34 Paleontology

Wednesday, 11 March 2026
8:30 AM - 10:00 AM
RCC, 103

New Discoveries from Baltica’s Blue Clays: The Survival of Estonia’s Cloudinomorphs

Paper number: 34-4
Program: Technical Sessions
Time: 9:30 AM – 9:45 AM

Authors

Abstract

Amongst fossils from the early Cambrian (Terreneuvian Series) blue clays of Estonia are cloudinomorphs, tube-building organisms that have long been thought to have gone extinct at the Ediacaran-Cambrian boundary. These fossils, along with similar discoveries from South China and older reports from Russia and Spain, challenge long-held assumptions about the evolutionary transition across the Ediacaran–Cambrian boundary (~539 Ma). The persistence of cloudinomorphs into the early Cambrian suggests a much more complicated ecological transition across the Ediacaran-Cambrian boundary than previously recognized. To refine our understanding of this pivotal transition period, we have examined the structure, preservation, and ecology of these blue clay cloudinomorph fossils.

          We have begun to unravel the taxonomic and taphonomic details of these fossils using advanced imaging techniques, including high-resolution X-ray tomographic microscopy (µCT) and scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS). Three distinct preservation modes have been identified, with both three-dimensional and compressed forms. We have, through µCT, discovered a high morphological diversity that exceeds expectations and discovered previously undetected fibrous structures that vary in density throughout the samples. EDS analyses offer new insights into the burial environment and taphonomic history of these fossils, reframing the initial interpretation of a shallow sea environment through fossil-associated mineral phases including gypsum, barite, and halite.

          Through the integration of multiple advanced imaging techniques, our study aims to resolve taxonomic and taphonomic uncertainties regarding the Baltic Basin at this critical time in evolutionary history. These findings provide evidence of resilience within communities at a time of dramatic ecological change and provide a new perspective on the survival of Cloudinimorphs through the Ediacaran-Cambrian transition. These fossils contribute to our understanding and modeling of ecological resilience and the terminal Ediacaran extinction.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411563

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