DOCUMENTING REGIONAL BRACHIOPOD ABUNDANCE AND DIVERSITY ACROSS THE MISSISSIPPIAN-PENNSYLVANIAN BOUNDARY: BIRD SPRING FORMATION, ARROW CANYON, NEVADA

We presently are living through the “modern biodiversity crisis” caused by climate change. Examining past taxonomic patterns across major environmental perturbation provides a much needed perspective on how biotas might respond to future climate transitions. During the middle Carboniferous, a global climate transition from warmer greenhouse conditions to cooler icehouse conditions took place at the Mississippian-Pennsylvanian boundary. Many paleocommunities reorganized at this transition causing a second order mass extinction. The purpose of this research is to document the faunal patterns before and after the boundary interval. The Shannon Diversity Index was used to determine the alpha diversity within the samples to measure the taxonomic richness, and rank-abundance curves (RAC) were used to assess the ecological response of organism across the boundary. We found that the global climate change associated with the Mississippian-Pennsylvanian boundary interval forced marine fauna to reorganize locally, causing a drop in diversity and a change in dominant taxa through time.