Abstract In this study, zircon grains are applied for U–Pb dating, Hf isotopes and trace elements to reveal the origin of magmatism and tectonic evolution of Late Paleozoic rocks of the Indian plate, Northern Pakistan. Most of the zircons are characterized by oscillatory zoning, depletion of light rare earth elements (LREE) and enrichment of heavy rare earth elements (HREE) with Ce and Eu anomalies. The yielded ages for these rocks are 256 ± 1.9 Ma and are plotted in the zones defined for the continental setting with few deviated toward the mid-oceanic ridge and the oceanic arc setting. Deviated zircons are recognized as inherited zircons by displaying a high concentration of normalized primitive La and Pr values, while others are plotted in the continental zones. Rare earth elements (REE) and trace elements including Th, Hf, U, Nb, Sc and Ti discriminate Swat orthogneisses into the within plate setting and the inherited zircons are plotted in the orogenic or the arc-related setting. The LREE discriminated these zircons into a magmatic zone with inherited zircons deviated toward the hydrothermal zone. The temperature calculated for these rocks based on the Ti content in zircon ranges from 679 to 942°C. The ε Hf(t) ranging from −11.1 to +1.4 reveals that the origin is the continental crust with the minute input of the juvenile mantle.

中文翻译：

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巴基斯坦北部斯瓦特正片麻岩锆石的年代学、微量元素和 Hf 同位素地球化学

摘要 本研究利用锆石颗粒进行U-Pb定年、Hf同位素和微量元素测定，揭示巴基斯坦北部印度板块晚古生代岩石的岩浆作用和构造演化。大多数锆石的特征是振荡分带，轻稀土元素（LREE）耗尽，重稀土元素（HREE）富集，Ce和Eu异常。这些岩石的屈服年龄为 256 ± 1.9 Ma，绘制在为大陆环境定义的区域内，很少偏向大洋中脊和大洋弧环境。偏斜锆石通过显示高浓度的归一化原始 La 和 Pr 值而被识别为继承锆石，而其他锆石则绘制在大陆带中。稀土元素 (REE) 和微量元素，包括 Th、Hf、U、Nb、Sc 和 Ti 将斯瓦特正片麻岩区分为板内环境，而继承的锆石绘制在造山带或与弧相关的环境中。轻稀土元素将这些锆石判别为岩浆带，继承的锆石偏向热液带。根据锆石中的 Ti 含量计算出的这些岩石的温度范围为 679 至 942°C。ε Hf(t) 范围从-11.1 到+1.4 表明起源是大陆地壳，有幼年地幔的微小输入。根据锆石中的 Ti 含量计算出的这些岩石的温度范围为 679 至 942°C。ε Hf(t) 范围从-11.1 到+1.4 表明起源是大陆地壳，有幼年地幔的微小输入。根据锆石中的 Ti 含量计算出的这些岩石的温度范围为 679 至 942°C。ε Hf(t) 范围从-11.1 到+1.4 表明起源是大陆地壳，有幼年地幔的微小输入。