Table 3 in The Tumbarumba Basaltic Gem Field, New South Wales: In Relation to Sapphire-Ruby Deposits of Eastern Australia

Table 3. Zircon fission track results, Tumbarumba-Cabramurra area. number of grainsNsNiNaratioRHOsRHOi age (Ma) ± errorU ppm (av.)Parsons Gully, Buddong Creek (sub-basaltic lead)dark red grains: 42835341000.5253.23E+066.09E+0626.0±1.1149–505 (av. 290)Tumbarumba Creek, Miller’s property (sub-basaltic lead)dark red grains: 8154215690.7603.533E+064.933E+0622.8±1.095–819 (av. 361)pale grains: 8237312770.7704.902E+066.439E+0623.6±0.9153–1433 (av. 486)bright polished grains: 952831000.6108.193E+051.322E+0618.6±1.237–161 (av. 103) Determinations from Geotrack Reports No. 30 (Buddong Creek, compiled by P.F. Green & I.R. Duddy, 1985) and No. 655 (Tumbarumba Creek, compiled by P.F. Green, 1997). Standard (RHOD) and induced track RHOi densities were measured on external detector faces and fossil track densities (RHOs) on internal mineral surfaces. Ages were calculated using a Zeta of 87.9 (Buddong Creek) and 87.7±0.8 (Tumbarumba Creek) for dosimeter glass U3. Ns is the number of spontaneous tracks, Ni the number of induced tracks and Na area of units of counted tracks. RHOD (cm –2) is 1.119E+06 (Buddong Creek) and 6.858E+05 (Tumbarumba Creek). Ages represent pooled ages and errors are quoted as ±1.