The Isotope and Trace Element Budget of the Cambrian Devil River Arc System, New Zealand: Identification of Four Source Components

The Takaka Terrane in the South Island of New Zealand containsa well-preserved Cambrian arc system (Devil River Volcanics)that displays a complete assemblage of interbedded low- to high-Karc rocks, back-arc rocks and boninites. Most volcanic rocksare mafic. A coherent dataset was obtained including major elements,trace elements and Sr–Nd–Pb isotope compositionsfrom clinopyroxene and amphibole separates. With time, ²⁰⁷Pb/²⁰⁴Pbin the arc rocks become more unradiogenic and ¹⁴³Nd/¹⁴⁴Nd moreradiogenic, and Th/Yb and La/Yb increase. La/Yb values rangefrom one in the boninites and back-arc rocks to 30 in the high-Karc rocks. Corresponding