Internal textures, multiple sulfur isotopic compositions, and contents of gold, selenium, and molybdenum of ore-related pyrites from a Neoarchean carbonate-facies BIF-hosted gold deposit in Quadrilátero Ferrífero were investigated to elucidate the source(s) of sulfur. Sodium hypochlorite etching and BSE imaging revealed pervasive zoning in pyrites. Five different growth zones (Py1a, Py1b, Py2, Py3, and Py4) and six types of zoning (Type A–Type F) were identified. Two pyrite generations were distinguished in ores: G1 (Py1a and Py1b) and G2 (Py2, Py3, Py4). Both G1 and G2 have positive Δ³³S, but the magnitudes of G1 are higher. The G1-relevant fluids can be shallow-sourced, whereas the G2-related auriferous fluids are most likely deep-sourced metamorphic fluids derived from devolatilization of the lower succession of the Nova Lima Group (metavolcanics and metasedimentary rocks) during metamorphism, with fluid–rock interactions during fluid ascent and at the depositional site. The negative δ³⁴S, higher selenium contents, and carbonates inclusions of Py1a contrast with the positive δ³⁴S, lower selenium contents, and carbonaceous material inclusions of Py2, Py3, and Py4. The Lamego system possibly started with shallow-sourced oxidized and low-gold fluids (Py1a), closely followed by mixing in of deep-seated reduced auriferous fluids (Py2, Py3, Py4) initiated by tectonic activities. The oscillatory zoning of Py2 with the highest gold contents consists of alternating gold-rich and gold-poor laminae, indicating that fault-valve activity is a trigger of gold deposition. The sulfidation of siderite in BIF (desulfidation of auriferous fluids) related to the formation of ore-related pyrites also contributed to gold precipitation.

研究了QuadriláteroFerrífero的新古代碳酸盐相BIF所含金矿床的内部质地，多种硫同位素组成以及与矿石有关的黄铁矿中金，硒和钼的含量，以阐明硫的来源。次氯酸钠蚀刻和BSE成像显示黄铁矿中普遍存在分区。确定了五个不同的生长区（Py1a，Py1b，Py2，Py3和Py4）和六种类型的分区（A型至F型）。矿石中有两个黄铁矿世代：G1（Py1a和Py1b）和G2（Py2，Py3，Py4）。无论G1和G2具有积极的Δ ³³S，但G1的大小更高。与G1相关的流体可以是浅来源的，而与G2相关的金铁流体很可能是在变质过程中Nova Lima组较低阶次（挥发火山岩和变质沉积岩）的脱挥发分而衍生的深源变质流体。流体上升过程中和沉积点的岩石相互作用。负δ ³⁴的Py1a对比度S，更高硒含量，和碳酸盐的夹杂物与正δ ³⁴S，较低的硒含量以及Py2，Py3和Py4的含碳物质夹杂物。Lamego系统可能从浅来源的氧化和低金的流体（Py1a）开始，紧接着是由构造活动引发的深层还原的含金铁流体（Py2，Py3，Py4）的混合。具有最高金含量的Py2的振荡区带由富金和贫金薄片交替组成，表明断层阀活动是金沉积的触发因素。与矿石相关黄铁矿的形成有关的BIF中的菱铁矿的硫化（金铁流体的脱硫）也有助于金的沉淀。