Major-element analysis of La Alquimia Compañía Anónima rock collection samples : a first step towards the systematic classification of Iberian karstic bauxites and kaolin deposits
Roqué Rosell, Josep (Universitat de Barcelona)
Ibañez-Insa, Jordi (Geosciences Barcelona (GEO3BCN-CSIC))
Martínez Granado, Pablo (Universitat de Barcelona)
Martín, Juan Diego (Martín Martín) (Universitat de Barcelona. Departament de Mineralogia, Petrologia i Geologia Aplicada)
Álvarez Pousa, Soledad (Geosciences Barcelona (GEO3BCN-CSIC))
Jiménez Franco, Abigail (Geosciences Barcelona (GEO3BCN-CSIC))

Fecha:	2025
Resumen:	The company La Alquimia Compañía Anónima rock collection comprises a wide range of samples from karstic bauxites to kaolin deposits across the Iberian Peninsula. Collected during mid-20th-century prospecting efforts, aimed to identify bauxites for exploitation and aluminum oxide production, this rock collection offers an unprecedented opportunity to perform a systematic study of some of the most important Iberian karstic bauxite and kaolin deposits. The major-element data from the samples were obtained through handheld X-ray fluorescence (XRF) and analyzed using Principal Components Analysis (PCA), revealing SiO2 and Al2O3 as the key components that explain the most variance. The XRF data confirmed that the samples mostly consist of karstic bauxites and kaolin, with minor amounts of gibbsite and alunite deposits. The calculated Index Of Laterization/Index Of Bauxitization (IOL/IOB) and Chemical Index of Alteration (CIA), and the SiO2 - Al2O3 - Fe2O3 and Al2O3 - CaO*+Na2O - K2O ternary diagrams have facilitated the categorization of karstic bauxites into 'bauxitic' and 'lateritic' types, and the kaolin deposits into 'gabbro' and 'granite' derived types with an intermediate to extreme degrees of weathering. The data highlights potential differences in formation settings possibly influenced by regional factors such as volcanism and tectonics, as well as global factors like eustasy and climate, which could explain the compositional disparities observed in the Iberian karstic bauxites and kaolin deposits.
Derechos:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria.
Lengua:	Anglès
Documento:	Article ; recerca ; Versió publicada
Materia:	Bauxites ; Karst ; Kaolin ; XRF ; Major-element analysis
Publicado en:	Geologica acta, Vol. 23 (2025) (Carbonate successions from Iberia and the Caribbean - Homage to Ramon Salas) , ISSN 1696-5728

Adreça original: https://revistes.ub.edu/index.php/GEOACTA/article/view/46885
Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/436836
DOI: 10.1344/GeologicaActa2025.23.8

13 p, 3.1 MB

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