近日，中国地质大学（武汉）陈春飞团队在研究碳酸盐熔体的地质过程与矿产形成中取得新进展。相关论文于2025年1月8日发表在《自然》杂志上。

据研究人员介绍，克拉通地壳中含有丰富的金、铜和稀土等金属矿床，并被富含挥发物碳、硫和水的厚地幔岩石圈所覆盖。虽然挥发物被认为是成矿作用的关键成分，但它们在克拉通岩石圈地幔中的分布方式和位置，以及它们在金属初始富集中的作用，还没有得到充分的探索。

研究人员对全球克拉通橄榄岩的硫和铜含量进行了收集，在克拉通边缘160-190km的深度确定了富含硫化物和富含铜的大陆根。新的高压实验表明，源自软流圈的碳酸硅酸盐熔体，在与岩石圈橄榄岩的反应过程中会失去硅酸盐成分，演变成碳酸盐岩熔体，并集中在克拉通边缘。

在此过程中，随着熔体SiO₂含量的降低，硫在熔体中的溶解度大幅降低，迫使硫化物沉淀，并在地幔岩石圈底部形成富硫化物的大陆根。碳酸化熔体向克拉通边缘的迁移，为那里的大陆根补充了硫，这解释了岩浆金属矿床与靠近克拉通边缘的碳酸盐岩的共存。这些发现突出了碳酸盐熔体在成矿作用中的重要作用，为金属矿勘查提供了潜在的平台。

附：英文原文

Title: Sulfide-rich continental roots at cratonic margins formed by carbonated melts

Author: Chen, Chunfei, Frster, Michael W., Shcheka, Svyatoslav S., Ezad, Isra S., Shea, Joshua J., Liu, Yongsheng, Jacob, Dorrit E., Foley, Stephen F.

Issue&Volume: 2025-01-08

Abstract: The cratonic crust contains abundant mineral deposits of metals such as gold, copper and rare earths and is underlain by a thick mantle lithosphere rich in the volatiles carbon, sulfur and water. Although volatiles are known to be key components in metallogenesis9, how and where they are distributed in the cratonic lithosphere mantle and their role in the initial enrichment of metals have not been sufficiently explored. Here we compile sulfur and copper contents of global cratonic peridotites, identifying sulfide-rich and copper-rich continental roots at depths of 160–190km at cratonic margins. Our new high-pressure experiments show that carbonated silicate melts originating from the asthenosphere lose silicate components during reaction with lithospheric peridotite, evolving to carbonatite melts that become concentrated at cratonic margins. Sulfur solubility in melts substantially decreases as the SiO₂ content of melts decreases during this process, forcing sulfide precipitation and the formation of sulfide-rich continental roots at the base of the mantle lithosphere. The migration of carbonated melts towards cratonic margins replenishes the continental roots there with sulfur, explaining the co-location of magmatic metal deposits with carbonatites close to cratonic margins. These findings highlight the notable role of carbonated melts in metallogenesis and provide a potential platform for metal ore exploration.

DOI: 10.1038/s41586-024-08316-w

Source: https://www.nature.com/articles/s41586-024-08316-w