RT Journal Article T1 The Miocene Source-to-Sink Evolution of Fibrous Clay Minerals in Hyperalkaline Playa-Lakes, Duero Basin (Central Spain) A1 Del Buey Fernández, Pablo A1 Sanz Montero, María Esther A1 Rodríguez Aranda, Juan Pablo A1 Sánchez Román, Mónica A1 Nieto, Fernando AB 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. PB MDPI YR 2025 FD 2025-01-03 LK https://hdl.handle.net/20.500.14352/118179 UL https://hdl.handle.net/20.500.14352/118179 LA eng NO 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 NO Spanish Ministry of Science and Innovation NO Dutch Research Council NO Universidad Complutense de Madrid DS Docta Complutense RD 3 ago 2025