The Pamir gneiss domes represent the most extensive exposure of mid to lower crustal rocks in the Himalayan‐Tibetan orogen north of the India‐Asia suture zone. Unlike other domes in the Central and Southern Pamir, the Muztaghata dome stands out due to its higher metamorphic grade, more complex structural elements, and variable timing of metamorphism. In order to unravel the P‐T‐t history of the Muztaghata dome and better constrain the timing of peak metamorphism, we applied petrologic modeling in concert with geochronology to samples from the structure. The Muztaghata gneiss dome is composed of a structurally higher metapelite‐dominated terrane in the west and a structurally lower orthogneiss terrane in the east. Our results from the western terrane indicate high‐pressure eclogite facies peak conditions of ~800°C/22 kbar at ~25–20 Ma. Zircon grains from metapelitic samples from the western terrane also yield Early Jurassic metamorphic U‐Pb ages with REE signals that indicate coeval garnet growth. Our results from the eastern terrane record high‐pressure amphibolite facies peak conditions of ~650°C/14 kbar at ~24–20 Ma, noticeably lower than the structurally higher western terrane indicating structural juxtaposition during Miocene exhumation. Peak metamorphic conditions from the eastern terrane indicate depths below the current Moho, supporting the interpretation that the Early Miocene Pamir crust was thicker than present. This was followed by rapid exhumation from depths of ~75–80 km and partial westward collapse of the Pamir after 20 Ma, possibly driven in part by regional lithospheric delamination.

中文翻译：

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Muztaghata圆顶中新世榴辉岩相变质：东北帕米尔下地壳演化的记录

帕米尔片麻岩穹顶是印度-亚洲缝合带北部喜马拉雅-藏山造山带中中，下地壳岩石的最广泛暴露。与中帕米尔南部和南部帕米尔地区的其他穹顶不同，Muztaghata穹顶因其较高的变质等级，更复杂的结构元素和可变的变质时间而脱颖而出。为了弄清穆兹塔格塔圆顶的P‐T‐t历史并更好地限制峰变质的时间，我们将岩石学建模与地质年代学一起应用于结构样本。Muztaghata片麻岩穹顶由西部构造较高的变质岩为主的地层和东部构造较低的直斜构造岩层组成。我们从西部地层获得的结果表明，高压榴辉岩相在〜25-20 Ma时的峰值条件为〜800°C / 22 kbar。西部地层的成岩样品中的锆石晶粒也产生了侏罗纪早期的U-Pb变质时代，其REE信号表明了榴石的生长。我们从东部地层获得的结果表明，高压闪石岩相在〜24-20 Ma时达到约650°C / 14 kbar的峰值条件，明显低于构造上较高的西部地层，表明在中新世发掘期间结构并置。来自东部地层的峰值变质条件表明其深度低于当前的莫霍面，这支持了早中新世帕米尔地壳比现在厚的解释。随后是从大约75-80 km的深度快速发掘出石块，帕米尔（Pamir）在20 Ma之后向西坍塌，可能部分是由于区域岩石圈的分层所致。