New 3D multi‐azimuthal receiver function analysis identified four regional seismic discontinuities dipping at 7–13° within the mantle of the Superior craton of North America; most are discordant to known major upper crustal structures. Widely observed crustal‐scale structures with near‐vertical axial planes striking east‐west indicate that the most recent and dominant phase of folding and horizontal shortening strain occurred during the Kenoran (D2) crustal deformation concurrent with Au‐mineralization and peak metamorphism at 2.72–2.66 Ga. Two mantle discontinuities strike 065° and 249°, dipping to the southeast and northwest, respectively. These strikes roughly parallel the northern margin of the Superior craton and some intra‐cratonic features such as the axis of the Quetico Basin. Two discontinuities strike 355° and 187°, dipping to the east and west, respectively, and parallel to the western margin of the craton. Our new observations reveal neither moderately dipping, east‐west striking discontinuities nor coherent eclogitic layers characteristic of modern plate tectonic subduction zones. Prominent east‐ and west‐dipping mantle structures relate best to a Paleoproterozoic (Trans‐Hudson) deformation, which is rarely observed in the crust. A new analysis of mantle xenoliths and xenocrysts indicates that carbonatitic metasomatism predominates above some discontinuities where strongly localized conductivity occurs whereas kimberlitic metasomatism predominates below the discontinuities in the broadly conductive mantle.

中文翻译：

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北美上克拉顿内地幔岩石圈结构的多学科建模

新的3D多方位接收器功能分析确定了北美上克拉通地幔内7-13°倾角的四个区域地震不连续性。大多数与已知的主要上地壳结构不一致。广泛观察到的地壳尺度结构具有近乎垂直的轴向东西走向，表明在Kenoran（D2）地壳变形，金矿化和峰变质在2.72– 2.66 Ga。两个地幔间断点分别到达065°和249°，分别向东南和西北倾斜。这些走向大致平行于上克拉通的北缘和某些克拉通内部特征，例如奎蒂科盆地的轴线。两个不连续点分别指向355°和187°，分别向东和向西倾斜，并与克拉通的西边缘平行。我们的新观测结果既没有揭示出现代板块构造俯冲带特有的中等倾角，东西向的不连续性，也没有相干的火山岩层。突出的东西向的地幔结构与古元古代（Trans-Hudson）变形最相关，而在地壳中很少观察到这种变形。对地幔中的异岩和异晶的新分析表明，碳酸盐岩交代作用在某些不连续面之上占主导地位，在这些不连续面中发生强烈的局部电导率，而金伯利岩交界作用则主要在宽导电性地幔的不连续面之下。现代板块构造俯冲带的东西走向不连续或连贯的片状地层。突出的东西向的地幔结构与古元古代（Trans-Hudson）变形最相关，而在地壳中很少观察到这种变形。对地幔中的异岩和异晶的新分析表明，碳酸盐岩交代作用在某些不连续面之上占主导地位，在这些不连续面中发生强烈的局部电导率，而金伯利岩交界作用则主要在宽导电性地幔的不连续面之下。现代板块构造俯冲带的东西走向不连续或连贯的片状地层。突出的东西向的地幔结构与古元古代（Trans-Hudson）变形最相关，而在地壳中很少观察到这种变形。对地幔中的异岩和异晶的新分析表明，碳酸盐岩交代作用在某些不连续面之上占主导地位，在这些不连续面中发生强烈的局部电导率，而金伯利岩交代作用则主要在宽导电性地幔之下的不连续面之下。