Collision‐related granitoid batholiths, like those of the Hercynian and Himalayan orogens, are mostly fed by magma derived from metasedimentary sources. However, in the late Neoproterozoic calcalkaline (CA) batholiths of the Arabian–Nubian Shield (ANS), which constitutes the northern half of the East African orogen, any sedimentary contribution is obscured by the juvenile character of the crust and the scarcity of migmatites. Here, we use paired in situ LASS‐ICP‐MS measurements of U–Th–Pb isotope ratios and REE contents of monazite and xenotime and SHRIMP‐RG analyses of separated zircon to demonstrate direct linkage between migmatites and granites in the northernmost ANS. Our results indicate a single prolonged period of monazite growth at 640–600 Ma, in metapelites, migmatites and peraluminous granites of three metamorphic suites: Abu‐Barqa (SW Jordan), Roded (S Israel) and Taba–Nuweiba (Sinai, Egypt). The distribution of monazite dates and age zoning in single monazite grains in migmatites suggest that peak thermal conditions, involving partial melting, prevailed for c. 10 Ma, from 620 to 610 Ma. REE abundances in monazite are well correlated with age, recording garnet growth and garnet breakdown in association with the prograde and retrograde stages of the melting reactions, respectively. Xenotime dates cluster at 600–580 Ma, recording retrogression to greenschist facies conditions as garnet continued to destabilize. Phase equilibrium modelling and mineral thermobarometry yield P–T conditions of ~650–680°C and 5–7 kbar, consistent with either water‐fluxed or muscovite‐breakdown melting. The expected melt production is 8–10 vol.%, allowing a melt connectivity network to form leading to melt segregation and extraction. U–Pb ages of zircon rims from leucosomes indicate crystallization of melt at 610 ± 10 Ma, coinciding with the emplacement of a vast volume of CA granites throughout the northern ANS, which were previously considered post‐collisional. Similar monazite ages (c. 620 Ma) retrieved from the amphibolite facies Elat schist indicate that migmatites are the result of widespread regional rather than local contact metamorphism, representing the climax of the East African orogenesis.

中文翻译：

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阿拉伯-努比亚盾构北部的移民时期：与碰撞有关的岩基中的青少年沉积成分的证据

与碰撞有关的花岗岩类岩基，如海西和喜马拉雅造山带的岩基，主要是由沉积成岩来源的岩浆提供的。然而，在构成东非造山带北半部的新元古代钙盐碱性（CA）岩基的阿拉伯–努比亚盾（ANS）地壳中，由于其幼年特征和character石的稀缺性，掩盖了任何沉积作用。在这里，我们使用了独居石和xenotime的U-Th-Pb同位素比率和REE含量的成对LASS-ICP-MS测量，以及分离的锆石的SHRIMP-RG分析，以证明最北端ANS中的蒙脱石与花岗岩之间存在直接联系。我们的结果表明，在三个变质组的变质岩，辉锰矿和高铝质花岗岩中，独居石的生长时间延长了640-600 Ma：阿布·巴尔卡（约旦西南部），罗德（以色列南部）和塔巴·努韦巴（埃及西奈）。蒙脱石中独居石颗粒中独居石日期和年龄区的分布表明，主要的热条件包括部分熔融，主要存在于c。10马，从620到610马。独居石中的稀土元素丰度与年龄密切相关，记录石榴石的生长和石榴石的分解，分别与熔化反应的前进和后退阶段相关。Xenotime的日期聚集在600–580 Ma之间，记录了随着石榴石持续不稳定，向绿片岩相条件的倒退。相平衡建模和矿物thermobarometry产量对-叔温度约为650–680°C和5–7 kbar，与水熔法或白云母分解法一致。预期的熔体产量为8–10 vol。％，从而形成熔体连通网络，从而导致熔体分离和提取。来自白质体的锆石边缘的U–Pb年龄表明熔体在610±10 Ma处结晶，这与整个ANS北部大量的CA花岗岩的位置相吻合，以前被认为是碰撞后的。类似的独居石年龄（ç从角闪岩相埃拉特片岩检索。620马）表明，混合岩分布广泛的区域，而不是局部接触变质作用的结果，代表东非造山运动的高潮。