Using a combination of microstructural, spectroscopic, and geochemical analyses, we investigate how subgrain rotation recrystallization and fluid migration affect Ti concentration [Ti] in naturally deformed quartz veins from the Prijakt Nappe (Austroalpine Unit, Eastern Alps). These coarse-grained quartz veins, that formed at amphibolite facies conditions, were overprinted by lower greenschist facies deformation to different degrees. During the overprint, subgrain rotation recrystallization was dominant during progressive deformation to ultramylonitic stages. The initial [Ti] (3.0–4.7 ppm) and cathodoluminescence (CL) signature of the vein crystals decrease during deformation mainly depending on the availability of fluids across the microstructure. The amount of strain played a subordinate role in resetting to lower [Ti] and corresponding darker CL shades. Using a microstructurally controlled analysis we find that the most complete re-equilibration in recrystallized aggregates ([Ti] of 0.2–0.6 p.m.) occurred (a) in strain shadows around quartz porphyroclasts, acting as fluid sinks, and (b) in localized microshear zones that channelized fluid percolation. [Ti] resetting is mainly observed along wetted high angle boundaries (misorientation angle >10–15°), with partial [Ti] resetting observed along dry low angle boundaries (<10–15°). This study shows for the first time that pure subgrain rotation recrystallization in combination with dissolution-precipitation under retrograde condition provide microstructural domains suitable for the application of titanium-in-quartz geothermobarometry at deformation temperatures down to 300–350°C.

中文翻译：

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变形和流体对天然石英中钛交换的影响

结合微观结构、光谱和地球化学分析，我们研究了亚晶粒旋转再结晶和流体迁移如何影响来自 Prijakt Nape（南阿尔卑斯山脉，东阿尔卑斯山）的自然变形石英脉中的 Ti 浓度 [Ti]。这些在角闪岩相条件下形成的粗粒石英脉被较低的绿片岩相不同程度地套印。在叠印过程中，亚晶旋转再结晶在逐渐变形到超糜棱阶段期间占主导地位。脉状晶体的初始 [Ti] (3.0-4.7 ppm) 和阴极发光 (CL) 特征在变形期间减少，主要取决于微观结构中流体的可用性。应变量在重置以降低 [Ti] 和相应的较暗 CL 色调方面起次要作用。使用微观结构控制分析，我们发现重结晶聚集体中最完全的再平衡（[Ti] 为 0.2-0.6 pm）发生在（a）石英斑岩碎屑周围的应变阴影中，作为流体汇，（b）在局部微剪切中引导流体渗透的区域。[Ti] 重置主要沿湿润的高角度边界（取向角 >10-15°）观察到，沿干燥的低角度边界（<10-15°）观察到部分 [Ti] 重置。