ANIMAL ABUNDANCE AND CHANGING REDOX CONDITIONS DURING THE FURONGIAN CAMBRIAN SPICE EVENT, WESTERN UTAH

The Steptoean Positive Isotopic Carbon Excursion (SPICE) has been documented in late Cambrian stratigraphic sections worldwide. The onset of the SPICE aligns with a global extinction event of trilobites, marking the Marjumiid-Pterocephaliid biomere boundary. Although the cause of both the excursion and the extinction event are debated, multiple lines of evidence suggest changes in ocean redox conditions may have been responsible. The House Range and Lawson Cove sections in western Utah are two of the localities where the SPICE event was first reported. These sections are comparatively fossiliferous among units recording the SPICE event. Here, we report new geochemical and fossil data from strata that span the SPICE event at both localities. We use geochemical redox proxies to better understand the timing of local environmental change during the SPICE. We report skeletal abundance and diversity through both sections to ascertain how the SPICE event and concurrent environmental changes influenced marine organisms. By coupling evidence for environmental change with animal abundance and diversity, we hope to better constrain one of the best known yet still poorly understood carbon isotopic excursions of the Cambrian.