Significance of phyllosilicate mineralogy and mineral chemistry in an epithermal environment. Insights from the Palai-Islica Au-Cu deposit (Almería, SE Spain)
Carrillo-Rosúa, Javier (Universidad de Granada. Departamento de Didáctica de las Ciencias Experimentales)
Morales-Ruano, Salvador (Instituto Andaluz de Ciencias de la Tierra)
Esteban-Arispe, Iñaki (Universidad de Granada. Departamento de Mineralogía y Petrología)
Hach-Alí, Purificación Fenoll (Instituto Andaluz de Ciencias de la Tierra)

Fecha:	2009
Resumen:	Phyllosilicate mineralogy is key to understanding hydrothermal processes within accepted epithermal deposit models but little information has been published about the mineral chemistry of epithermal deposits. X-ray diffraction, optical and electronic microscopy (scanning and transmitted), electron microprobe, and Fourier transform infrared spectroscopy were used in this work to study phyllosilicates in the Palai-Islica Au-Cu epithermal, volcanic-hosted deposit, in order to link phyllosilicate mineralogy and mineral chemistry to ore genesis. Different phyllosilicate assemblages are characteristic of two types of mineralization, and related hydrothermal alteration. Chlorite and mica appear in polymetallic quartz veins with sulfides, and in the related chloritic and sericitic hydrothermal alteration. These minerals have notable textural and chemical differences (i. e. Fe/(Fe+Mg), Si and Al in chlorite and illitic and phengitic components in mica) amongst veins and altered rocks, revealing different genetic conditions. These chemical features also distinguish propylitic and regional, non ore-related, low-temperature alteration. Hot hydrothermal fluids of near-neutral pH are responsible for vein mineralization and alteration. Illite, interstratified illite-smectite, kaolinite, and pyrophyllite are characteristic, with a distribution pattern by zones, of the intermediate argillic and advanced argillic alteration around areas of silicification. In the latter, native gold appears associated with interstratified illite-smectite, suggesting a relatively low-temperature formation. Hot, low-pH fluids are responsible for this mineralization and alteration assemblage. The present study contributes to epithermal models showing the co-existence of two different alteration styles in the same hydrothermal system.
Ayudas:	Ministerio de Educación y Ciencia CGL2006-02594
Nota:	Altres ajuts: Junta de Andalucía (RNM-732)
Derechos:	Tots els drets reservats.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	Chlorite ; Epithermal ; Gold ; Mica ; Spain ; Intermediate-sulfidation ; Volcanic-hosted
Publicado en:	Clays and Clay Minerals, Vol. 57, Núm. 1 (2009) , p. 1-24, ISSN 1552-8367

DOI: 10.1346/CCMN.2009.0570101

24 p, 6.8 MB  Acceso restringido a la UAB

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