2022-23 Undergraduate Research Project by Samantha Zink, supervised by Madeline S. Marshall (paleontologist) and Shauna Merriman (sculptor)
Demosponge body fossil reconstructionsSpicule (microfossil) reconstructions
GSA Connects 2022 Abstract excerpt: Glass ramps and ceramic sponges: sculpturally reconstructing taphonomic patterns of Permian demosponges in the Phosphoria Rock Complex, Idaho
Samantha Zink and Madeline S. Marshall, Albion College The Permian Phosphoria Rock Complex (PRC) of Idaho is a widespread sedimentary deposit that accumulated in a shallow sea along the western margin of Pangea. The Rex Chert Member of the PRC records an interval of atypical ocean conditions that favored biosiliceous sedimentation, a glass ramp populated by sponge meadows and starved of siliciclastics. The Rex Chert is up to 30 m thick, and is composed of the disaggregated spicules of siliceous demosponges. Few intact specimens of PRC sponges are preserved, presenting challenges in reconstructing their forms in life. This study utilizes an interdisciplinary approach to model assemblages and morphologies of PRC demosponges, combining limited fossil data with modern demosponge data to inform artistic fabrication of models of whole PRC sponges. The silicified preservational style necessitates a conceptual reversal of the taphonomic processes that fossilized these sponges to reconstruct the paleoenvironments from their remains. Fabrication of sponge sculptures is key to reconstructing this non-analogue paleoenvironment, including filling in features that are lost to time, such as color. The silicified matrix and sponge fossils within obscures many morphological details; however, combining macro- and microscale taphonomic data with experimentation of form allows for the development of a more complete model.
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