Anion composition of apatite in the Au-Cu epithermal deposit of Palai-Islica (Almería, SE Spain) as an indicator of hydro-thermal alteration Carrillo Rosúa, Francisco Javier Esteban-Arispe, Iñaki Morales Ruano, Salvador Spain España Apatite Apatito Epithermal deposit Depósitos epitermales Hydrothermal alteration Alteración hidrotermal Mineral chemistry Química minerales The Palai-Islica deposit (Almería, SE Spain) is an Au-Cu epithermal deposit hosted in Neogene calc-alkaline andesites and dacites from the Cabo de Gata-Cartagena volcanic belt in the Betic Cordillera. Major element compositions of apatite from Palai-Islica orebody and related hydrothermally altered and unaltered volcanic rock from the region hosting the deposit were obtained to clarify the processes involved in their formation. Apatite in the host volcanic rocks is rich in chlorapatite and hydroxylapatite components (50–57% and 24–36%) and poor in fluorapatite components (12–21%), indicating assimilation processes of cortical Cl-rich material in the magmatic evolution. Apatite in the orebody sometimes has corrosion textures and is mostly fluorapatite (94–100%). Apatite from the hydrothermally altered host rock of the orebody systematically bears signs of corrosion and has variable and intermediate fluorapatite (19–100%), chlorapatite (1–50%), and hydroxylapatite (0–47%) components. The style of zonation and the composition are related to the proximity to the orebody. These features can be interpreted as the result of hydrothermal modification of high Cl, OH-rich volcanic apatites into F-rich apatites. The enrichment of F is related to the intensity of hydrothermal alteration and could therefore constitute a geochemical index of alteration and of mineralization processes. 2021-12-07T07:31:32Z 2021-12-07T07:31:32Z 2021-12 info:eu-repo/semantics/article Carrillo-Rosúa, J., Esteban-Arispe, I. & Morales-Ruano, S. (2021). Anion composition of apatite in the Au-Cu epithermal deposit of Palai-Islica (Almería, SE Spain) as an indicator of hydrothermal alteration. Minerals, 11(12), 1358. https://doi.org/10.3390/min11121358 http://hdl.handle.net/10481/71897 https://doi.org/10.3390/min11121358 eng http://creativecommons.org/licenses/by-sa/3.0/es/ info:eu-repo/semantics/openAccess Atribución-CompartirIgual 3.0 España MDPI