The MAR 13°20′N corrugated detachment fault is composed of pervasively silicified mafic cataclastic breccias, instead of ultramafics and gabbros commonly found at other detachments. These breccias record overplating of hangingwall diabases, with syntectonic silicification due to important influx of silica‐iron‐rich fluids, able to leach alkalis and calcium. Fluids trapped in quartz inclusions show important salinity variations (2.1–10 wt.% NaCl eq.) indicating supercritical phase separation. Fluid inclusions also contain minor amounts of H₂ ± CO₂ ± CH₄ ± H₂S, with high H₂/CO₂ and H₂/H₂S ratios, signatures typical of ultramafic‐hosted vent fluids. We propose that seawater infiltrated the hangingwall upper crust at the axis adjacent to the active detachment, reaching a reaction zone at the dyke complex base (∼2 km). At >500°C, fluids become Si‐rich during diabase alteration (amphibolite‐facies alteration in clasts), and undergo phase separation. Brines, preferentially released in the nearby detachment fault during diabase brecciation, mix with serpentinite‐derived fluids bearing H₂ and CH₄. Cooling during detachment deformation and fluid upward migration triggers silica precipitation at greenschist‐facies conditions (quartz + Fe‐rich‐chlorite ± pyrite). Important variations in fluid inclusion salinity and gas composition at both sample and grain scales record heterogeneous fluid circulation at small spatial and short temporal scales. This heterogeneous fluid circulation operating at <2 km depth, extending both along‐axis and over time, is inconsistent with models of fluids channeled along detachments from heat sources at the base of the crust at the fault root. Present‐day venting at detachment footwall, including Irinovskoe, is instead likely underlain by fluid circulation within the footwall, with outflow crossing the inactive detachment fault near‐surface.

中文翻译：

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沿海洋拆离断层的流体循环：硅化角砾岩断层流体中夹杂物的见解（北大西洋中脊13°20′N）

MAR 13°20′N波纹状松动断层由普遍硅化的铁镁质碎裂角砾岩组成，而不是其他支系中常见的超镁铁质和辉长岩。这些角砾岩记录了上盘辉绿岩的过度镀覆，由于大量硅铁富集流体的渗入，从而能够渗出碱金属和钙，导致构造硅化作用。夹杂在石英夹杂物中的流体显示出重要的盐度变化（2.1-10 wt。％NaCl当量），表明超临界相分离。流体包裹体还包含少量的H ₂  ±CO ₂  ±CH ₄  ±H ₂ S，具有较高的H ₂ / CO ₂和H ₂ / H ₂S比值，超基体放空流体的典型特征。我们认为，海水在与活动分离线相邻的轴线处渗入了上盘壁上地壳，到达了堤防复合体基部的反应区（约2 km）。在> 500°C的温度下，辉绿岩蚀变期间流体中的硅富集（碎屑中闪石相的变化），并经历相分离。辉绿岩在辉绿岩成岩过程中优先释放在附近的松动断层中，与蛇纹岩衍生的H ₂和CH ₄流体混合。脱离变形过​​程中的冷却和流体的向上迁移会在绿片岩相条件下（石英+富铁亚氯酸盐±黄铁矿）触发二氧化硅沉淀。样品和谷物尺度上流体包裹体盐度和气体组成的重要变化都记录了在小空间和短时间尺度上的非均质流体循环。这种在<2 km深度运行的非均质流体循环，沿轴向和随时间都扩展，这与沿断层根部地壳底部热源的分离带走的流体模型是不一致的。如今，包括Irinovskoe在内的分离底盘的通气很可能是由于底盘内的流体循环所致，流出物横穿了近地表的非活动分离断层。