论文部分内容阅读
产于伊比利亚海西期构造带内带的中央埃斯特雷马杜拉(Extremadura)岩基构成一条重要的线状排列的岩体群。该岩基共包含13个深成岩体和许多较小的侵入体,其岩性变化范围较宽,从石英闪长岩到碱性长石花岗岩。通过对各个岩体的构造研究发现,岩体的内部构造型式彼此是有联系的。岩体内不同构造型式间的相互联系和沉积变质围岩中叠加构造变形解析均表明,岩体的侵位和变形产生于第二变形期(320-302百万年)的E-W向右旋陆内剪切带中。因此提出如下定性上升模式:(1)与E-W向右旋剪切带呈45°方向的引张破裂产生;(2)花岗质岩浆沿破裂面侵入;(3)早期侵入体发生右行旋转,导致形成对偶剪切带(即N-S向左旋)、垂直于早期岩体长轴的横向缩短作用、变形岩体以及晚期岩体的强制性侵位。
The central Extremadura bedrock, produced in the Hercynian structural belt of Iberia, forms an important linear arrangement of rock masses. The rock base contains a total of 13 deep plutons and many smaller intrusions, which vary widely in lithology, from quartz diorite to basic feldspar granite. Through the study of the structure of each rock mass, it is found that the internal structure types of the rock mass are related to each other. The interdependence between different structural types in the rock mass and the superimposed tectonic deformation analysis in the sedimentary metamorphic rocks indicate that the emplacement and deformation of the rock mass are caused by the EW trending rightward during the second deformation period (320-302 million years) Within the shear band. Therefore, the qualitative ascending model is proposed as follows: (1) The extension of the extensional fracture at 45 ° to the right-hand shear band of the EW occurs; (2) the intrusive granitic magma breaks along the fracture surface; (3) , Leading to the formation of dual shear band (ie, NS to the left), lateral shortening perpendicular to the major axis of early rock mass, deformed rock mass and forced emplacement of late rock masses.