Abstract We have investigated the petrology, U-Pb zircon ages, whole-rock geochemistry, and Hf–Sr-Nd isotopic compositions of the Hamisana Shear Zone granitoids (HSZG) in the Arabian-Nubian Shield (ANS) in northern Sudan in order to constrain their petrogenesis and tectonic setting of formation. The HSZG rocks consist mainly of granite, quartz syenite, and quartz monzonite that collectively make up two major groups based on their ages and geochemical compositions. The older group (average U-Pb zircon age of ~663 Ma) is represented by calc-alkaline and I-type peraluminous granites, whereas the younger group (average U-Pb zircon age 623.5 Ma) is characterized by A-type and metaluminous monzonitic intrusions. All rocks show high Al2O3, La/Nb, Th/Ta, Ba/Nb ratios, and similar REE patterns indicating enrichment of LILEs (Ba, K, Pb, and Sr) and depletion of HFSEs (Nb, Ta, Sm, P, and Ti), consistent with the characteristics of subduction-related magmas. La/Yb, La/Sm, Th/Nb, Rb/Sr, and Rb/Ba ratios suggest that magmas of the HSZG formed by partial melting of a subduction-modified mantle beneath the ANS. Sr-Nd isotopic compositions of both groups with Nd model ages of 794–877 Ma have eNd(t) values of +5.24 to +6.10. In-situ Hf isotope analyses indicate eHf(t) values of +10.36 to +10.90 for the older granites and +9.9 to +10.73 for the younger quartz monzonites. These isotopic features point to a depleted mantle source of their magmas with no involvement of Pre-Neoproterozoic crust in their melt evolution. The older HSZG granite suites represent pre-collision arc magmatism, whereas the younger HSZG quartz monzonite suites mark post-collisional magmatic units. Both magmatic events contributed significantly to juvenile crust construction during the Neoproterozoic assembly of the ANS.

中文翻译：

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苏丹北部哈米萨纳剪切带花岗岩的年代学、地球化学和 Hf-Sr-Nd 同位素：努比亚地盾新元古代地壳的岩石成因和构造演化

摘要 我们调查了苏丹北部阿拉伯-努比亚地盾 (ANS) 中哈米萨纳剪切带花岗岩 (HSZG) 的岩石学、U-Pb 锆石年龄、全岩地球化学和 Hf-Sr-Nd 同位素组成，以便限制它们的成岩作用和构造环境。HSZG 岩石主要由花岗岩、石英正长岩和石英二长岩组成，它们根据年龄和地球化学成分共同构成两大类。老组（平均 U-Pb 锆石年龄约 663 Ma）以钙碱性和 I 型过铝质花岗岩为代表，而年轻组（平均 U-Pb 锆石年龄 623.5 Ma）以 A 型和金属铝质花岗岩为特征二长侵入。所有岩石都显示出高 Al2O3、La/Nb、Th/Ta、Ba/Nb 比率和类似的 REE 模式，表明 LILEs（Ba、K、Pb、和 Sr) 和 HFSEs (Nb、Ta、Sm、P 和 Ti) 的消耗，与俯冲相关岩浆的特征一致。La/Yb、La/Sm、Th/Nb、Rb/Sr 和 Rb/Ba 比率表明 HSZG 的岩浆是由 ANS 下方俯冲改造地幔的部分熔融形成的。Nd 模型年龄为 794-877 Ma 的两组的 Sr-Nd 同位素组成具有 +5.24 至 +6.10 的 eNd(t) 值。原位 Hf 同位素分析表明，较老的花岗岩的 eHf(t) 值为 +10.36 至 +10.90，较年轻的石英二长岩的 eHf(t) 值为 +9.9 至 +10.73。这些同位素特征表明其岩浆的地幔来源已耗尽，而在其熔体演化过程中未涉及前新元古代地壳。较老的 HSZG 花岗岩组代表碰撞前的弧岩浆作用，而年轻的 HSZG 石英二长岩组代表碰撞后的岩浆单元。