The full recovery from the end Permian extinction event had a duration of about 6 Ma delayed Early Triassic recovery was longer than could be accounted for merely by the magnitude of the extinction and was best explained by continuing environmental stress. Crucial to models for the extinction and subsequent recovery is a precise chronology. A volcanic ash horizon was found under the Luoping biota (Anisian) layer. It is widely distributed in southern China and named the green bean rock. Zircon LA ICP MS U Pb age of 246.6±1.4Ma provides limit to the age of Luoping biota. It provides a precise point time for recovery and radiation, and provides a time frame for regional stratigraphic correlation.