U-Pb isotopy data of deformed samples from the Yushu mélange, western Jinsha Suture

Deformed samples from the Yushu mélange, in the western Jinsha Suture, have been dated by U-Pb isotopy on zircons. This dataset presents U-Pb isotopy data obtained for these samples. The rock sample was crushed using standard procedures. The zircon grains were handpicked from the 80-200 micrometer non-magnetic fraction, placed on epoxy mounts and polished. Back-scattered electron images of the grains were acquired with a Hitachi S2500 Scanning Electron Microprobe at the Institut des Sciences de la Terre (ISTerre) of Grenoble (France). U-Pb zircon analyses were performed by in-situ LA-ICP-MS, using an ESI NWR193UC excimer laser coupled to a quadrupole Agilent 7700x ICP-MS at the GeOHeLiS analytical Platform (OSUR, Univ. Rennes). The diameter of the ablation spots varies from 20 to 30 µm, depending on the grain size. The repetition rate of the ablation was 3 Hz. Data were corrected for U-Pb and Th-Pb fractionation and for mass bias by repeated measurements of the standard GJ-1 (Jackson et al., 2004). Accuracy was monitored by analyses of the standard Plešovice (337.13 ± 0.37 Ma, Sláma et al., 2008), which produced a concordia age of 337.1 ± 2.1 Ma (N=18; MSWD=0.65) during the course of the analyses. Data reduction was carried out using the software Iolite v4 (Paton et al., 2010, 2011). The concordia ages and diagrams were generated using IsoplotR (Vermeesch, 2018). The full instrumental and analytical conditions can be found in Table "Operating conditions for the LA-ICP-MS equipment" and in Nosenzo et al. (2022).

采自金沙江缝合带西段玉树混杂岩的变形样品，已通过锆石U-Pb同位素法完成年代学测定。本数据集收录该批样品的U-Pb同位素测试数据。岩石样品按照标准流程进行粉碎。锆石颗粒从80~200微米的非磁性组分中手工挑选，固定于环氧树脂靶并经抛光处理。锆石颗粒的背散射电子图像由法国格勒诺布尔地球科学研究所（Institut des Sciences de la Terre, ISTerre）的Hitachi S2500型扫描电子探针采集获得。锆石U-Pb原位分析采用激光剥蚀电感耦合等离子体质谱（LA-ICP-MS）完成，实验依托雷恩大学OSUR下属的GeOHeLiS分析平台开展，使用ESI NWR193UC准分子激光器与安捷伦7700x四极杆ICP-MS联用系统。剥蚀斑束直径依据锆石颗粒大小调整，范围为20~30微米，剥蚀重复频率为3赫兹。通过重复测定标准参考物质GJ-1（Jackson等，2004），对U-Pb、Th-Pb分馏效应及质量歧视进行校正。本次分析采用Plešovice标准锆石（参考年龄337.13 ± 0.37 Ma，Sláma等，2008）监控分析准确度，该标准锆石的实测谐和年龄为337.1 ± 2.1 Ma（N=18；MSWD=0.65）。数据处理采用Iolite v4软件完成（Paton等，2010、2011）。谐和年龄及相关图解均通过IsoplotR软件生成（Vermeesch，2018）。完整的仪器及分析条件详见表"Operating conditions for the LA-ICP-MS equipment"及Nosenzo等（2022）的研究成果。