Geochemical Interfacies and Taphonomy in Silicified Wood: Multi‐Analytical Evidence From the Late Pliocene Santa María Basin, Catamarca, Argentina

ABSTRACT A fossil specimen of angiosperm wood from the Corral Quemado Formation (Late Pliocene), Santa María Group, exposed at Puerta de Corral Quemado, Department of Belén, Catamarca, Argentina, was investigated. A multi‐technique analytical approach was applied to elucidate the processes of silicification and mineral alteration, reconstruct palaeoenvironmental conditions and evaluate interfacies adsorption mechanisms in palaeo‐xylological systems. X‐ray photoelectron spectroscopy (XPS), x‐ray fluorescence (XRF) and x‐ray diffraction (XRD) determined the elemental composition and mineral crystallography, while petrographic microscopy, scanning electron microscopy coupled with energy‐dispersive x‐ray spectroscopy (SEM‐EDS), and confocal Raman spectroscopy (CRS) refined the morphological and phase characterisation. The results indicate a mineral composition consistent with hydro‐geochemical fluctuations in piedmont and alluvial environments. The coexistence of iron oxides, microcrystalline silica, and traces of heavy metals reflects alternating wet and dry conditions. The integration of XPS, XRF and CRS enabled the detection of relict organic carbon, Fe 3+ and adsorption kinetics at the silica‐carbon‐iron interfaces. These findings reveal taphonomic patterns associated with silicification and the exceptional preservation of organic microstructures. This study provides new insights into the physicochemical and mineralogical mechanisms driving silicification in fossil woods, contributing to palaeoclimatic and palaeoenvironmental interpretations of the Neogene xylotaphoflora of the Santa María Basin in the Sierras Pampeanas, north‐western Argentina.