Seismic anisotropy provides insight into past episodes of lithospheric deformation and the orientations of strain in the underlying asthenosphere. The Greenland mantle has played host to a rich history of tectonic processes, including multiple orogenies and plume‐lithosphere interactions. This study presents new measurements of SKS splitting that reveal strong variations in fast polarization direction with back‐azimuth that are consistent across Greenland, including at stations where splitting measurements have not previously been reported. We compared observed fast polarization directions to the predictions of two‐layer models with olivine‐orthopyroxene anisotropy. The family of models that provides acceptable misfits at 95% confidence indicates an upper layer olivine a‐axis azimuth of 222–236°, a lower layer olivine a‐axis azimuth of 114–130°, and non‐zero a‐axis plunges. These models are consistent with an upper layer of lithospheric anisotropy due to Proterozoic and Archean orogenic fabrics, and a lower layer of anisotropy corresponding to either asthenospheric flow aligned approximately parallel to the direction of absolute plate motion and plunging due to lithospheric topography or dipping lithospheric structures created by episodes of paleo‐convergence.

中文翻译：

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格陵兰岛下的多层地震各向异性

地震各向异性可以洞悉岩石圈过去的变形以及底层软流圈中应变的方向。格陵兰地幔为构造过程的丰富历史提供了宿主，其中包括多个造山带和羽石圈之间的相互作用。这项研究提出了新的SKS分裂测量结果，揭示了在快速极化方向上具有强烈反向变化的反向方位角，这在格陵兰岛上是一致的，包括以前从未报道过分裂测量的站点。我们将观察到的快速极化方向与橄榄石-邻-邻二甲苯各向异性的两层模型的预测结果进行了比较。在95％置信度下提供可接受的失配的模型系列表明，上层橄榄石a轴方位角为222–236°，下层橄榄石a轴方位角为114–130°，和非零轴突降。这些模型与由于元古代和太古代造山构造引起的岩石圈各向异性的上层，以及与软流圈的流动相对应的各向异性的下层相一致，该流动层大致平行于绝对板块运动的方向，并由于岩石圈的地形或岩石圈的倾覆而下沉。由古收敛事件创建。