Figure 1. Distribution of gem-gearing deposits (Co) related to Cainozoic basalts (enclosed areas) and deep leads (dashes) overlying basement rocks, with the Tumut Ponds serpentinite belt (filled areas). Modified from Wagga Wagga 1: 250 000 metallogenic map, showing locations of basalt sample (Nos), thin section (+) and analytical (×) sites, K-Ar basalt dates (Ma) with previous dating (O) and new dates (Z), zircon fission track dating sites (FT-Ma), zircon U/Pb isotope dating sites (U/Pb Ma), likely eruptive sites (Δ) and possible eruptive sites (Δ).