Mineralogical characterization of fossil woods from the Las Cañas Formation (early Pliocene), Santiago del Estero, Argentina, mainly using SEM and EDX, XRD, FTIR and Confocal Raman spectroscopy

Abstract

This study conducted physicochemical and mineralogical characterization of fossil angiosperm woods, from Neogene fluvial sedimentary deposits of the Dulce River (Termas de Río Hondo Sector), Santiago del Estero Province, Argentina. Chemical and instrumental analyses demonstrated that the early Pliocene specimens comprise extensively mineralized silica polymorphs. In this work, X-ray diffraction (XRD) techniques combined with scanning electron microscopy (SEM) with backscattered electron detector (BSE) and spectroscopic techniques such as energy dispersive X-ray (EDX), confocal Raman (CRS) and Fourier transform infrared (FTIR) were applied. This research includes not only the physicochemical characterization of angiospermic logs, especially the indeterminate species of Vitaceae (Vitaceoxylon sp.) and Menendoxylon mesopotamiensis, but also studies the analysis of the regional geological environment that allows paleoenvironmental, paleoclimatic and paleobiogeographic inferences for the neogenic xylotaphoflora related to the outcrops of the Dulce River, in the transition between the Pampean Sierras of the Northwest (NW) and the basin of the Chaco-Pampean Plain, Argentina.