High-resolution X-ray microtomography and geochemical dataset of polyphase silicified gymnosperm wood from the Upper Cretaceous Valcheta Petrified Forest (Allen Formation), Patagonia, Argentina

This dataset provides the complete high-resolution X-ray micro-computed tomography (MicroCT) volume and reconstructed image stack of specimen CTES-PB 14698, a silicified gymnosperm wood (Pinales) recovered from the Upper Cretaceous Allen Formation of the Valcheta Petrified Forest, northern Patagonia, Argentina. The specimen is curated in the Dr. Rafael Herbst Palaeontological Collection (CECOAL–CONICET–UNNE, Corrientes, Argentina). The dataset comprises 1,942 reconstructed tomographic slices acquired at an isotropic voxel size of 5.002 μm using a SkyScan 1273 MicroCT system. The resulting three-dimensional volume preserves the complete internal architecture of the fossil wood and enables non-destructive investigation of anatomical organisation, pore-system geometry, mineral-density heterogeneity, and fossilisation pathways. The specimen was originally collected during fieldwork conducted in the 1970s by Dr. Pedro Maiza (Universidad Nacional del Sur) from surface exposures of the Allen Formation prior to the establishment of the present protected area. The long-term preservation and curation of this material have made possible its re-examination using modern three-dimensional imaging techniques, contributing to the documentation and scientific dissemination of the palaeontological heritage of the Valcheta region. This dataset is the primary visual component of the research presented in the manuscript: "Polyphase silicification and three-dimensional taphogeochemistry of gymnosperm wood (Pinales) from the Valcheta Petrified Forest (Upper Cretaceous Allen Formation), Patagonia, Argentina" (currently [en revision / under review / published - ajustar según el estado real]). The volumetric data supports the multiscale investigation into silicification processes, mineral-phase distribution, and taphogeochemical evolution described in the study. Integration of MicroCT observations with petrographic, spectroscopic, crystallographic, and geochemical analyses demonstrated that the specimen records a polyphasic silicification history involving transitional silica phases, residual porosity, iron-rich mineralisation, and preserved anatomical structures. The volumetric data also provide independent evidence for anatomically controlled fluid circulation during fossilisation and support palaeoenvironmental interpretations consistent with silica-rich groundwater activity in Upper Cretaceous fluvial systems. Because the acquisition was entirely non-destructive, the dataset preserves the specimen in its original curatorial state and can be reused for a broad range of applications, including palaeobotany, palaeoxylology, taphonomy, mineralogy, sedimentology, digital palaeontology, three-dimensional image analysis, machine learning, and comparative studies of fossil wood preservation. This dataset is intended to facilitate reproducibility, promote open scientific access to high-resolution palaeontological imaging data, and support future investigations into fossilisation processes and palaeoenvironmental evolution in southern Gondwanan ecosystems.