中国地质大学（北京）邓军团队的最新研究报道了，岩石圈地幔作为大陆边缘造山型金矿床的金属储存库来自汞同位素证的证据。2024年3月1日，国际知名学术期刊《地质学》发表了这一成果。

研究提供了来自胶东金矿省6个主要金矿区的一组黄铁矿颗粒、原生金和煌斑岩的汞同位素数据。在地幔Δ¹⁹⁹Hg值的不确定度范围内，这些样品主要产生接近于零的Δ¹⁹⁹Hg(0‰±0.1‰)。研究结果提供了新的证据，证明SCL主要控制着胶东金矿床的汞平衡，表明SCLM充当了地壳质量无关分馏汞特征的缓冲区和金及挥发物的储存库。因此，在板块俯冲过程中，金和挥发物被回收并储存在SCLM中，随后在挤压构造的隆升和松弛过程中从地幔中释放出来。

据了解，目前许多学者认为，在活动大陆边缘，由于金和挥发物可能在板块俯冲过程中被引入到次大陆岩石圈地幔（SCLM）中，SCLM在活动大陆边缘的造山型金矿床的形成中起着重要作用。华北地块内巨大的白垩系胶东金矿区赋存于无地体增生的聚合边缘环境中，排除了公认的造山型金矿的金属和流体源致密储层—活动造山带的变质上地壳。因此，这些含金成矿流体要么来自富集的SCLM，要么直接来自俯冲的大洋板块，释放于高级太古宙克拉通岩层下方。汞(Hg)同位素可以对同位素不同的储层进行识别并区分两种可能性。

附：英文原文

Title: Lithospheric mantle as a metal storage reservoir for orogenic gold deposits in active continental margins: Evidence from Hg isotopes

Author: Jing-Yuan Zhang, Kun-Feng Qiu, Runsheng Yin, Zheng-Yu Long, Yue-Chuan Feng, Hao-Cheng Yu, Zi-Yue Gao, Jun Deng

Issue&Volume: 2024-03-01

Abstract: The subcontinental lithospheric mantle (SCLM) is now suggested by many workers to play a role in the formation of orogenic gold deposits in active continental margins, given that the gold and volatiles may be introduced into the SCLM during plate subduction. The giant Cretaceous Jiaodong gold province within the North China block occurs in a convergent margin setting where there is no terrane accretion, thus eliminating from consideration the commonly accepted metal and fluid source reservoir for orogenic gold—the metamorphosed upper crust of an active orogenic belt. Thus, the auriferous fluids were released below the high-grade Archean cratonic rocks from either enriched SCLM or directly from the subducted oceanic slab. Mercury (Hg) isotopes allow fingerprinting of isotopically distinct reservoirs, discriminating between the two possibilities. We present Hg isotope data for a set of pyrite grains, native gold, and lamprophyres from six main gold districts in the Jiaodong gold province. These samples dominantly yielded near-zero Δ¹⁹⁹Hg (0‰ ± 0.1‰), within uncertainty of the mantle Δ¹⁹⁹Hg value. The results provide novel evidence that the SCLM predominantly controlled the Hg budget of the Jiaodong gold deposits, implying that the SCLM acted as a buffer for the crustal mass-independent fractionation Hg signatures and a storage reservoir for gold and volatiles. Consequently, during slab subduction, gold and volatiles were recycled and stored within the SCLM and were later released from the mantle during uplift and relaxation of compressional tectonics.

DOI: 10.1130/G51871.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G51871.1/635784/Lithospheric-mantle-as-a-metal-storage-reservoirredirectedFrom=fulltext