In this paper, LA-ICP-MS zircons with U-Pb ages of 1723~1736 Ma are reported for the first time in the Paleoproterozoic （metamorphic）rhyolite ignimbrite in the Ibitiara-Rio de Contas area of the S?o Francisco Craton Bahia State, Central and eastern Brazil. The geochemical characteristics of these rocks are high in silicon, aluminum and alkali components, and significantly poor in calcium and magnesium. The enriched large ion lithophile elements (such as K, Th, U, Rb, Ba, Sr) and the relatively deficient high field strength elements (such as Nb, P, Zr, Hf) and Ti were obviously deficient. The rare earth element abundance value is high (∑REE is (317.22×10-6-829.54×10-6), light rare earth elements are relatively enriched（(La/Yb)N为3.26~6.57.The rare earth partition curve showed a slight right-leaning, strong negative Eu anomaly（δEu = 0.05~0.42）of seagull type. The volcanic zircon Ti thermometer shows that the magma temperature is 706~943℃, and the saturation temperature of zircon is 836~992℃. These characteristics indicate that the volcanic magma in this area has the characteristics of high temperature and shallow achievement, which is calc-alkaline aluminum A-type granite, formed in the environment of non-orogenic intracontinental plate rift zone. The volcanic magma has undergone crust and mantle partial melting and crystallization differentiation, and a trend of silica rich evolution from the volcanic rock from the west to east.