近日，南非威特沃特斯兰德大学‘Mabatho Mapiloko团队的最新研究，揭示了古元古代最古老的海相硫酸盐蒸发岩对Bushveld杂岩带下部成矿作用的贡献。相关论文于2025年2月4日发表在《地质学》杂志上。

研究显示，Uitloop带下部侵入体的高镁岩浆所含的幔源硫不足，无法达到成矿所需的硫化物饱和度。当岩浆在大氧化期（GOE）之前和期间通过沉积地层上升时吸收硫时，硫化物达到饱和。Uitloop岩浆硫化物富集³⁴S，缺乏或表现出较小的、与质量无关的硫同位素分异，而太古代沉积下盘岩石硫化物则表现出太古代式的多硫同位素共变。

研究人员认为，早古元古代上Duitschland组硫酸盐蒸发岩的同化作用，与GOE早期依赖质量分异的海水硫酸盐储层的向内生长相对应，导致硫化物饱和并形成Cu-Ni-PGE型硫化物矿床。研究结果强调，GOE不仅改变了大气和海洋的氧化态，改变了沉积型矿床的类型，还形成了沉积型硫酸盐储层，为岩浆矿床提供了丰富的硫源。

据研究人员介绍，在过去的二十年中，多硫同位素系统学作为一种区分硫同位素特征的工具越来越受到重视，这对勘探目标具有重要意义。地壳硫参与了南非Bthemhveld杂岩的Cu-Ni-PGE（PGE-铂族元素）成矿，这一点已得到广泛认可；然而，污染的程度和程度仍存在争议。

附：英文原文

Title: Contribution of the oldest Paleoproterozoic marine sulfate evaporites to Bushveld Complex Lower Zone mineralization

Author: ‘Mabatho Mapiloko, Marina Yudovskaya, Matthew McCreesh, Tatyana Velivetskaya, Paul Nex, Judith Kinnaird, Richard Montjoie, Andrey Bekker

Issue&Volume: 2025-02-04

Abstract: In the past two decades, multiple-sulfur isotope systematics has become increasingly used as a tool to differentiate sulfur sources with implications for exploration targeting. The involvement of crustal sulfur in triggering the Bushveld Complex (South Africa) Cu-Ni-PGE (PGE—platinum group element) mineralization of the Platreef intrusion is widely recognized; however, the extent and source of contamination are still debated. High-Mg magma of the Uitloop Lower Zone intrusion contained insufficient amounts of mantle-derived sulfur to reach the sulfide saturation required for mineralization. Sulfide saturation was reached when magma assimilated sulfur as it ascended through sedimentary strata deposited before and during the Great Oxidation Episode (GOE). Magmatic sulfides on Uitloop are ³⁴S-enriched and either lack, or show small, mass-independent sulfur isotope fractionation, whereas sulfides from the Archean sedimentary footwall rocks exhibit the Archean-style multiple sulfur isotope covariations. We suggest that assimilation of the early Paleoproterozoic upper Duitschland Formation sulfate evaporites, corresponding to an ingrowth of a mass-dependently fractionated seawater sulfate reservoir at the early stage of the GOE, led to sulfide saturation and formation of Cu-Ni-PGE Platreef-style sulfide deposits. The GOE thus not only changed the oxidation state of the atmosphere and oceans, and the style of sediment-hosted mineral deposits, but also generated the sedimentary sulfate reservoir that since then served as a prolific sulfur source for magmatic ore deposits.

DOI: 10.1130/G52550.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G52550.1/651847/Contribution-of-the-oldest-Paleoproterozoic-marineredirectedFrom=fulltext