Montelli Raffaella, Nolet Guust, Dahlen F A, Masters Guy, Engdahl E Robert, Hung Shu-Huei
Department of Geosciences, Princeton University, Princeton, NJ 08544, USA.
Science. 2004 Jan 16;303(5656):338-43. doi: 10.1126/science.1092485. Epub 2003 Dec 4.
We present tomographic evidence for the existence of deep-mantle thermal convection plumes. P-wave velocity images show at least six well-resolved plumes that extend into the lowermost mantle: Ascension, Azores, Canary, Easter, Samoa, and Tahiti. Other less well-resolved plumes, including Hawaii, may also reach the lowermost mantle. We also see several plumes that are mostly confined to the upper mantle, suggesting that convection may be partially separated into two depth regimes. All of the observed plumes have diameters of several hundred kilometers, indicating that plumes convey a substantial fraction of the internal heat escaping from Earth.
我们展示了深部地幔热对流柱存在的层析成像证据。P波速度图像显示至少有六个分辨率良好的对流柱延伸至下地幔底部:阿森松岛、亚速尔群岛、加那利群岛、复活节岛、萨摩亚群岛和塔希提岛。其他分辨率稍差的对流柱,包括夏威夷,可能也延伸至下地幔底部。我们还看到一些主要局限于上地幔的对流柱,这表明对流可能部分地被分隔为两个深度区域。所有观测到的对流柱直径都有数百公里,这表明对流柱传输了从地球逃逸的相当一部分内热。