Application of graphic correlation to compare Lower Permian sections of the Glass Mountains, West Texas and the western slope of the Ural Mountains, Russia

An Artinskian-Kungirian Global Boundary Stratotype Section and Point (GSSP) has been proposed for two stratigraphic intervals: the Artinskian through Kungurian stages of the western slope of the Ural Mountains, Russia, and th e Leonardian Series of the Glass Mountains, West Texas. Graphic correlation applied separately to each of these intervals produced a viable composite section for the Glass Mountains Leonardian succession, whereas a composite section for the Artinskian-Kungurian succession could not be constructed wi thin an acceptable level of confidence. In graphic correlation, selection o f a standard reference section (SRS), which acts as the starting point for all succeeding graphic correlations, is an essential first step. Therefore, because the requirements for a global boundary stratotype section are esse ntially the same as the requirements for a SRS, it is concluded that the Ar tinskian-Kungirian GSSP should be established in a Leonardian section of th e Glass Mountains rather than in a section from the Artinskian-Kungurian in terval of the Ural Mountains.