ARCHAEOCYATHID REEFS AS FACILITATORS OF BIODIVERSITY IN THE LOWER CAMBRIAN

The major pulses of animal originations during the Lower Cambrian coincide with the rise of Earth's first animal-built framework reefs. Given the importance of Scleractinian coral reefs as facilitators of biodiversity in modern oceans, we are investigating Archaeocyathid reefs as potential drivers of the Cambrian Explosion of animal biodiversity. In this study, we present a multi-faceted approach for the reconstruction of Archaeocyathid reefs as a paleoenvironment with a special interest in their ability to facilitate animal diversication through habitat engineering. Working at field sites in Nevada and Yukon Territories, Canada, we use drone-derived imagery and dGPS-constrained observations to map and sample reefs in high-resolution, three-dimensional (3D) geospatial frameworks--complemented by a fourth dimension; stratigraphic time. Within this mapping framework, we perform quantitative image analysis of hundreds of thin sections from both sites to understand the balance of extrinsic vs. intrinsic environmental forcings, as well as their variation in space and time.

Further, we leverage machine learning techniques to segment the thin section images to quantify the relative abundance and diversity of associated fauna at each sampled point within the reefs. At points of interest identied in thin section study, we produce 3D renderings of reef volumes through serial grinding and imaging. Analysis of these volume renderings constrains the potential for Archaeocyathid reefs to facilitate diversication in associated fauna by increasing synoptic relief in shallow tropical seas and providing novel environment types such as primary vug space. Additionally, through 3D renderings we have identied and measured never-before-seen dense branching networks of Archaeocyathids, quantifying their ability to build structural frameworks rising above the seaoor, housing an abundant and diverse associated fauna. Analyzing environmental metrics, 3D structure, and faunal diversity in concert, we are able to correlate spatial and temporal patterns of biodiversity with the environments built by Archaeocyathids.