Since the pioneering works of John Ramsay in the 1970's and 1980's, the analysis of exceptional exposures of small-scale shear zones (i.e. 10^-3 – 10⁻¹ m thick) in granitoid rocks provided invaluable insights into the processes controlling strain localisation in the middle and lower continental crust. Indeed, recent advancement in field, microstructural and petrological analyses of such small-scale shear zone have shed new light on the metamorphic, tectonic and fluid conditions promoting shear zone nucleation and development in granitoid rocks. In this paper we provide an overview of these new insights, comparing and integrating the results obtained from field, and microstructural and petrological analyses of small-scale shear zones in granitoid plutons and meta-granitoids from the Alps. A review of the deformation temperature shows that the granitoid shear zones development occurs between 350 and 600 °C, with most of them localising in a restricted temperature window between 450 and 500 °C. At these conditions, the magmatic assemblage is metastable and subjected to a series of metamorphic reactions. Furthermore, the development of shear zone does not occur under-closed system conditions. Introducing or expelling fluids and mass (i.e. metasomatism) during deformation has mineralogical consequences that control the rheology and the way shear zone evolves. Among the main mineralogical and microstructural changes, the breakdown of magmatic feldspar(s) into fine-grained aggregates steers both the rheology and fabric evolution of shear zones in granitoid rocks, triggering further mechano-chemical feedback mechanisms. Future research should consider the occurrence of feedback processes between deformation, metamorphic and metasomatic processes to understand and quantify the evolution with time and strain of shear zone geometry and rheology, as well as of the development of larger-scale shear zone networks.

自 1970 年代和 1980 年代 John Ramsay 的开创性工作以来，对小规模剪切带（即 10 ^-3 – 10 ^-1 m 厚）在花岗质岩石中为控制中下大陆地壳应变定位的过程提供了宝贵的见解。事实上，这种小尺度剪切带的现场、微观结构和岩石学分析的最新进展为促进花岗岩中剪切带成核和发育的变质、构造和流体条件提供了新的启示。在本文中，我们概述了这些新见解，比较和整合了从野外获得的结果，以及阿尔卑斯山花岗岩体和变花岗岩中小尺度剪切带的微观结构和岩石学分析。对变形温度的回顾表明，花岗岩剪切带的发育发生在 350 至 600 °C 之间，其中大部分位于 450 至 500 °C 之间的受限温度窗口内。在这些条件下，岩浆组合是亚稳态的，会发生一系列变质反应。此外，剪切带的发展不会发生在封闭系统条件下。在变形过程中引入或排出流体和物质（即交代作用）具有控制流变学和剪切带演变方式的矿物学后果。在主要的矿物学和微观结构变化中，岩浆长石分解成细粒聚集体控制着花岗岩剪切带的流变学和组织演化，触发了进一步的机械化学反馈机制。未来的研究应考虑变形、变质和交代过程之间反馈过程的发生，以了解和量化剪切带几何形状和流变随时间和应变的演变，