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oai:docta.ucm.es:20.500.14352/1181792025-03-11T08:54:55Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc Del Buey Fernández, Pablo author Sanz Montero, María Esther author Rodríguez Aranda, Juan Pablo author Sánchez Román, Mónica author Nieto, Fernando author 2025-01-03 Palygorskite is assumed to be the predominant clay mineral in playa-lakes, where it may be detrital or authigenic in origin. Discriminating between detrital and authigenic clays is crucial to elucidate paleoenvironmental conditions in lacustrine deposits. This study provides insight into the sedimentary evolution of clay minerals from source, lacustrine Miocene marlstones and mudstones, to sink, represented by three recent hyperalkaline playa-lakes in Central Spain. XRD, TEM, and AEM analyses show concomitant detrital and authigenic palygorskites in the three playa-lakes. The inherited palygorskites exhibit degradation features, larger widths, and common and ideal compositions, in contrast to neoformed particles. The latter are narrower. Depending on the hydrochemical composition of each playa-lake, neoformed palygorskites are enriched in a different octahedral cation (Al2O3, MgO, and Fe2O3). Iron-rich palygorskites are only formed in association with authigenic saponites in one of the playa-lakes. The same effect of magnesium competition between smectite and palygorskite is observed in Miocene mudstones, where palygorskite is relatively enriched in iron. In hyperalkaline, seasonal playa-lakes lying in the vicinity, slight physicochemical differences play a crucial role in the crystallochemical composition of authigenic palygorskites, highlighting the use of this mineral as a geochemical proxy. del Buey, P.; Sanz-Montero, M.E.; Rodríguez-Aranda, J.P.; Sánchez-Román, M.; Nieto, F. The Miocene Source-to-Sink Evolution of Fibrous Clay Minerals in Hyperalkaline Playa-Lakes, Duero Basin (Central Spain). Minerals 2025, 15, 50. https://doi.org/10.3390/min15010050 10.3390/min15010050 https://hdl.handle.net/20.500.14352/118179 2075-163X https://doi.org/10.3390/min15010050 https://www.mdpi.com/2075-163X/15/1/50 The Miocene Source-to-Sink Evolution of Fibrous Clay Minerals in Hyperalkaline Playa-Lakes, Duero Basin (Central Spain)