Serpentine minerals from two areas of the Western Australian nickel belt

MOESKOPS SUMMARY. Investigation fserpentine minerals from metaserpentinized ultramafic rocks in two Archaean green-stone belts, east of Kalgoorlie, has indicated that antigorite, xhibiting a very wide range of textures in thin section, is the dominant serpentine species; however, it is locally accompanied byrelict lizardite. Chrysotile occurs both in late tectonic veins and as a present-day weathering product of relict olivine. Analytical data and structural formulae on seven serpentines, characterized independently b X-ray diffraction analysis, upport the chemical differences between antigorite and chrysotile postulated by earlier workers. INVESTIGATIONS were restricted to serpentine minerals from the Corsair metaserpentinites, immediately east of Kalgoorlie, and the metaserpentinized Bulong (ultramafic) Complex, about 3o km east of Kalgoorlie. The interpreted geological setting of these altered ultramafic intrusives (after Williams, 1969; modified by Moeskops, 1973) is indicated in fig. 1. The Bulong Complex occurs within the regionally folded and metamorphosed acid vol-caniclastic Gindalbie Formation. Detailed work on the Complex (Moeskops, 1973; Moes-kops, in prep.) has indicated that its main concentration consists of an extensive, tightly folded, ultramafic-rich sill-zone. The structure consists of two opposite plunging synform