Late Mesozoic granitoids are widely emplaced in the Qinling Orogen on the southern margin of North China Craton (NCC), and can provide important clues on the Late Mesozoic regional geodynamic setting. The Late Jurassic Laoniushan granitic pluton is located in the western end of the southern NCC margin. Zircon U–Pb dating for the granodiorite, quartz diorite, and biotite monzogranite of the pluton yielded 152.5 ± 1.6 Ma, 148.7 ± 1.2 Ma, and 149–146 Ma, respectively. Compilation of the single zircon ages revealed magmatic peaks at ca. 146, 152, and 163 Ma, suggesting multiphase Late Jurassic magmatism. These granitoids are high‐K calc‐alkaline, I‐type, and metaluminous to weakly peraluminous. The rocks show chondrite‐normalised LREE enrichments, HREE depletions and flat HREE patterns, together with (slightly) negative Eu, Nb, Ta, P, and Ti anomalies. The Laoniushan granodiorite and biotite monzogranite have similar REE patterns to the quartz diorite, but the former two have much smaller Eu anomalies than the latter. The negative zircon ε_Hf(t) (−32.6 to −13.7), ε_Nd(t) (−20.7 to −14.3) and crustal‐like whole‐rock trace‐elemental ratios (e.g., Nb/Ta, Th/U, Nb/U, and Ce/Pb), together with the low Mg (MgO = 0.18–2.02 wt%, Mg^# = 20–34), Cr (7.00–39.0 ppm), and Ni (0.80–4.00 ppm) contents, suggests that the Late Jurassic granitoids were probably derived from the partial melting of ancient crustal rocks with minor mantle‐derived input. The granodiorite and quartz diorite have similar average ε_Hf(t) (−26.5 and −26.7, respectively), ε_Nd(t) (−20.5 and −20.2, respectively), T_DM2(Hf) (2880 and 2885 Ma, respectively) and T_DM2(Nd; 2607 and 2578 Ma, respectively), whereas the biotite monzogranite has higher average ε_Hf(t) (−17.1) and ε_Nd(t) (−15.3), and younger T_DM2(Hf) (2281 Ma) and T_DM2(Nd) (2176 Ma). This suggests that the biotite monzogranite has different magma sources and shallower magma formation depths compared to the granodiorite and quartz diorite. The latter two were likely formed by the partial melting of continental crustal rocks (notably the Taihua Group basement rocks), which was triggered by mantle underplating led by asthenospheric upwelling. The Late Jurassic Laoniushan granitoids may have formed in an extensional setting caused by the Palaeo‐Pacific Plate subduction beneath Eastern China. Commencement of Late Jurassic Laoniushan granitic magmatism likely marked the incipient of lithospheric thinning along the southern NCC margin. Considering also the regional geological evolution, we conclude that although the Laoniushan pluton exhibits spatial–temporal relationships with the nearby Mo (–U) and REE deposits, there is still no unambiguous metallogenic link with these deposits.

中文翻译：

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华北克拉通西南缘侏罗纪晚期Laoniushan岩体多相岩浆套印：年代学和岩石成因

晚中生代花岗岩广泛分布于华北克拉通（NCC）南缘的秦岭造山带中，可以为晚中生代区域地球动力学环境提供重要线索。侏罗纪晚期Laoniushan花岗岩岩体位于NCC南部边缘的西端。锆石的U–Pb年龄分别为152.5±1.6 Ma，148.7±1.2 Ma和149-146 Ma，分别为花岗闪长岩，石英闪长岩和黑云母辉长岩。单一锆石年龄的汇编揭示了约于157℃的岩浆峰。146、152和163 Ma，表明为多相晚侏罗世岩浆作用。这些花岗石为高钾钙碱性，I型，金属质至弱铝质。岩石显示出球粒陨石归一化的LREE富集，HREE耗尽和平坦的HREE模式，以及（轻微）负Eu，Nb，Ta，P和Ti异常。老牛山花岗闪长岩和黑云母辉长花岗岩具有与石英闪长岩相似的REE模式，但前两者的Eu异常比后者小得多。负锆石ε_的Hf（吨）（-32.6 -13.7到），ε_的Nd（吨）（-20.7至-14.3）和地壳状全岩痕量元素比率（例如，NB /钽，钍/ U，NB / U ，Ce / Pb）以及低的Mg（MgO = 0.18–2.02 wt％，Mg ^＃ = 20–34），Cr（7.00–39.0 ppm）和Ni（0.80–4.00 ppm）含量，表明侏罗纪晚期的花岗岩类可能来自古地壳岩石的少量融化，而地幔来源的输入较小。花岗闪长岩和石英闪长岩具有相似的平均ε_的Hf（吨）（-26.5和-26.7，分别地），ε_的Nd（吨）（-20.5 -20.2和，分别地），Ť _DM2（HF）（2880和2885麻，分别地）和Ť _DM2（ND; 2607和2578麻，分别地），而黑云母二长花岗岩具有较高的平均ε_的Hf（吨）（-17.1）和ε_的Nd（吨）（-15.3 ），以及更年轻的T _DM2（Hf）（2281 Ma）和T _DM2（Nd）（2176毫安）。这表明与花岗闪长岩和石英闪长岩相比，黑云母辉长花岗岩具有不同的岩浆来源和较浅的岩浆形成深度。后两者可能是由于大陆地壳岩石（尤其是太华集团基底岩石）的部分熔融而形成的，这是由于软流圈上升引起的地幔下盘作用引起的。晚侏罗世Laoniushan花岗岩可能是在华东地区下古太平洋板块俯冲作用引起的伸展作用下形成的。晚侏罗世Laoniushan花岗岩岩浆作用的开始可能标志着NCC南部边缘岩石圈变薄的开始。还考虑到区域地质演化，我们得出的结论是，尽管Laoniushan岩体与附近的Mo（–U）和REE矿床表现出时空关系，