Paleozoic cherts from the Mianlue and the Erlangping ophiolite zones of the Qinling orogenic belt are characterized by low Si/Al ratios (52.14-683.52 in the Mianlue cherts, 12.29-58.62 in the Erlangping cherts), Fe2O3 (0.01 -0.35 and 0.02-1.24) and high Al2O3/(Al2O3+Fe2O3)ratios (0.82-0.99 and 0.83-0.99). The negative correlation between Si2O and AI2O3 in the cherts reflects the important role of terrigenous components. The Erlangping cherts have Lar/Cen=0.9-1.15 and Ce/Ce*=0.95-1.15 with low contents of V, Ni and Cu, consistent with those of cherts forming on the continental margin. In contrast, the Ce/Ce* ratios of the Mianlue cherts range from 0.71 to 1.18 and Lan/Cen from 0.88 to 1.43 with slightly high V, Ni and Cu,which are similar to cherts found in the mid-ocean ridges and pelagic basins. Combined with the features of basic lavas associated with the cherts, it is suggested that during the Paleozoic, when the back-arc basin represented by the Erlangping ophiolite commenced shrinking in size in the mid-Ordovician, the southern Qinling was still in an extensional regime and finally grew into a new limited oceanic basin in the early Carboniferous.