Abstract The appearance of voluminous K-rich granitoid rocks during Late Archean marks gradual maturation and stabilization of the continental crust. While most K-rich granitoid magmatism followed TTG magmatism, they occur synchronously sometimes, and this relationship is crucial for our understanding of the evolution of late Archean continental crust and its geodynamic setting. In this study, a series of ~2.57–2.52 Ga coeval and diverse granitoid rocks, including quartz dioritic-trondhjemitic and granodioritic to monzo-/syenogranitic gneisses, were identified in the southern Fushun area of Eastern Liaoning Province, North China Craton. The ~2.57 Ga quartz dioritic gneisses show moderate MgO (≤ 3.96 wt.%) and moderate to high Mg# (37.3–75.5). Geochemical modeling, together with mildly fractionated REE patterns and negative Eu anomalies and depleted zircon ƐHf(t2) (+2.1 − +7.4), suggest that they were differentiated from a depleted mantle source that was metasomatized by slab-derived fluids. The younger trondhjemitic gneisses (~2.55–2.52 Ga) are divided into two subgroups, i.e., an older subgroup (~2547–2540 Ma) characterized by mildly fractionated REE patterns and negative Eu anomalies, and a younger subgroup (~2533–2517 Ma) with strongly fractionated REE patterns and positive Eu anomalies. The trondhjemitic gneisses lack evidence for magma differentiation, and they are inferred to have been formed by reworking of amphibolites/greywackes at diverse crustal levels, with some inputs of mantle materials in the earlier subgroup. The coeval ~2550–2529 Ma granodioritic and monzo-/syenogranitic gneisses are characterized by high K2O/Na2O (0.67–2.45) but low MgO and Mg# (mostly Taken together, the above granitoid rocks record gradually decreasing zircon ƐHf(t2) values and increasing crustal thickness. Considering the petrogenetic information, regional geological data and the presence of some ~3.45–2.70 Ga crustal materials, the late Neoarchean granitoid magmatism of southern Fushun were likely generated via complex crust-mantle interaction processes at an active continental margin. It is further emphasized that Archean active continental margins are key sites for the initial maturation of the crust, and this tectonic scenario acted as a trigger for granitoid diversification during both the subduction and subsequent collisional stages.

中文翻译：

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华北克拉通辽东活动大陆边缘新太古代晚期同步富钠钾花岗岩类岩浆作用

摘要 太古代晚期大量富钾花岗岩的出现标志着大陆地壳的逐渐成熟和稳定。虽然大多数富钾花岗岩类岩浆活动跟随TTG岩浆活动，但有时它们是同步发生的，这种关系对于我们理解晚太古代大陆地壳的演化及其地球动力学环境至关重要。在这项研究中，在辽宁东部抚顺南部、华北克拉通地区发现了一系列~2.57-2.52 Ga 同世和多样的花岗岩类岩石，包括石英闪长岩-长闪长岩和花岗闪长至二长/同花岗质片麻岩。~2.57 Ga 石英闪长片麻岩显示中等 MgO (≤ 3.96 wt.%) 和中等至高 Mg# (37.3–75.5)。地球化学建模，连同轻度分馏的 REE 模式和负 Eu 异常以及贫化锆石 ƐHf(t2) (+2.1 - +7.4)，表明它们与被板片衍生流体交代的贫化地幔源区分开来。较年轻的长闪长片麻岩 (~2.55–2.52 Ga) 分为两个亚组，即以轻度分异 REE 模式和负 Eu 异常为特征的较老亚组 (~2547–2540 Ma) 和年轻亚组 (~2533–2517 Ma ) 具有强烈分馏的 REE 模式和正 Eu 异常。长岩片麻岩缺乏岩浆分化的证据，推测它们是通过不同地壳水平的角闪岩/灰岩再加工形成的，其中一些早期亚群的地幔物质输入。考虑到岩石成因信息、区域地质资料和一些~3.45-2.70 Ga地壳物质的存在，抚顺南部晚新太古代花岗岩类岩浆活动可能是在活动大陆边缘通过复杂的壳幔相互作用过程产生的。进一步强调，太古代活动大陆边缘是地壳初始成熟的关键地点，这种构造情景在俯冲和随后的碰撞阶段都触发了花岗岩的多样化。考虑到岩石成因信息、区域地质资料和一些~3.45-2.70 Ga地壳物质的存在，抚顺南部晚新太古代花岗岩类岩浆活动可能是在活动大陆边缘通过复杂的壳幔相互作用过程产生的。进一步强调，太古代活动大陆边缘是地壳初始成熟的关键地点，这种构造情景在俯冲和随后的碰撞阶段都触发了花岗岩的多样化。