【摘要】 磁组构是指岩石磁化率的各向异性,磁组构方法已经被广泛应用于构造变形分析。阿尔泰南缘东段地区岩石磁组构特征是磁各向异性度P值大,反映本区总体韧性剪切变形强烈。萨尔布拉克—科克萨依脆性劈理化带和玛因鄂博韧性剪压构造带的E>0占优势,磁面理发育,部分样品磁线理发育,反映变形以压扁变形为主,主压应力方向为NE(NEE)向,伴随弱的左行剪切;达拉维孜—阿热勒托别韧性流变构造带和锡泊渡—富蕴深层次变晶糜棱岩带E>0和E<0均存在,磁面理和磁线理均发育,反映以剪切变形为主;其中达拉维孜—阿热勒托别构造带主压应力方向为NE(NEE)向,为左行剪切,而锡泊渡—富蕴构造带主压应力方向为SN向,为右行剪切。在达拉维孜—阿热勒托别构造带中的哈腊苏铜矿和卡拉先格尔—老山口一带一些叠加蚀变矿化的强变形岩石的P值明显减小,说明在韧性变形之后发生过矿化热液作用导致磁化率各向异性发生了均一化。结合区域构造分析,可以认为萨尔布拉克—科克萨依构造带、达拉维孜—阿热勒托别构造带和玛因鄂博构造带构成一个完整的板块碰撞聚合带,而锡泊渡—富蕴构造带可能为在古生代期间被强烈改造的具有前震旦纪结晶基底的微大陆的残留(或断片)。更多还原

【Abstract】 The magnetic fabric represents rock’s susceptibility anisotropy. Magnetic fabric analytic method has been widely used in geology for structural deformation analysis. Magnetic fabric of the rocks in eastern part of southern Altay margin area, Xinjiang, northwest of China, shows that they have a high value of P, indicating that their magnetic anisotropy is prominent. E value of the rocks in the Sa’erbulake-Kekesayi brittle compressional cleavage belt and Mayin’ebo ductile shear-compressional belt was found to be greater than zero; magnetic foliation well developed and lineation developed only in a part of samples; implying that compressional deformation was well developed in the area. The sense of maximum compressive stress across the NW trending structural belts was NE (NEE) and there was partly a shear deformation along the belts with left-lateral shearing. In Dalaweizi-Areletebie shear rheomorphic belt and Xibodu-Fuyun deep ultra-ductile crystalloblast mylonite belt, rocks’ magnetic fabric showed well developed magnetic foliation and lineation, and their E value was either above zero or below zero, giving indications that these two belts were subjected to shear deformation, and that the sense of maximum compressive stress of Dalaweizi-Areletebie belt was NE (NEE) trending indicating a left-lateral shearing, but the sense of maximum compressive stress of Xibodu-Fuyun belt was SN trending showing a right-lateral shearing. Magnetic fabric analysis revealed that value of P of some altered-mineralized deformed rocks from Halasu Cu-deposit and Kalaxian’ge’er-Laoshankou area belonging to the Dalaweizi-Areletebie belt was very low, displaying that there were late mineralization and alteration weakened and isotropic susceptibility in the area. Combined with the regional structure analysis, we suggested that the three belts, i.e., the belts of Sa’erbulake-Kekesayi, Dalaweizi-Areletebie and Mayin’ebo, constituted a complete plate (micro landmass) condensation zone underthrusted by the Kalatongke island arc toward northeast to the Keketuhai-Qinghe magmatic arc and collision of the two arcs; and that the Xibodu-Fuyun belt was probably a relict (or a thin fault piece) of a micro-landmass with pre-Sinian crystalline basement reformed strongly in the Paleozoic.更多还原