New field relations and U-Pb ages of detrital zircons from Middle Devonian-Upper Triassic sedimentary rocks in the South Tianshan constrain the time and style of terminal suturing between the Tarim Craton and the Yili-Central Tianshan arc. The variety of mélange blocks set within diagnostic thrust-imbricates demonstrates that basalts, limestones, cherts and sandstones belong to the Ocean Plate Stratigraphy (OPS) of an accreted oceanic plate. The imbricated OPS structure is further confirmed by our observation of lateral juxtaposition of Lower Carboniferous meta-sandstones and Upper Carboniferous sandstones. Detrital zircon ages from Middle Devonian to Lower-Middle Triassic rocks show no input from the Tarim Craton, but rather derivation from the Yili-Central Tianshan arc or from isolated seamounts/oceanic plateaus within the South Tianshan oceanic plate. The integrated field observations and sediment provenance indicate that these rocks belong to the South Tianshan accretionary complex. The Upper Triassic sandstones show a mixed provenance from the Tarim Craton and the Yili-Central Tianshan arc suggesting that the final subduction of the South Tianshan oceanic plate lasted until its terminal collision to the Tarim craton in the Late Triassic. Our work not only supports continuous northward subduction of the South Tianshan oceanic plate, but also indicates that the cryptic terminal suture between the Tarim Craton and the Yili-Central Tianshan arc is situated on the southern boundary of the South Tianshan accretionary complex, providing new constraints on the final amalgamation of the Altaid orogen. This multi-disciplinary study demonstrates an optimum means of unravelling the complex framework and tectonic evolution of an accretionary orogen.

中文翻译：

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塔里木克拉通与伊犁-中天山弧的末端缝合——从混杂-海洋板块地层、碎屑锆石年龄和南天山增生杂岩物源的洞察

南天山中泥盆统-上三叠统沉积岩碎屑锆石的新场关系和U-Pb年龄制约了塔里木克拉通与伊犁-中天山弧端缝合的时间和方式。诊断性逆冲叠瓦岩内设置的各种混杂岩块表明玄武岩、石灰岩、燧石和砂岩属于增生大洋板块的海洋板块地层 (OPS)。我们对下石炭统变质砂岩和上石炭统砂岩横向并置的观察进一步证实了叠瓦状 OPS 结构。从中泥盆世到中下三叠世岩石的碎屑锆石年龄显示没有来自塔里木克拉通的输入，而是源自伊犁-中天山弧或南天山大洋板块内孤立的海山/大洋高原。综合野外观测和沉积物源表明，这些岩石属于南天山增生杂岩。上三叠世砂岩显示出来自塔里木克拉通和伊犁-中天山弧的混合物源，表明南天山大洋板块的最后俯冲一直持续到晚三叠世与塔里木克拉通的最终碰撞。我们的工作不仅支持了南天山大洋板块持续向北俯冲，而且表明塔里木克拉通与伊犁-中天山弧之间的隐秘末端缝合线位于南天山增生杂岩的南边界，为阿尔泰造山带的最终合并提供了新的限制。这项多学科研究展示了一种解开增生造山带复杂框架和构造演化的最佳方法。