Contributions to Mineralogy and Petrology

, Volume 113, Issue 4, pp 479–491

Isotopic and trace-element profiles across the New Britain island arc, Papua New Guinea

  • Jon D. Woodhead
  • R. W. Johnson
Article

DOI: 10.1007/BF00698317

Cite this article as:
Woodhead, J.D. & Johnson, R.W. Contr. Mineral. and Petrol. (1993) 113: 479. doi:10.1007/BF00698317

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 as depth to the WBZ increases. Higher abundances of high-field-strength elements correlate with increasing depths to the WBZ, and may be indicative of smaller degrees of partial melting of the mantle wedge as WBZ depths increase. Abundances of other incompatible elements appear to reflect a complex interplay between the slab-derived flux and melting process.

Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • Jon D. Woodhead
    • 1
  • R. W. Johnson
    • 2
  1. 1.Research School of Earth SciencesAustralian National UniversityCanberraAustralia
  2. 2.Australian Geological Survey OrganisationCanberraAustralia