Boyang Xia, Huaichun Wu, Quanguo Li
One of the richest known fossil records of penguins occurs in the Eocene La Meseta and Submeseta formations on Seymour Island, Antarctic Peninsula. These fossils provide a unique window into penguin evolution and associated Antarctic paleoclimate transitions. In this study, µ-XRF mapping was used to analyze high-resolution elemental distributions in penguin bones spanning the early to late Eocene, together with extant comparative specimens. The influence of depositional environments and climatic events on elemental enrichment patterns during fossilization was assessed. The results show that early Eocene fossils (55.3–54.1 Ma) preserve markedly elevated Tiµ-XRF signal intensities, which are consistent with increased weathering-derived terrestrial input under warm and humid climatic conditions when considered together with sedimentological and paleoclimatic evidence. Furthermore, the elemental enrichment patterns in the fossils likely reflect multiple processes, including infiltration, silicification, incorporation of fine-grained detrital material, and redox-controlled mineralization. Integration of these µ-XRF data with the sedimentological context and paleotemperature records suggests that elemental differentiation among fossils reflects stratigraphically coherent variations in weathering intensity, depositional energy, and redox conditions during the Eocene greenhouse–coolhouse transition. This study is the first to reveal patterns of elemental variation across a sedimentary sequence using vertebrate fossils, offering a novel link between vertebrate fossil geochemistry and paleoenvironmental change on the Antarctic Peninsula.