The Yellowstone hotspot, located in North America, is an intraplate source of magmatism the cause of which is hotly debated. Some argue that a deep mantle plume sourced at the base of the mantle supplies the heat beneath Yellowstone, whereas others claim shallower subduction or lithospheric-related processes can explain the anomalous magmatism. Here we present a shear wave tomography model for the deep mantle beneath the western United States that was made using the travel times of core waves recorded by the dense USArray seismic network. The model reveals a single narrow, cylindrically shaped slow anomaly, approximately 350 km in diameter that we interpret as a whole-mantle plume. The anomaly is tilted to the northeast and extends from the core–mantle boundary to the surficial position of the Yellowstone hotspot. The structure gradually decreases in strength from the deepest mantle towards the surface and if it is purely a thermal anomaly this implies an initial excess temperature of 650 to 850 °C. Our results strongly support a deep origin for the Yellowstone hotspot, and also provide evidence for the existence of thin thermal mantle plumes that are currently beyond the resolution of global tomography models.

位于北美的黄石热点是板块内岩浆活动的来源，其成因受到了激烈的争论。一些人认为，来自地幔底部的深层地幔柱为黄石下面提供了热量，而另一些人则认为，较浅的俯冲作用或与岩石圈有关的过程可以解释异常的岩浆作用。在这里，我们介绍了美国西部深部地幔的剪切波层析成像模型，该模型是使用密集的USArray地震网络记录的核心波的传播时间建立的。该模型揭示了一个狭窄的圆柱形缓慢异常，直径约350 km，我们将其解释为全幔柱羽。该异常向东北倾斜，并从岩心-地幔边界延伸到黄石热点的表层位置。该结构的强度从最深的地幔到表面逐渐降低，如果纯粹是热异常，则意味着初始温度超过650至850°C。我们的结果有力地支持了黄石热点的深层渊源，也为存在薄的热幔柱羽流提供了证据，而目前这些柱幔流柱尚未超出全球层析成像模型的分辨率。