A CHANGE IN SEDIMENTATION PATTERNS IN A PALEOZOIC REEF REVEALED VIA THREE-DIMENSIONAL RECONSTRUCTION

Changes in Earth’s climate state can significantly impact shallow water depositional environments. One way to understand the effects of such changes is to study the meter- to kilometer-scale three-dimensional (3D) morphology of reef and reef-adjacent outcrops. Here, we present a quantitative analysis of Cambrian-Devonian strata that are well exposed along vertical cliffs at Nadaleen Mountain, Yukon, Canada. These strata, which are adjacent to the reef core, comprise platform-derived slope deposits that formed both prior to and following the Hirnantian glaciation. To visualize and describe stratal geometries, we construct a 3D digital model using UAV-derived imagery and Structure from Motion. We then project interpreted lithostratigraphic contacts—informed by field observations—onto the model, after which we calculate various morphological metrics (e.g., shape, orientation, and spatial distribution). To examine how sedimentation patterns of the reef system changed over time, we combine these reconstruction-derived insights with stratigraphic, paleontological, and geochronological data. Our analyses, which demonstrate a distinct change in depositional style, provide critical insights into how shallow water settings respond to large scale environmental change.