Journal article

ISOTOPIC AND TRACE-ELEMENT PROFILES ACROSS THE NEW-BRITAIN ISLAND-ARC, PAPUA-NEW-GUINEA

JD WOODHEAD, RW JOHNSON

CONTRIBUTIONS TO MINERALOGY AND PETROLOGY | SPRINGER VERLAG | Published : 1993

Abstract

New Pb-, Sr-, and Nd-isotopic data have been obtained for the rocks of volcanoes overlying a wide range of depths (100-580 km) to the Wadati-Benioff Zone (WBZ) in the New Britain island arc, Papua New Guinea. Well-defined trends consistent with two-component mixing are observed in combined Pb-isotope/trace-element plots. One of the components is believed to represent a slab contribution whose isotopic signature, unlike those noted for several other arcs, appears to be dominated by subducted, altered, oceanic crust rather than by sediment. This conclusion is consistent with the results of a recent Be-B study of New Britain rocks. The influence of the slab component is considered to decrease a..

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