Guangdong Province record conspicuous compositional variations in the crustal basement. Two principal crustal domains can be distinguished: Paleoproterozoic-dominated in the northwest and Mesoproterozoic-dominated in the southeast. Within the Mesoproterozoic-dominated domains, thin tectonic slivers of isotopically homogeneous Paleoproterozoic crust are interspersed with narrow belts displaying mantle-derived characteristics. Combined with other published data, the Nd-Sr isotopic signatures from eastern Guangdong show that the Precambrian basement in southeastern China is largely heterogeneous and made up of a series of narrow, crustal slices. The major domain boundaries coincide with large-scale NNE-trending strike-slip faults in the cover sequences. We postulate that these boundaries developed in the crust during the Mesoproterozoic and largely controlled the geological development of SE China throughout the Phanerozoic.