Discovery and significance of microspherules at Lower-Middle Devonian boundary of Guangxi, South China

Microspherules are found in different facies at the Lower-Middle Devonian boundary, Guangxi, South China. There are more than 20 grains per kilogram rock sample. Composition and form of the microspherules are very similar to those of the microtektites from modern deposits of South Pacific Ocean and F-F boundary (Devonian). This may indicate that the microspherules from Guangxi are most likely the products of an extraterrestrial impact event that occurred at the end of Early Devonian Epoch. The event may be responsible for the biomass reduction and extinction of benthic organisms at the end of Early Devonian. The impact products (ejecta) can be used as a potential tool for stratigraphic correlation.