Zincian högbomite as an exploration guide to metamorphosed massive sulphide deposits

Abstract

Zincian h~gbomite (ZnO 3.5-10.5wt.%) occurs as an accessory phase in garnet quartzite that is intimately associated with the Broken Hill and Black Mountain Cu-Pb-Zn-Ag deposits, Aggeneys, South Africa. H6gbomite coexists with a number of minerals including quartz, gahnite, sillimanite, sphalerite, pyrrhotine, pyrite, magnetite, and ilmenite, suggesting that h6gbomite may have formed by sulphidation and oxidation reactions. Such reactions may account for the high Zn content of h6gbomite. Where associated with metamorphosed massive sulphide deposits h6gbomite is enriched in Zn relative to that found in ultramafics, Fe-Ti deposits, Fe ores, aluminous metasediments, and skarns. This enrichment in h6gbomite constitutes a potential exploration guide for metamorphosed massive sulphide deposits.

Zn-, Mn- and Co-rich chromian spinels from the Bou-Azzer mining district (Morocco): Constraints on their relationship with the mineralizing process

“…3A-F) and ii) the spatial relationship of chromian spinel grains, disseminated in serpentinite and included in hydrothermal arsenides and sulphides, bear out the modification of the original composition of the chromian spinel grains. Furthermore, high Zn, Mn and Co contents have never been reported in magmatic chromian spinels from barren mafic-ultramafic rocks (Groves et al, 1977;Barnes and Roeder, 2001) but are frequent in metamorphosed chromian spinels (Paraskevopoulos and Economou, 1981;Treloar et al, 1981;Spry and Scott, 1986;Spry and Petersen, 1989;Challis et al, 1995;Chattopadhyay, 1999;Barnes, 2000;Spry, 2000;Heimann et al, 2005;Barkov et al, 2009;Johan and Ohnenstetter, 2010;Singh and Singh, 2013).…”

The occurrence of h�gbomite in high-grade metamorphic rocks

“…AII hSgbomite analyses were renormalized to M2203o(OH)z assuming 8H structures. Sources of h6gbomite and spinel data: Gavelin 1917;Nel 1949;Onay 1949;Moleva and Myasnikov 1952;Kuz'min 1960;Maaskant 1970;Cech et al 1976;Karpova 1976;Woodford and Wilson 1976;Chew 1977;Wilson 1977;Zakrzewski 1977;Coolen 1981;Devaraju et al 1981;Mancktelow 1981;Gatehouse and Grey 1982;Spry 1982;Ackermand et al 1983;Marcotty 1984;Petersen 1984Petersen , 1986Spry and Petersen 1989; This paper…”

Crystal chemistry of the polysome ferrohogbomite-2N2S, a long-known but newly defined mineral species

“…Mountains, New York, formed at ca. 730°C and 7.5 kbar (1) Coolen (1981), (2) Mancktelow (1981), (3) Angus & Middleton (1985), (4) Spry & Petersen (1989), (5) Grew et al (1989), (6) and occurs associated with garnet, sillimanite, biotite, quartz, K-feldspar, magnetite, ilmenite, gahnite, corundum, rutile, pyrite, pyrrhotite, chalcopyrite, and apatite.…”

“…Associated rutile + magnetite and cordierite + corundum assemblages indicate T 500°C and P(H 2 O) < P(total) for ferrohögbomite-2N2S formation. There are various other studies on ferrohögbomite-subgroup minerals (or Fe-rich högbomite minerals) where the chemical composition has been reported (Table 2) but the type of polysome has not been determined (Coolen, 1981;Mancktelow, 1981;Angus & Middleton, 1985;Spry & Petersen, 1989;Grew et al, 1989;Razkamanana et al, 2000). A -6N12S polysome of ferrohögbomite has been chemically analysed by Nel (1949) and identified by McKie (1963).…”