关于内蒙地轴的东延问题
ON THE EASTWARD EXTENSION OF THE NEI MONGOL AXIS
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摘要: 本文提出辽北和吉南地区,与内蒙地轴具有共同的地质构造特征,它们都发育了太古界麻粒岩一角闪岩相变质结晶基底岩系,相同的沉积盖层、变质变形作用、构造演化历史。因此,铁岭一靖宇隆起与内蒙地轴均为地轴性质,是北部地槽与南部地台的天然屏障。其北界沿赤峰一开原断裂带,向东经辽吉地区延入朝鲜,其南界大致沿太子河及鸭绿江凹陷的边缘断裂为界。Abstract: 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.