THE PERMIAN-TRIASSIC TIME SLICE PROJECT OF CHRONOS: A REFINED CHRONOSTRATIGRAPHIC FRAMEWORK TO ANALYZE EXTINCTION AND RECOVERY

Development of a high-resolution, integrated global chronostratigraphic framework will resolve the sequence of events, thereby constraining the causes of the catastrophic late-Permian extinctions and early-Triassic recovery. The Permian-Triassic Time Slice Project spans a 20-million-year interval from the base of the Jinogonodolella postserrata conodont zone (Capitanian, Middle Permian, ~265 Ma), to the base of the Neospathodus waageni conodont zone (early Smithian, Early Triassic, ~245 Ma). The Project is a CHRONOS Beta-test of how to code, access and integrate different types of stratigraphic data to address a major earth history event. The main emphases of the Project are to encourage active international sharing of data and expertise, experiment with the most effective methods of coding information in different disciplines, from different stratigraphic methods, and develop methods to apply visualization and analysis tools to the composite datasets. Each stratigraphic method, especially conodont biostratigraphy, require standardization to achieve consistent correlations. To this end, a taxonomic dictionary was developed (available at http://www.PaleoStrat.com) with reference citation, original taxonomy, digital image library and open synonymy that include all the published figured specimens and original descriptions. In addition, digital images of over 1,000 unpublished specimens from Iran, Pakistan and China were incorporated. In the first round of the open synonymy, the Changxing Limestone at Meishan, China, previously divided into 2-3 conodont zones, now can be divided into 6 well-defined zones based on the redefined Clarkina species. Correlation to other sections and other fossil groups (such as radiolaria) is also strengthened.