Seismic Evidence of Mid‐Mantle Water Transport Beneath the Yellowstone Region
Seismic Evidence of Mid‐Mantle Water Transport Beneath the Yellowstone Region
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DOI：
10.1029/2021gl095838
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发表时间：
2021-10
影响因子：
5.2
通讯作者：
W. Frazer;Jeffrey Park
中科院分区：
文献类型：
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作者：
W. Frazer;Jeffrey Park
地球地幔过渡带（MTZ）是一个可能的全球性水库，并可能负责长期（约100 Ma）的海洋质量调节。MTZ矿物中的水容量估计为100%，远远大于周围地幔的岩石。当富含水的物质从MTZ中排出时，会发生部分熔融，从而使地震接收器功能（RF）可检测到的地震速度急剧降低。我们估计RF的MTZ下黄石地区使用地震记录的地球镜移动式阵列的200个站。我们在MTZ上方和下方发现了许多LVZ，这与水合MTZ岩石相变为具有低水容量的上地幔和下地幔矿物组合时的水释放一致。LVZ的位置与由Farallon板片碎片的下降和深深扎根的黄石羽状物的上升引起的中地幔流一致，如地震层析成像所示。
Earth's mantle transition zone (MTZ) is a possible global water reservoir and may be responsible for long‐term (∼100 Ma) ocean‐mass regulation. Estimates of water capacities in MTZ minerals are ∼1 wt%, far greater than that of rocks of the surrounding mantle. When water‐rich material is displaced from the MTZ, partial melting occurs, generating a sharp reduction in seismic velocities detectable with seismic receiver functions (RFs). We estimated RFs for the MTZ beneath the Yellowstone region using earthquakes recorded by ∼200 stations of the Earthscope Transportable Array. We found many LVZs both above and below the MTZ, consistent with water release upon phase transformation of hydrated MTZ rock into upper‐ and lower‐mantle mineral assemblages with low water capacities. The locations of LVZs are consistent with mid‐mantle flow induced by descent of a Farallon‐slab fragment and ascent of the deeply rooted Yellowstone plume as imaged by seismic tomography.