189-1 Low-cost photoluminescence approaches for large paleontological samples

Session: Paleontology, Paleoecology/Taphonomy (Posters)

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Abstract:

Photoluminescence is the emission of light following photon excitation. This phenomenon is widely used in modern biological imaging, especially at the microscopic scale, but remains underutilized in paleontology and geology, especially for relatively large fossils. In this study, we evaluate two accessible, low-cost photoluminescence methods for enhancing fossil visualization and assess their strengths and limitations. The first method employs bright LED arrays with UVA, blue (450-460 nm), and green (520-536 nm) excitation sources, used in combination with long-pass filters to isolate luminescent emissions. The second uses high-power 405 nm and 450 nm line lasers to scan samples, coupled with dichroic filters to manage high photon flux. In both approaches, captured images can be eventually processed into grayscale and composited into false-colored photoluminescence maps (i.e., multispectral imaging). Both LED and laser-based techniques revealed significantly improved contrast in fossils with heterogeneous mineralogy. Enhanced imaging allowed us to resolve compositional variations and fine structural details otherwise obscured under white light. For example, imaging of a complete Confuciusornis specimen revealed preserved soft tissues and phosphatized structures, including skin and claws. Similarly, a marine decapod fossil in limestone showed dramatically improved definition compared to conventional lighting. Other examples, encompassing trilobites, rugose corals, Ediacaran biomineralized taxa, and Cenozoic plants, all demonstrated varied photoluminescence responses, reflecting differences in composition and diagenetic mineral phases. In contrast, most fossils with only carbonaceous compounds yielded minimal enhancement, with exceptions such as Spongiophyton, a remarkably preserved Devonian early lichen, which fluoresced distinctly. Both LED and laser approaches performed similarly for small-to-medium fields of view (millimeters to a few centimeters), but only laser scanning proved effective for larger specimens. Photoluminescence is sensitive to trace element content, crystal structure, and defects, which are factors often shaped by diagenesis. When combined with appropriate filters, both laser and LED-based imaging offer a powerful and cost-effective toolset for revealing hidden morphological and chemical fossil features. This approach holds particular promise for macrofossil studies where traditional techniques may fall short.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-8067

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