Cratons are Earth’s ancient continental land masses that remain stable for billions of years. The mantle roots of cratons are renowned as being long-lived, stable features of Earth’s continents, but there is also evidence of their disruption in the recent^1,2,3,4,5,6 and more distant^7,8,9 past. Despite periods of lithospheric thinning during the Proterozoic and Phanerozoic eons, the lithosphere beneath many cratons seems to always ‘heal’, returning to a thickness of 150 to 200 kilometres^10,11,12; similar lithospheric thicknesses are thought to have existed since Archaean times^3,13,14,15. Although numerous studies have focused on the mechanism for lithospheric destruction^{2,5,13,16,17,18,19}, the mechanisms that recratonize the lithosphere beneath cratons and thus sustain them are not well understood. Here we study kimberlite-borne mantle xenoliths and seismology across a transect of the cratonic lithosphere of Arctic Canada, which includes a region affected by the Mackenzie plume event 1.27 billion years ago²⁰. We demonstrate the important role of plume upwelling in the destruction and recratonization of roughly 200-kilometre-thick cratonic lithospheric mantle in the northern portion of the Slave craton. Using numerical modelling, we show how new, buoyant melt residues produced by the Mackenzie plume event are captured in a region of thinned lithosphere between two thick cratonic blocks. Our results identify a process by which cratons heal and return to their original lithospheric thickness after substantial disruption of their roots. This process may be widespread in the history of cratons and may contribute to how cratonic mantle becomes a patchwork of mantle peridotites of different age and origin.

克拉通是地球上古老的大陆陆块，数十亿年保持稳定。克拉通的地幔根部被认为是地球大陆的长寿、稳定的特征，但也有证据表明它们在最近的^1,2,3,4,5,6和更远的^7,8,9过去. 尽管在元古代和显生宙期间岩石圈变薄，但许多克拉通下方的岩石圈似乎总是“愈合”，厚度恢复到 150 到 200 公里^10,11,12；类似的岩石圈厚度被认为自太古代^3,13,14,15以来就存在。尽管许多研究都集中在岩石圈破坏的机制上^{2,5,13 ,​​16,17,18,19}，克拉通下的岩石圈再克拉通并因此维持它们的机制尚不清楚。在这里，我们研究金伯利岩携带的地幔捕虏体和横跨加拿大北极克拉通岩石圈横断面的地震学，其中包括 12.7 亿年前受麦肯齐羽流事件影响的地区²⁰. 我们证明了羽流上升流在斯拉夫克拉通北部约 200 公里厚的克拉通岩石圈地幔的破坏和再克拉通化中的重要作用。使用数值模型，我们展示了 Mackenzie 羽流事件产生的新的、有浮力的熔融残余物是如何在两个厚克拉通块之间的变薄岩石圈区域中捕获的。我们的研究结果确定了克拉通在其根部大量破坏后愈合并恢复其原始岩石圈厚度的过程。这个过程可能在克拉通的历史上很普遍，并且可能有助于克拉通地幔如何成为不同年龄和起源的地幔橄榄岩的拼凑。