The initial stage of Rodinia supercontinent break-up occurred at about 750 Ma. It preceded formation of the Irkutsk and Franklin large igneous provinces (LIPs) at 712 ± 2 to 739 ± 8 Ma. These LIPs were emplaced within the formerly connected Laurentian and Siberian cratons. The Kingash massif is located in the Precambrian Kan terrane in direct contact with the Siberian Craton at its southwestern boundary. It has been linked to an important suite of mafic–ultramafic intrusions that border the southern margin of the Siberian craton, and that have been inferred to belong to the Irkutsk LIP. The massif is also significant, because it hosts platinum group element (PGE)–Cu–Ni-rich mineralization and is the only large deposit in the region. However, despite numerous dating attempts, the age of the massif had not been resolved. A significant difficulty is post-magmatic recrystallization at amphibolite facies that affected the rocks of the massif. In this study we used U–Pb dating of zircon, titanite and apatite from rocks of the Kingash massif and cross-cutting granite and monzonite veins. The oldest igneous zircon grain of the Kingash massif analysed by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) yields an age of c. 750 Ma, taken as a tentative age of magmatism. Dating of multiple grains of metamorphic zircon by chemical abrasion isotope dilution thermal ionization mass spectrometry yielded 564·8 ± 2·2 Ma, which is in agreement with LA-ICP-MS titanite ages of 557 ± 19, 565 ± 35 and 551 ± 17 Ma. Apatite of two different samples showed ages of 496·4 ± 7·9 and 497·0 ± 1·8 Ma (LA-ICP-MS), which are interpreted as the time when the terrane cooled below the closure temperature of apatite. Using our new data we suggest that at the time of the Irkutsk–Franklin LIP event the Kan terrane was a part of Rodinia, then it separated from either Siberia or Laurentia during the break-up of Rodinia and finally collided with Siberia at 560 Ma, the time of regional amphibole-facies metamorphism.

中文翻译：

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西伯利亚 Kan Terrane 的 Kingash Mafic-Ultramafic 地块的磷灰石、钛矿和锆石的 U-Pb 测年：从罗迪尼亚分裂到与西伯利亚克拉通重聚

Rodinia 超大陆分裂的初始阶段发生在 750 Ma 左右。它早于伊尔库茨克和富兰克林大火成岩省（LIP）的形成，时间为 712 ± 2 至 739 ± 8 Ma。这些 LIP 位于以前相连的劳伦克拉通和西伯利亚克拉通内。Kingash地块位于前寒武纪坎地体中，在其西南边界与西伯利亚克拉通直接接触。它与西伯利亚克拉通南缘接壤的一组重要的镁铁质-超镁铁质侵入体有关，据推测属于伊尔库茨克 LIP。该地块也很重要，因为它拥有富含铂族元素 (PGE)-Cu-Ni 的矿化，并且是该地区唯一的大型矿床。然而，尽管进行了多次约会尝试，地块的年龄仍未确定。一个显着的困难是影响地块岩石的角闪岩相的岩浆后重结晶。在这项研究中，我们使用了来自 Kingash 地块岩石和横切花岗岩和二长岩脉的锆石、榍石和磷灰石的 U-Pb 测年。通过激光烧蚀电感耦合等离子体质谱法 (LA-ICP-MS) 分析的 Kingash 地块中最古老的火成锆石颗粒产生的年龄为 c。750 Ma，为岩浆活动的暂定年代。通过化学磨损同位素稀释热电离质谱法对多颗变质锆石进行测年，得到 564·8 ± 2·2 Ma，这与 LA-ICP-MS 钛矿年龄 557 ± 19、565 ± 35 和 551 ± 17 一致嘛。两种不同样品的磷灰石年龄分别为 496·4 ± 7·9 和 497·0 ± 1·8 Ma (LA-ICP-MS)，这被解释为地体冷却到磷灰石闭合温度以下的时间。使用我们的新数据，我们建议在伊尔库茨克-富兰克林 LIP 事件发生时，坎地体是罗迪尼亚的一部分，然后在罗迪尼亚分裂期间它与西伯利亚或劳伦提亚分离，最后在 560 Ma 与西伯利亚相撞，区域闪石相变质作用时间。