Abstract: Located at easternmost part of the Early Paleozoic tectono-magmatic belt of the Chaganobo-Aououte-Chaobuleng along the southern edge of the Siberian plate, the newly discovered Arehada deposit is a largescale Pb-Zn deposit occurring in the centraleastern Inner Mongolian Autonomous Region.We present 20 new sulfur and lead isotope data of wall rock and orebodies. The sulfur isotope compositions of wall rock are similar to those of orebodies. The δ³⁴S values vary from 1.2‰ to 8.6‰. The sulfur isotope compositions show different sources. The temperatures calculated from sulfideparas show high temperature stage and medium low temperatrue stage. The ²⁰⁶Pb/²⁰⁴Pb,²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios of 17 sulfide samples of orebodies vary in ranges of 18.153-18.431, 15.370-15.602 and 37.653-38.213,with the average values of 18.271,15.464 and 37.873,respectivly. The ²⁰⁶Pb/²⁰⁴Pb,²⁰⁷Pb/²⁰⁴Pb and ²⁰⁸Pb/²⁰⁴Pb ratios of 3 sulfide samples of wall rock vary in ranges of 18.281-18.293,15.470-15.484 and 37.874-37.909,with the average values of 18.288,15.477 and 37.893, respectively. The lead isotope compositions are similar to those of biotite granite and metasandstone from Chaobuleng skarn ironpolymetallic deposit. It indicates that the sources of lead is wall rock and Indosinian granite.

Key words: sulfur and lead isotope, Pb-Zn-Ag deposit, genesis, Arehada, Inner Mongolia