近日，中国科学院广州地理化学研究所何宏平团队研究了熔体流动对大洋上地幔岩性和地球化学非均质性的控制。相关论文发表在2026年3月10日出版的《国家科学评论》杂志上。

地球的上地幔在岩石学和地球化学上具有非均质性，深海橄榄岩与古洋幔橄榄岩的组成变化均证实了这一点。然而，由于这些橄榄岩之间缺乏空间关系的约束，阻碍了对地幔多样性成因及其地球动力学过程的深入解释。

研究组首次对西藏蛇绿岩地幔序列的约1300米新鲜钻探岩芯开展岩石学和地球化学研究。该地幔柱剖面呈现出由二辉橄榄岩、方辉橄榄岩和纯橄岩构成的重复"层状"结构，具有显著的非均质性。其中二辉橄榄岩和方辉橄榄岩分别经历过10-15%和15-25%的熔体抽取，这种熔损程度无法仅通过常规部分熔融模型实现，还需要软流圈地幔中发生熔体-橄榄岩相互作用。该研究为揭示大洋上地幔顶部的岩石学结构与化学成分提供了高分辨率剖面，并建立了软流圈内的熔体运移模型，该模型可解释大洋中脊和俯冲带上覆地幔岩石的岩性多样性。

附：英文原文

Title: Melt flow control on lithological and geochemical heterogeneity of the oceanic upper mantle

Author: Rui, Hui-Chao, Doucet, Luc S, Lissenberg, C Johan, Lian, Dong-Yang, Li, Jie, Cai, Peng-Jie, Lai, Sheng-Min, Zhu, Jian-Xi, He, Hong-Ping, Yang, Jing-Sui

Issue&Volume: 2026-03-10

Abstract: The Earth’s upper mantle is heterogeneous in lithology and geochemistry, as demonstrated by variations in both abyssal peridotites and fossil oceanic mantle peridotites. The scarcity of spatial relationships between these peridotites, however, hinders further interpretation of the origin of mantle diversity as well as corresponding geodynamic processes. Here, we report the petrographic and chemical data of peridotites from the first fresh drill core (~1300 m) across a Tibetan ophiolitic mantle sequence. This mantle column shows a primarily heterogeneous lithological structure consisting of repetitive ‘layered’ lherzolite, harzburgite, and dunite. Lherzolite and harzburgite have experienced 10–15% and 15–25% melt depletion, respectively. Such depletion cannot be generated by conventional partial melting models alone, but also requires melt-peridotite interaction in the asthenospheric mantle. Our work provides a high-resolution snapshot of the lithological structure and chemistry of the uppermost oceanic mantle and offers a melt flow model within the asthenosphere to explain the lithological variability of mantle rocks found in both mid-ocean ridges and supra-subduction zones.

DOI: 10.1093/nsr/nwag130

Source: https://dx.doi.org/10.1093/nsr/nwag130