Serpentine veins are ubiquitous in hydrated and deformed ultramafic rocks, and have previously been used to track fault kinematics and understand the evolution of environmental conditions during vein formation. However, difficulties in unambiguously identifying and mapping serpentine types at sub-micron to mm scales has limited our understanding of vein precipitation kinetics and growth histories. Using recently developed techniques of Raman spectroscopy mapping, combined with scanning- and transmission-electron microscopy, we describe a new type of mineralogically banded serpentine crack-seal vein in six samples from different settings around the world. In all of the studied samples, individual bands comprise a thin layer (∼0.4–2 μm) dominated by chrysotile and a much thicker layer (∼0.5–30 μm) dominated by polygonal serpentine/lizardite. Existing field and experimental data suggest that disequilibrium conditions immediately following crack opening may favour rapid precipitation of chrysotile along one of the crack margins. Subsequently, diffusional transport of elements favours slower precipitation of polygonal serpentine/lizardite which leads to crack sealing. The similarities in layer thicknesses and mineralogy exhibited by samples collected from extension and shear veins, dilational jogs, foliation surfaces, and the margins of phacoids, suggest that a common set of processes involving crack opening and sealing are active in a range of different structural sites within serpentinite-bearing faults and shear zones, potentially associated with repetitive slip events such as small repeating earthquakes.

蛇纹石脉在水合变形的超镁铁质岩石中无处不在，并且以前已被用来跟踪断层运动学并了解静脉形成过程中环境条件的演变。然而，难以明确地识别和绘制亚微米至毫米级蛇纹石类型的困难限制了我们对静脉沉淀动力学和生长历史的理解。使用最近开发的拉曼光谱作图技术，结合扫描电子显微镜和透射电子显微镜，我们在来自世界各地不同设置的六个样本中描述了一种新型的矿物学带状蛇形裂纹密封静脉。在所有研究的样本中，单个谱带包括由温石棉为主的薄层（约0.4–2μm）和由多边形蛇纹石/蜥蜴石为主的厚得多的层（约0.5–30μm）。现有的现场和实验数据表明，裂缝开裂后立即出现的不平衡条件可能有利于温石棉沿裂缝边缘之一快速沉淀。随后，元素的扩散传输有利于多边形蛇纹石/蜥蜴石的缓慢沉淀，从而导致裂缝密封。从延伸和剪切脉，膨胀的飞梭，叶面和类固醇的边缘收集的样品显示出的层厚度和矿物学的相似性表明，一组涉及裂纹开裂和密封的通用过程在一系列不同的结构部位都活跃。含蛇纹岩的断层和剪切带内，可能与重复的滑动事件（如小地震）有关。