Abstract In order to clarify the link between 40Ar/39Ar record in white mica and deformation, we performed in situ and bulkwise 40Ar/39Ar dating over the East Tenda Shear Zone (Tenda massif, Alpine Corsica). White micas from 11 samples were selected and extensively analyzed using in situ techniques across nested scales of strain‐intensity gradients developed at the expense of a late‐Variscan protolith. 40Ar/39Ar systematics are unaffected by inherited Ar and directly linked to deformation with little or no Ar lattice (volume) diffusion. Extensive sampling allows constraining the end of deformation related to burial and exhumation, respectively, at ~34 and ~22 Ma, bracketing the duration of regional extensional shear to ~12 Myr. Results also highlight a regional strain localization toward the upper contact of the unit with smaller‐scale localization in specific lithologies, notably meta‐aplites. Second‐order complications exist, such as local ill‐defined correlations between ages and finite‐strain microstructures. Thus, the use of a strain gradient as a proxy for strain localization in time is regionally valid but sometimes locally too complex to track or resolve strain partitioning/localization trends at the meter (outcrop) scale and below. Age mixing and incomplete isotopic homogenization by dissolution/precipitation are identified as the main causes of local discrepancies that complicate the link between age and microstructure and the derivation of strain localization rates. Tracking temporal trends in shear distribution across regional‐scale deformation gradients in such settings is possible but requires a multi‐scale approach as implemented here to reveal younging patterns associated to strain localization.

中文翻译：

---

低温剪切带中白云母的原位和逐步加热 40 Ar/39 Ar 测年（Tenda Massif，高山科西嘉，法国）

摘要 为了阐明白云母中 40Ar/39Ar 记录与变形之间的联系，我们在东腾达剪切带（腾达地块，科西嘉高山）上进行了原位和体积 40Ar/39Ar 测年。选择了来自 11 个样品的白色云母，并使用原位技术在以晚期 Variscan 原岩为代价开发的应变强度梯度的嵌套尺度上进行了广泛分析。40Ar/39Ar 系统学不受继承 Ar 的影响，并且与几乎没有或没有 Ar 晶格（体积）扩散的变形直接相关。广泛的采样允许将与埋藏和挖掘相关的变形结束分别限制在 ~34 和 ~22 Ma，将区域拉伸剪切的持续时间限制在 ~12 Myr。结果还强调了单元上部接触的区域应变定位与特定岩性中的小尺度定位，特别是元 aplites。存在二阶并发症，例如年龄和有限应变微观结构之间局部不明确的相关性。因此，使用应变梯度作为时间应变定位的代理在区域上是有效的，但有时局部太复杂而无法在米（露头）尺度及以下跟踪或解决应变分区/定位趋势。年龄混合和溶解/沉淀不完全同位素均质化被确定为局部差异的主要原因，这些差异使年龄和微观结构之间的联系以及应变定位率的推导复杂化。