【摘要】 新疆库鲁克塔格地区发育大量密集的岩墙群,反映了该区所经历的岩浆活动及地壳伸展事件。本文基于多源遥感影像(Landsat 7 ETM+、SPOT、CORONA KH-4B、QuickBird2)共提取了区内2284条岩墙,在此基础上进行几何学分析和岩浆超压估算。这些岩墙主要侵入新元古代侵入岩及前寒武系沉积岩和变质岩。走向以NW向(300°~320°)为主,同时存在NE向(40°~70°)和近东西向岩墙。岩墙单体长90m~22.8km,平均4.3km,呈对数正态分布。垂直岩墙走向,沿NE60°方向取4条剖面计算地壳伸展率,由北至南分别为4.22%、1.83%、2.60%和7.40%。根据岩墙纵横比(长度/厚度),计算获得岩墙侵位时岩浆超压为7.9MPa(E=10GPa)~23.7MPa(E=30GPa)。该区同时出露新元古代和二叠纪岩墙群,其空间分布与花岗岩有密切关联,为多种构造背景的产物,且经历了多期构造叠加和改造。更多还原

【Abstract】 Large-scale of mafic dyke swarms are widely distributed in Kuluktag region in Xinjiang,NW China,which indicates magmatic thermal events and crustal extensional events. Based on multisource high-resolution remote sensing images( Landsat 7 ETM + 、SPOT、CORONA KH-4B、QuickBird2),we extracted 2284 dykes to analyze the geometric feature and to estimate the magma overpressures. The exposed dykes mainly intruded Neoproterozoic intrusive rocks,Precambrian sedimentary rocks and metamorphic rocks. The results show that the NW( 300° ~ 320°) dykes dominate,followed by the NE( 40° ~ 70°) dykes and nearly EW-trending dykes. With a mean value of 4. 3km,the length of dykes ranges from 90m to 22. 8km and is statistical law with log-normal. According to 4 section lines of NE-trending( 60°),the crustal extension are 4. 22% 、1. 83% 、2. 60% and 7. 40% from north to south. Using the aspect( length / thickness) ratios of the dykes,the magma overpressures at their time of emplacement are estimated. Most values indicate overpressures between 7. 9MPa( E = 10GPa) and 23. 7MPa( E = 30GPa). The dyke swarms appear to be two ages of Neoproterozoic and Permian in this region,the spatial distribution of which is closely related with granites. These dyke swarms have experienced several tectonic and deformation events,and are likely to be the results of various tectonic background.更多还原