【摘要】 位于中亚造山带东段的兴安地块和松辽锡林浩特地块被晚古生代贺根山-黑河缝合带分开。随后,大兴安岭与松辽盆地被中新生代嫩江-八里罕断裂分开。在大兴安岭中段,这两构造带的位置及板块拼合时间尚不明确。为研究大兴安岭中段东缘重要构造断裂、构造单元及结晶基底属性特征,在扎兰屯-阿荣旗地区采集处理一条长60 km的重力、磁法和大地电磁数据,重新处理了1:20万扎兰屯幅、阿荣旗幅区域布格重力异常数据。通过多种地球物理数据融合,解译了7条重要断裂,其中庞家街断裂和红星断裂是控制贺根山-黑河缝合带的深大断裂。北西向阿伦河断裂为深大断裂,至少切割到中地壳。发现了两个中地壳低阻带,其中C2异常解释为贺根山-黑河缝合带。通过1:25万阿荣旗幅地质填图资料,证实了地球物理数据融合的推断结果,为大兴安岭中段东缘构造带演化研究提供了重要支撑。更多还原

【Abstract】 Located at the east segment of Central Asian orogenic belt, the Xing’an block and the SongliaoXilinhaote block were separated by the Hegenshan-Heihe suture. Likewise, Xingan block and Songliao block were separated by the Nenjiang fault subsequently. In the central segment of the Great Kinghan Range, these two structures overlap and are hardly to be distinguished. To investigate the structures of the Great Kinghan Range, we have acquired a 60-km-length gravity, magnetic and magnetotelluric coincident profile in Zhalantun-Arongqi area, Inner Mongolia, China. The 1:20000 Buguer gravity data in Zhanlan-Arongqi area were reprocessed. Through multiple geophysical fusions, seven important faults were inferred. Among them, the Pangjiajie fault, the Hongxing fault, and the Alunhe fault are deep faults, at least penetrating up to middle crust. In addition, two low-resistivity belts in the middle curst were revealed, among which, C2 anomaly is interpreted as Hegenshan-Heihe suture. By correlating with 1:25000 geological mapping data, the geophysical interpretation results were proven. The research outcomes are helpful to geological studies of crustal structures at the central-east Great Kinghan Range margin.更多还原