In this study, superimposed folds and antitaxial strain fringes are investigated to unravel the deformation path of the core zones of the Alpi Apuane metamorphic complex (northwest Tuscany Italy). Detailed field mapping combined with microstructural analyses is used together with computer-modelling of a complex strain fringe system to disclose the main steps of the Alpi Apuane syn-metamorphic deformation history. A comparison between natural investigated fibres and those produced by paraffine wax experiments provides details of the relative core-object-fringe rotation allowing new insight on the growth kinematics of strain fringes. The results of our analyses show that our composite fringe system is characterized by a first set of fibres to be related with the main composite axial planar foliation of regional scale isoclinal non-cylindric folds. This first set of fibre fringes records a local non-coaxial strain with an absolute core-object rotation (relative to an external reference frame represented by the main foliation) of 140° and a calculated shear strain (γ) of about 4. The second set of fringes, developed after the tilting of the main foliation and the first fringe-set in a sub-vertical orientation, records a lower absolute rotation of the core-object (25°), a lower shear strain (γ) of about 1.4 and a coaxial strain associated with the vertical shortening. This part of the composite fringe system and the related structures may relate to the switch from the crustal scale contractional regime to the extensional one, which characterized the development of the inner northern Apennines orogen.

在这项研究中，研究了叠加褶皱和反同轴应变条纹，以揭示 Alpi Apuane 变质杂岩（意大利托斯卡纳西北部）核心区的变形路径。结合微观结构分析的详细场映射与复杂应变条纹系统的计算机建模一起使用，以揭示 Alpi Apuane 同变质变形历史的主要步骤。天然研究纤维与石蜡实验产生的纤维之间的比较提供了相对核心-物体-边缘旋转的详细信息，从而对应变边缘的生长运动学有了新的认识。我们的分析结果表明，我们的复合边缘系统的特征在于第一组纤维与区域尺度等斜非圆柱褶皱的主要复合轴向平面叶理有关。第一组纤维条纹记录了一个局部非同轴应变，其中核心物体的绝对旋转（相对于由主叶理表示的外部参考系）为 140°，计算的剪切应变 (γ) 约为 4。在主叶理倾斜后形成的一组条纹和第一个亚垂直方向的条纹组记录了核心物体的较低绝对旋转（25°），较低的剪切应变（γ）约为 1.4以及与垂直缩短相关的同轴应变。这部分复合边缘系统及其相关构造可能与地壳尺度收缩状态向伸展状态的转变有关，这是亚平宁山脉北部内部造山带发育的特征。