Mesoproterozoic (∼1.3 Ga) S–type granites in Shangdu area, Inner Mongolia of the North China Craton (NCC): Implications for breakup of the NCC from the Columbia supercontinent
Mesoproterozoic (∼1.3 Ga) S–type granites in Shangdu area, Inner Mongolia of the North China Craton (NCC): Implications for breakup of the NCC from the Columbia supercontinent
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DOI：
10.1016/j.precamres.2021.106515
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发表时间：
2022-02
影响因子：
3.8
通讯作者：
Chang‐hai Li;Zhenghong Liu;Zhongyuan Xu;Xiaojie Dong;Jin Liu;Yusong Cheng;Nuo Zhang
中科院分区：
文献类型：
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作者：
Chang‐hai Li;Zhenghong Liu;Zhongyuan Xu;Xiaojie Dong;Jin Liu;Yusong Cheng;Nuo Zhang
华北地区中元古代（1.3Ga）岩浆活动以闪长岩为特征，而现代花岗质岩浆活动相对较少，限制了对该时期华北地区岩浆演化的认识。在本文中，我们报道了在NCC北方西部的上都地区新发现的1.3 Ga S型花岗岩深圳湾。根据地球化学、年代学和锆石原位Lu-Hf同位素分析结果，讨论了花岗岩的成因、构造环境和NCC从哥伦比亚超大陆裂解的机制。锆石激光烧蚀电感耦合等离子体质谱（LA-ICP-MS）U-Pb定年结果表明，这些花岗岩侵位时间介于1315 ± 21 Ma ~ 1307 ± 32 Ma之间。地球化学结果表明，它们具有较高的SiO_2（75.34- 76.97wt%）、Al_2O_3（12.90- 13.61wt%）和Na_2 O + K_2 O（6.21- 8.31wt%）含量，而MgO（0.09- 0.25wt%）和Mg#（14-34）含量较低。A/CNK比值在1.10 ~ 1.28之间，表明花岗岩属于过铝质系列。此外，富铝矿物的存在（例如，白云母和石榴子石）表明它们是S型花岗岩。1.3 Ga锆石的εHf（t）值为负值至略正值（−9.28-3.1），并显示古老的两阶段模式年龄（TDM 2）（3.3-2.1 Ga）。花岗岩中的继承性锆石和1.3Ga锆石的Lu-Hf同位素组成与孔兹岩带东段济宁杂岩中的碎屑锆石的年龄一致。根据这些事实，我们推断本研究中的花岗岩是由济宁杂岩部分熔融形成的。华北克拉通北缘的基性岩墙（燕辽大火成岩省）和商都花岗岩强烈地反映了一个伸展环境，这与华北克拉通从哥伦比亚超大陆的裂解有关。地幔柱可能是断裂的主要驱动力，它应该为济宁杂岩的部分熔融提供了热量。
Mesoproterozoic (∼1.3 Ga) magmatism in the North China Craton (NCC) was characterized by diabase sills, while contemporary granitic magmatism was relatively rare, limiting our understanding of the NCC’s evolution during this period. In this manuscript, we report newly identified ∼1.3 Ga S–type granitic plutons in the Shangdu area, the western part of the northern NCC. Based on the results of geochemical, geochronological and zirconin–situLu–Hf isotope analyses, we discussed the petrogenesis, tectonic setting of the granitic plutons and the regime that drove the break–up of the NCC from the Columbia supercontinent. The zircon laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) U–Pb dating results indicate that these granites were emplaced at some time between 1315 ± 21 Ma and 1307 ± 32 Ma. Moreover, the geochemical results show that they have high contents of SiO2(75.34–76.97 wt%), Al2O3(12.90–13.61 wt%) and Na2O + K2O (6.21–8.31 wt%), but low MgO (0.09–0.25 wt%) and Mg#(14–34). The A/CNK ratios varied between 1.10 and 1.28, indicating that the granites belong to the peraluminous series. Furthermore, the existence of Al–rich minerals (e.g., muscovite and garnet) suggests that they are the S–type granites. The ∼1.3 Ga zircon display negative to slightly positive εHf(t) values (−9.28–3.1) and old two–stage model ages (TDM2) (3.3–2.1 Ga). The ages of the inherited zircon and Lu–Hf isotope compositions of the ∼1.3 Ga zircon in the granite are consistent with those of the detrital zircon from Jining complex, the eastern part of the Khondalite Belt. Based on these facts, we infer that the granites in this study derived from the partial melting of the Jining complex. The coeval mafic dykes (in the Yanliao large igneous province) and the Shangdu granite in the north margin of the NCC strongly suggest an extensional setting, which was related to the break–up of the NCC from the Columbia supercontinent. A mantle plume was likely the dominant driver of the break–up and it should have provided heat for the partial melting of Jining complex.