Textural and chemical features of sphalerite from the Palai-Islica deposit (SE Spain): implications for ore genesis and color
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E Schweizerbart Science Publishers
SphaleriteEpithermal depositSpainSbSnColorChalcopyrite diseaseCathodoluminescenceEsfaleritaCatodoluminiscencia
Carrillo-Rosúa, J.; Morales-Ruano, S.; Fenoll Hach-Alí, P. Textural and chemical features of sphalerite from the Palai-Islica deposit (SE Spain): Implications for ore genesis and color. Neues Jahrbuch Fur Mineralogie, Abhandlungen, 185(1): 63-78 (2008). [http://hdl.handle.net/10481/35402]
PatrocinadorThis work has been supported by the Spanish projects CGL-2006-02594/BTE (Ministry of Education and Science and FEDER), and RNM-732 (Junta de Andalucía). J. Carrillo-Rosúa thanks postdoctoral grant from MEC for his support. Authors are very grateful to Fernando de la Fuente Consultores S.L. for providing drill cores samples and for his help during field work. The manuscript was significantly improved by helpful suggestions and critiques by Prof. Gene C. Ulmer.
Sphalerite in the Au-Cu volcanic-hosted, Palai-Islica deposit appears in three locations with differences in chemistry, mainly in the Fe content: a) included in pyrite (Fe: 0.49 – 5.47 at. %) within the quartz veins; b) disseminated or in crustiform bands, also within the quartz veins; and c) disseminated in hydrothermally altered volcanic rocks from the deepest part of the deposit (Fe: 0.28 – 1.12 at. % - the only one which is cathodoluminescent). Disseminated- or crustifom band-sphalerite is the most abundant type, with two varieties: dark (Fe: 3.16 – 8.66 at. %) and light (Fe: 0.08 – 2.52 at. %). The former is associated with zones rich in gold and other metals. The Fe content of sphalerite reflects an evolution in fs2 of the hydrothermal fluids. Fe-rich, “dark” sphalerite could be related to a mixing process triggering noble- and base metal sulphide precipitation. Different types of sphalerite have significant amounts of minor elements, such as Cu (up to 1.34 at. %), Sb (up to 0.67 at. %), Sn (up to 0.31 at. %), Ge (up to 0.29 at. %), Cd (up to 0.24 at. %), In (up to 0.18 at. %), Mn (up to 0.15 at. %) and Ga (up to 0.12 at. %), some of which are elements not traditionally recognized in sphalerite. Among them, Sb, Sn, Ga-Ge and In are proportional to Cu content, and the following charge balanced coupling substitutions have been demonstrated: Sb3+ + Cu+ + Cu 2+ 3Zn2+; Sn4+ + 2Cu+ 3Zn2+; 2Ge2+ + Ga3+ + 2Cu2+ + Cu+ 6Zn2+. The first two substitutions have been shown to correlate with red coloration in Fe-poor sphalerite. The latter substitution, could be related to incorporation into the hydrothermal system of Ga-Ge bearing fluids from the basin. The presence of cathodoluminescent sphalerite seems interesting since it could reflect distinctive trace element content, and could help to distinguish a different type of mineralization and fluid/metal source manifested in an unexplored part of the deposit.