Table 1

SHRIMP U/Pb zircon analyses

  • all uncertainties in table are given at 1 sigma.

  • site x.y; x=grain number, y=analysis number.

  • grain character: p=prism, stubby=small aspect ratio prism, anh=anhedral, ov=oval, eq=equant, bip=bipyramidal, f=grain fragment

  • site of analysis: e=end, m=middle, r=rim, c=core

  • analysis site in CL image: osc=oscillatory finescale zoning, sz=sector zoning, h=homogeneous, hd=homogeneous and dull, hb=homogeneous and bright, comp=composite domain

  • descriptions in italics indicate post-analysis CL-imaging

  • comm 206%= percentage of Pb that is non-radiogenic, based on measured 204Pb and common Pb modeled as 2700 Ma (in Archean rocks) and (1900 Ma in Proterozoic rocks) of Cumming and Richards (1975)