Date of Award


Degree Type


Degree Name

Master of Science in Biological and Environmental Sciences (MSBES)


Environmental and Earth Sciences (EVES)



First Advisor

David E. Fastovsky


In the Late Triassic of Petrified Forest National Park (PEFO), AZ, the coincidence of high-precision geochronology and robust lithostratigraphy allows an adaption of the Bayesian statistical approaches of Haslett and Parnell (2008) and Alroy (2014) to quantify the dynamics of a Late Triassic vertebrate extinction and replacement, the Adamanian-Revueltian (A-R) faunal turnover. This analysis indicates negligible probability of synchroneity of Adamanian extinctions and Revueltian originations. This protracted reconstruction of the A-R turnover decouples the event from the geologically instantaneous Manicouagan impact (215.4 + 0.20 Ma; Québec, Canada), previously implicated as a causal mechanism.



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