We investigated a suite of metabasite blocks from serpentinite matrix and shale matrix mélanges of the California Coast Ranges. Our new data set consists of ⁴⁰Ar/³⁹Ar dates of amphibole and phengite and U‐Pb dates of metamorphic zircon. Combined with published geochronology, including prograde Lu‐Hf garnet ages from the same blocks, we can reconstruct the timing and time scales of prograde and retrograde metamorphism of individual blocks. In particular we find that exhumation from amphibole‐eclogite facies conditions occurred as a single episode at 165–157 Ma, with an apparent southward younging trend. The rate and timing of exhumation were initially uniform (when comparing individual blocks) and fast (with cooling rates up to ~140°C/Ma). In the cooler and shallower blueschist facies, exhumation slowed and became less uniform among blocks. Considering the subduction zone system, the high‐grade exhumation temporally correlates with a magmatic arc pulse (Sierra Nevada) and the termination of forearc spreading (Coast Range Ophiolite). Our findings suggest that a geodynamic one‐time event led to exhumation of amphibole‐eclogite facies rocks. We propose that interaction of the Franciscan subduction zone with a spreading ridge led to extraction of the forearc mantle wedge from its position between forearc crust and subducting crust. The extraction led to fast and uniform exhumation of subducted rocks into the blueschist facies. We also show that the Franciscan subduction zone did not undergo significant cooling over time and that its initiation was not coeval with blueschist‐facies metamorphism of the Red Ant schist of the Sierra Nevada foothills.

中文翻译：

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新生方济各斯俯冲带（美国加利福尼亚州）的掘尸脉冲

我们研究了加利福尼亚海岸山脉蛇纹岩基质和页岩基质混杂岩的一组异位块。我们的新数据集包括⁴⁰ Ar / ³⁹闪石和变石的Ar日期和变质锆石的U-Pb日期。结合已发表的地质年代学，包括同一区块的渐进Lu-Hf石榴石年龄，我们可以重构单个区块的前进和后退变质的时间和时间尺度。尤其是，我们发现闪石-榴辉岩相条件的发掘是在165-157 Ma内单发发生，并且有明显的向南年轻化趋势。掘尸的速率和时间最初是统一的（与单个块进行比较时），并且速度很快（冷却速率高达〜140°C / Ma）。在较冷和较浅的蓝片岩相中，尸体的发掘速度减慢并且变得不太均匀。考虑俯冲带系统 高级发掘与岩浆弧脉冲（内华达山脉）和前臂扩展的终止（海岸蛇绿岩）在时间上相关。我们的发现表明，一次地球动力学事件导致了闪石-榴辉岩相岩的掘出。我们提出方济各会俯冲带与扩张脊的相互作用导致前臂地幔楔从其在前地壳与俯冲地壳之间的位置中抽出。提取导致俯冲岩石快速统一地发掘到蓝片岩相中。我们还显示，方济各斯俯冲带并没有随着时间的流逝经历明显的降温，并且它的萌发与内华达山脉山麓的红蚂蚁片岩的蓝片岩相变质并存。我们的发现表明，一次地球动力学事件导致了闪石-榴辉岩相岩的掘出。我们提出方济各会俯冲带与扩张脊的相互作用导致前臂地幔楔从其在前地壳与俯冲地壳之间的位置中抽出。提取导致俯冲岩石快速统一地发掘到蓝片岩相中。我们还显示，方济各斯俯冲带并没有随着时间的流逝经历明显的降温，并且它的萌发与内华达山脉山麓的红蚂蚁片岩的蓝片岩相变质并存。我们的发现表明，一次地球动力学事件导致了闪石－榴辉岩相岩的掘出。我们提出方济各会俯冲带与扩张脊的相互作用导致前臂地幔楔从其在前地壳与俯冲地壳之间的位置中抽出。提取导致俯冲岩石快速统一地发掘到蓝片岩相中。我们还显示，方济各斯俯冲带并没有随着时间的流逝经历明显的降温，并且它的萌发与内华达山脉山麓的红蚂蚁片岩的蓝片岩相变质并存。我们提出方济各会俯冲带与扩张脊的相互作用导致前臂地幔楔从其在前地壳与俯冲地壳之间的位置中抽出。提取导致俯冲岩石快速统一地发掘到蓝片岩相中。我们还显示，方济各斯俯冲带并没有随着时间的流逝经历明显的降温，并且它的萌发与内华达山脉山麓的红蚂蚁片岩的蓝片岩相变质并存。我们提出方济各会俯冲带与扩张脊的相互作用导致前臂地幔楔从其在前地壳与俯冲地壳之间的位置中抽出。提取导致俯冲岩石快速统一地发掘到蓝片岩相中。我们还显示，方济各斯俯冲带并没有随着时间的流逝经历明显的降温，并且它的萌发与内华达山脉山麓的红蚂蚁片岩的蓝片岩相变质并存。