As a common constituent of metamorphic assemblages, rutile provides constraints on the timing and conditions of rock transformation at high resolution. However, very little is known about the links between trace element mobility and rutile microstructures that result from synmetamorphic deformation. To address this issue, here we combine in situ LA‐ICP‐MS and sensitive high‐resolution ion microprobe trace element data with electron back‐scatter diffraction microstructural analyses to investigate the links between rutile lattice distortions and Zr and U–Pb systematics. Furthermore, we apply this integrated approach to constrain further the temperature and timing of amphibolite facies metamorphism and deformation in the Bergen Arcs of southwestern Norway. In outcrop, the formation of porphyroblastic rutile in dynamically hydrated leucocratic domains of otherwise rutile‐poor statically hydrated amphibolite provides key contextual information on both the ambient conditions of hydration and deformation and the composition of the reactive fluid. Rutile in amphibolite recorded ambient metamorphic temperatures of ~590–730°C during static hydration of the granulitic precursor. By contrast, rutile from leucocratic domains in the directly adjacent shear zone indicates that deformation was accompanied by a localized increase in temperature. These higher temperatures are recorded in strain‐free rutile (~600–860°C) and by Zr concentration measurements on low‐angle boundaries and shear bands (620–820°C). In addition, we also observe slight depletions of Zr and U along rutile low‐angle boundaries relative to strain‐free areas in deformed grains from the shear zone. This indicates that crystal–plastic deformation facilitated the compositional re‐equilibration of rutile upon cooling to slightly below the peak temperature of deformation. Cessation of deformation at mid‐crustal conditions near ~600°C is recorded by late stage growth of small (<150 µm) rutile in the high‐strain zones. U–Pb age data obtained from the strain‐free and distorted rutile grains cluster in distinct populations of 437.4 ± 2.7 Ma and c. 405–410 Ma, respectively. These different ages are interpreted to reflect the difference in closure for thermally induced Pb diffusion between undeformed and deformed rutile during post‐deformation exhumation and cooling. Thus, our results provide a reconstruction of the thermochronological history of the amphibolite facies rocks of the Lindås Nappe and highlight the importance of integration of microstructural data during application of thermometers and geochronometers.

中文翻译：

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变质金红石中微结构控制的痕量元素（Zr，U–Pb）的浓度：以卑尔根弧的闪石为例

作为变质组合的常见组成，金红石对高分辨率的岩石转化的时间和条件提供了限制。然而，人们对微量元素迁移率和由同形变形导致的金红石微结构之间的联系知之甚少。为了解决这个问题，这里我们将原位LA‐ICP‐MS和敏感的高分辨率离子微探针痕量元素数据与电子反向散射衍射微结构分析相结合，以研究金红石晶格畸变与Zr和U–Pb系统学之间的联系。此外，我们采用这种综合方法进一步限制了挪威西南部卑尔根弧上的闪石相变质和变形的温度和时间。在露头 在其他金红石贫化的静态水合闪石的动态水合白垩纪域中形成成卟啉金红石提供了有关水合和变形的环境条件以及反应性流体组成的关键背景信息。在颗粒状前驱体静态水化过程中，闪石中的金红石环境变质温度约为590-730°C。相比之下，直接相邻的剪切带中白垩纪域的金红石表明变形伴随着温度的局部升高。这些较高的温度记录在无应变金红石（〜600–860°C）和低角度边界和剪切带（620–820°C）的Zr浓度测量中。此外，我们还观察到，相对于剪切区变形晶粒中无应变的区域，沿金红石低角度边界的Zr和U略有耗尽。这表明晶体-塑性变形促进了金红石在冷却至稍低于变形峰值温度时的成分重新平衡。在高应变区中，约600°C的中地壳条件下变形的停止是由小（<150 µm）金红石的后期生长记录的。从无应变和扭曲的金红石晶粒簇获得的U–Pb年龄数据为437.4±2.7 Ma和 在高应变区中，约600°C的中地壳条件下变形的停止是由小（<150 µm）金红石的后期生长记录的。从无应变和扭曲的金红石晶粒簇获得的U–Pb年龄数据为437.4±2.7 Ma和 在高应变区中，约600°C的中地壳条件下变形的停止是由小（<150 µm）金红石的后期生长记录的。从无应变和扭曲的金红石晶粒簇获得的U–Pb年龄数据为437.4±2.7 Ma和C。分别为405–410 Ma。解释了这些不同的年龄，以反映变形后回火和冷却过程中未变形和变形金红石之间热诱导铅扩散的封闭差异。因此，我们的结果提供了LindåsNappe闪石岩相岩热年代学历史的重建，并突出了在使用温度计和地球计时器时整合微结构数据的重要性。