Research press release


Nature Geoscience

Yellowstone’s deep-mantle plumbing



Peter NelsonとStephen Grandは、アーススコープ(米国の大規模地球観測プログラム)のUSArray計画により収集された地震学的データを用いて、北米下のマントルの画像を取得した。Nelsonたちはマントル内に、地震波の伝達が周囲より遅い(すなわち、異常に高温の物質の存在を示唆している)、傾斜した細長い領域を同定した。この領域はマントル内でほぼ連続しており、メキシコの下の中心核-マントル境界に根があり、そこから北東方向にイエローストーン国立公園まで延びている。


The volcanic activity at Yellowstone National Park in the western United States might be driven by a mantle plume rising from the core-mantle boundary deep in the Earth, reports a study published online this week in Nature Geoscience.

Whether or not a mantle plume - a column of potentially warm, upwelling material - might lie beneath Yellowstone National Park has been hotly debated for decades. Mantle plumes are themselves contentious because seismic images of the Earth’s interior largely failed to unambiguously identify plume-like features that trace all the way down to the deep mantle.

Peter Nelson and Stephen Grand use seismic data collected by EarthScope’s USArray project to image the mantle beneath North America. The authors identify a long, thin, sloping zone within the mantle through which seismic waves travel more slowly - and which may indicate the presence of unusually warm material. The zone extends almost continuously through the mantle, rooted in the core-mantle boundary beneath Mexico and running north-eastwards up to Yellowstone National Park.

This finding implies that the volcanic activity at Yellowstone, which includes hydrothermal springs and explosive geysers like the famous ‘Old Faithful’, as well as super-eruptions in the geologic past, could all ultimately be driven by this deep-mantle plume rising up from above the Earth’s core.

doi: 10.1038/s41561-018-0075-y


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