Hawaiian volcanoes belong to two geographically and geochemically distinct trends, the Loa and Kea trends. The cause of this dichotomy is still strongly debated. One of the prevailing hypotheses is that the two trends originate in the deep mantle where the Hawaiian mantle plume straddles two geophysically and geochemically distinct domains at the core‐mantle boundary (CMB). New high‐precision multi‐isotopic (Pb, Hf, Nd, and Sr) compositions of lavas from three key volcanoes, Lō‘ihi, Kohala, and Haleakalā, show transitional signatures between Loa and Kea compositions that call into question the degree of physical independence between the two trends. Statistical analysis of multi‐collector inductively coupled plasma mass spectrometer or triple‐spike Pb (n > 800) and Sr, Nd, and Hf data (n > 400) for shield tholeiites from the entire Hawaiian Islands (<5.5 Ma) identifies six unique geochemical groups, and for the first time, documents large‐scale heterogeneities in the Kea trend. The spatial orientation of the six geochemical groups shows that the bilateral zonation of the plume source at the CMB is gradational, and that the Hawaiian mantle plume periodically entrains large‐scale ephemeral geochemical heterogeneities on million‐year, regional timescales. These geochemical heterogeneities are stretched vertically during transit of the plume to the surface and are observed in the lavas from the Hawaiian Islands. These results provide evidence that the large low shear velocity province in the deep Pacific is thermochemical and highly heterogeneous.

中文翻译：

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通过夏威夷玄武岩地球化学的统计分析解析地球深层地幔的精细尺度结构

夏威夷火山属于两个在地理和地球化学上不同的趋势，Loa和Kea趋势。这种二分法的原因仍在激烈辩论中。普遍的假设之一是这两种趋势起源于深地幔，夏威夷地幔羽跨越了地幔边界（CMB）的两个地球物理和地球化学不同的区域。新的高精度多同位素（Pb，Hf，Nd和Sr）熔岩来自Lō'ihi，Kohala和Haleakalā这三个主要火山，显示出Loa和Kea组分之间的过渡特征，这质疑了物理程度两种趋势之间的独立性。多收集器电感耦合等离子体质谱仪或三峰Pb（n  > 800）和Sr，Nd和Hf数据（n 大于400）的来自整个夏威夷群岛（<5.5 Ma）的盾构孔雀石确定了六个独特的地球化学组，并且首次记录了Kea趋势中的大规模异质性。六个地球化学组的空间方向表明，CMB羽流源的双边分区是渐变的，夏威夷地幔羽周期性地在百万年的区域时间尺度上夹带了大规模的短暂地球化学异质性。这些地球化学异质性在羽流向地表转移的过程中被垂直拉伸，并在夏威夷群岛的熔岩中观察到。这些结果提供了证据，表明太平洋深部的低剪切速度大省是热化学性质且高度非均质的。