ON THE EASTWARD EXTENSION OF THE NEI MONGOL AXIS

The Tieling-Jingyu uplift in the northern Liaoningsouthern Jilin region and the Nei Mongol asis in the Jianping-Fuxin region and areas west of it are characterized by the same Archean （2500±50 Ma） granulite-amphibolite-facies metamorphic crystalline rock series. Like the Nei Mongol axis, the Jieling-Jingyu uplift has the overlaps of middle and upper Proterozoic and Paleozoic strata, but they were not connected with the sea of the geosynclinal region to the north. The bundary between the Sino-Korean paraplatform and the geosynclinal region to its north is the Chifeng-Kaiyuan fault zone, which extends eastwards into the northern part of Korea. This indicates that the Tieling-Jingyu uplift and the Nei Mongol axis are alike: both serve as the natural barrier separating the geosynclinal region to their north from the platform region to their south and have the attribute of an axis. It is evident that the assignment of the Tieling-Jingyu uplift to a third-order tectonic unit cannot express this feature, so it should be assigned to the eastward extension of the Nei Mongol axis.