The Wenjiaping granite, as one of the few Late Jurassic granites in the Songpan–Garzê fold belt (SGFB), can provide an important clue for comprehensively recognizing the tectonic evolution and mineralization of this belt. In this contribution, we present new age and geochemical data for this pluton to better constrain its petrogenesis and discuss the tectonic and metallogenic implications. LA-ICP-MS zircon U–Pb dating shows that the Wenjiaping pluton was emplaced at ~159 Ma. The granite contains minor amphibole, and exhibits slightly peraluminous characteristics (A/CNK = 1.03–1.10) and lower initial Sr–Pb isotope ratios than those of the Liwu Group, which excludes the possibility that the Wenjiaping granite was derived from partial melting of the metasedimentary rock-dominated Liwu Group as previously suggested. Significantly, high Sr/Y (40.93–54.30), La_N/Yb_N (39.64–56.64), and K₂O/NaO (0.77–1.11) ratios, low MgO (0.47%–0.86%) and Cr (25.1–41.3 ppm) contents, and relatively enriched Sr–Nd–Pb–Hf isotope compositions of the Wenjiaping granite are comparable to those of the Late Triassic adakitic rocks in the SGFB, indicating that they probably share a similar source. Combined with previous researches, we propose that large-scale detachment of the Jianglang dome caused by post-collisional lithospheric extension in the SGFB-induced decompressional partial melting of the Precambrian basement rocks can account for the generation of the Late Jurassic Wenjiaping pluton. In addition, our results also suggest that the Wenjiaping pluton probably cannot supply abundant metal elements for the Liwu-type Cu-polymetallic deposits in the Jianglang dome, SGFB.

中文翻译：

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晚侏罗世温家坪高Sr/Y花岗岩：松潘—甘孜褶皱带岩石圈伸展触发的前寒武纪基底岩石部分熔融的产物

温家坪花岗岩作为松潘—甘孜褶皱带（SGFB）少数晚侏罗世花岗岩之一，可为全面认识该带的构造演化和成矿作用提供重要线索。在这篇文章中，我们提供了该岩体的新年龄和地球化学数据，以更好地限制其成因并讨论构造和成矿影响。LA-ICP-MS 锆石 U-Pb 测年表明温家坪岩体在~159 Ma 就位。花岗岩含有少量闪石，具有轻微的过铝质特征（A/CNK = 1.03~1.10），初始Sr-Pb同位素比低于立雾群，排除了温家坪花岗岩为部分熔融形成的可能性。如前所述，以变质沉积岩为主的立雾群。值得注意的是，高 Sr/Y (40.93–54._N /Yb _N (39.64–56.64) 和 K ₂温家坪花岗岩的 O/NaO（0.77-1.11）比、低 MgO（0.47%-0.86%）和 Cr（25.1-41.3 ppm）含量以及相对富集的 Sr-Nd-Pb-Hf 同位素组成与SGFB 中的晚三叠世埃达克质岩石，表明它们可能具有相似的来源。结合前人的研究，我们提出，在SGFB诱导的前寒武纪基底岩石减压部分熔融中，碰撞后岩石圈伸展引起的江浪穹顶的大规模拆离可以解释晚侏罗世温家坪岩体的形成。此外，我们的研究结果还表明，温家坪岩体可能无法为SGFB江朗穹窿立屋型铜多金属矿床提供丰富的金属元素。