Mineralogy and geochemistry of claystones from the Guadalupian–Lopingian boundary at Penglaitan, South China: Insights into the pre-Lopingian geological events

The Guadalupian–Lopingian (G/L) boundary, at a stratigraphically well-documented outcrop in Penglaitan, Guangxi Autonomous Region, South China, has been approved as the Global Stratotype Section and Point (GSSP). Several volcanic ashes or tuffs occur at this boundary, but their mineralogy and geochemistry are not available yet and no reliable age for this boundary has been obtained. A combined study of mineralogy, geochemistry and geochronology...