The Khondalite Belt within the Inner Mongolia Suture Zone(IMSZ) in the North China Craton is a classic example for Paleoproterozoic ultrahigh-temperature(UHT) metamorphism.Here we report new spinel-bearing metapelitic granulites from a new locality at Xumayao within the southern domain of the IMSZ.Petrological studies and thermodynamic modeling of the spinel+quartz-bearing assemblage shows that these rocks experienced extreme metamorphism at UHT conditions.Spinel occurs in two textural settings:(1) high X_(Zn)(Zn/(Mg+Fe~Ⅱ+Zn)=0.071-0.232) spinel with perthitic K-feld-spar. sillimanite and quartz in the rock matrix;and(2) low X_(Zn)(0.045—0.070) spinel as inclusions within garnet porphyroblasts in association with quartz and sillimanite. Our phase equilibria modeling indicates two main stages during the metamorphic evolution of these rocks:(1) near-isobaric cooling from 975℃to 875℃around 8 kbar.represented by the formation of garnet porphyroblasts from spinel and quartz;and(2)cooling and decompression from 850℃.8 kbar to below 750℃.6.5 kbar,represented by the break-down of garnet.The spinel+quartz assemblage is considered to have been stable at peak metamorphisni.formed through the break-down of cordierite.indicating a near isothermal compression process.Our study confirms the regional extent of UHT metamorphisni within the IMSZ associated with the Paleoproterozoic subduction-collision process. The Khondalite Belt within the Inner Mongolia Suture Zone (IMSZ) in the North China Craton is a classic example for Paleoproterozoic ultrahigh-temperature (UHT) metamorphism. Here we report new spinel-bearing metapelitic granulites from a new locality at Xumayao within the southern domain of the IMSZ. Petrological studies and thermodynamic modeling of the spinel + quartz-bearing assemblage that those rocks of extreme metamorphism at UHT conditions. Spinel occurs in two textural settings: (1) high X - (Zn) (Zn / (Mg + Fe ~ (Zn) = 0.071-0.232) spinel with perthitic K-feld-spar. Sillimanite and quartz in the rock matrix; and quartz and sillimanite. Our phase equilibria modeling shows two main stages during the metamorphic evolution of these rocks: (1) near-isobaric cooling from 975 ° C to 875 ° C around 8 kbar. representation created by the formation of garnet porphyroblasts from spinel and quartz; and (2) co oling and decompression from 850 ° C. 8 kbar to below 750 ° C. 6.5 kbar, represented by the break-down of garnet. spinel + quartz assemblage is considered to have been stable at peak metamorphisni .formed through the break-down of cordierite. indicating a near isothermal compression process. Our study confirms the regional extent of UHT metamorphisni within the IMSZ associated with the Paleoproterozoic subduction-collision process.