[1] Brown Univ, Dept Anthropol, Box 1921, Providence, RI 02912 USA
[2] Univ New South Wales, Mark Wainwright Analyt Ctr, XRF Lab, Solid State & Elemental Anal Unit, Chem Sci Bldg,F10, Kensington, NSW 2052, Australia
[3] Univ New South Wales, Mark Wainwright Analyt Ctr, Electron Microscope Unit, Chem Sci Bldg,F10, Kensington, NSW 2052, Australia
[4] UCL, Inst Archaeol, 31-34 Gordon Sq, London WC1H 0PY, England
[5] Harvard Univ, Peabody Museum Archaeol & Ethnol, 11 Divin Ave, Cambridge, MA 02138 USA