The species radiation occurred in the interval from the middle–late Drumian to middle Guzhangian. The extinction began in the middle of Guzhangian and lasted 3 million years until the middle of the Paibian age. As a result of this extinction, species diversity was reduced by 45%. Two phases of extinction can be traced in the sediments of South China: the first, with a slight decline in species, lasted about 1.8 million years; the second, with a sharper decline in richness, lasted 1.2 million years, more in the Paibian. After the extinction, species diversity returned to its previous level. From the Guzhangian to
Jiangshanian, the oceans experienced a gradual depletion of oxygen, which affected bottom-dwelling inhabitants. This process and the
SPICE event, associated with it, likely became the cause of the extinction. ==References==