Statistical analyses of regional heavy mineral variation, Hawkesbury sandstone and Narrabeen Group (Triassic), Sydney Basin

Abstract

Abstract An analysis of variance of the available heavy mineral data from the Triassic Hawkesbury Sandstone and Narrabeen Group of the Sydney Basin shows that there is a highly significant (P < .01) difference between the two units in the average proportion of zircon and rutile where the proportion of each heavy mineral is expressed as zircon + rutile + tourmaline = 100. The analysis for the proportion of each mineral type is based on 94 samples. In addition a highly significant difference (P < .01) was observed between the two formations for size of zircon and rutile grains where grain size was recorded on 78 zircon samples, 44 rutile samples and 76 tourmaline samples. No differences could be detected for tourmaline. No other detrital heavy minerals were present in other than one or two samples and thus were of no use in differentiating the two units. The rutile in the Hawkesbury Sandstone is red and light honey brown while that in the Narrabeen Group is more commonly dark brown to almost opaque. The dif...