FIRST FINDING OF NATIVE GOLD IN CHROMITES FROM ROCK MASSIFS OF KRAKA (SOUTHERN URALS)

Abstract

Rare findings of native gold in ultramafic rocks provide insight into specific features of their genesis or transformation. Findings of native gold spherules (5–30 μm across) in olivine, pyrrhotite, and magnetite grains were reported from ultrabasic rocks of the Loveld deposit (South Africa). In the Urals, Pd-bearing native gold with high contents of Cu and Hg was found in metamorphosed chromites of stratiform complexes and in olivine–antigorite rocks of the Syum–Keus Massif. In ultramafic rock massifs of Kraka, native gold was discovered during the mineragraphic study of rock samples taken above the ore zone of the Bol’shoi Bashart deposit (Yuzhnyi Kraka Massif). The native gold was represented by tiny (from n μm to 0.08 × 0.01 mm) irregular segregations confined to thin cracks in chromites. Native gold particles of similar size (0.05 × 0.1 mm) were detected in panning samples of the ore-hosting ultramafic rocks of the Khamitov deposit and the Sarangaev ore occurrence located in the banded complex of the Srednii Kraka Massif.