APPLICATION OF DIFFERENTIAL PIXE TO INVESTIGATE THE INTERNAL COMPOSITION OF FOSSILS

• Grant number: 25/02782-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2025
• End date: December 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Physics - Nuclear Physics
• Principal Investigator: Gabriel Ladeira Oses
• Grantee: Iago Rojahn da Silva
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 22/06485-5 - Expanding the frontiers of research in biomineralization and fossil preservation, AP.GR

Abstract

Fossils with exceptional preservation include three-dimensional specimens and with original mineralized tissues. Consequently, these fossils allow the reconstruction of phylogenetic relationships (kinship between organisms), paleoecological aspects, and paleoenvironmental conditions, thus holding great interest for different areas of research. The non-destructive (or minimally destructive) characterization of the chemical composition of mineralized tissues at different depths within the samples is essential for assessing the presence of different tissues and investigating the original composition of structures and their fossilization processes. However, this task remains a challenge, representing an ongoing analytical issue. The Crato Formation (Araripe Sedimentary Basin, Ceará) is one of the most remarkable windows into past life on the planet, consisting of the most complete fossil record of a continental paleoenvironment from the Cretaceous Period (ca. 110 million years ago). The fossil insects, fish, and plants from this formation exhibit details of both external and internal morphology. This research aims to develop a technique involving differential PIXE (Particle Induced X-ray Emission) to characterize the chemical composition of different tissues at various depths in fossils, using samples from the Crato Formation as a model. To achieve this goal, laboratory-developed standards simulating compositional contrasts of structures with different thicknesses analogous to fossils will initially be characterized by differential PIXE. Simulations will be conducted to determine specific energy values for characterizing fossils with internal composition variation profiles. (AU)