Greenstone belts contain several clues about the evolutionary history of primitive Earth. Here, we describe the volcano-sedimentary rock association exposed along the eastern margin of the Gavião Block, named the Northern Mundo Novo Greenstone Belt (N-MNGB), and present data collected with different techniques, including U–Pb–Hf–O isotopes of zircon and multiple sulfur isotopes (³²S, ³³S, ³⁴S, and ³⁶S) of pyrite from this supracrustal sequence. A pillowed metabasalt situated in the upper section of the N-MNGB is 3337 ± 25 Ma old and has zircon with ε_Hf(t) = −2.47 to −1.40, Hf model ages between 3.75 Ga and 3.82 Ga, and δ¹⁸O = +3.6‰ to +7.3‰. These isotopic data, together with compiled whole-rock trace element data, suggest that the mafic metavolcanic rocks formed in a subduction-related setting, likely a back-arc basin juxtaposed to a continental arc. In this context, the magma interacted with older Eoarchean crustal components from the Gavião Block. Detrital zircons from the overlying quartzites of the Jacobina Group are sourced from Paleoarchean rocks, in accordance with previous studies, yielding a maximum depositional age of 3353 ± 22 Ma. These detrital zircons have ε_Hf(t) = −5.40 to −0.84, Hf model ages between 3.66 Ga and 4.30 Ga, and δ¹⁸O = +4.8‰ to +6.4‰. The pyrite multiple sulfur isotope investigation of the 3.3 Ga supracrustal rocks from the N-MNGB enabled a further understanding of Paleoarchean sulfur cycling. The samples have diverse isotopic compositions that indicate sulfur sourced from distinct reservoirs. Significantly, they preserve the signal of the anoxic Archean atmosphere, expressed by MIF-S signatures (Δ³³S between −1.3‰ to +1.4‰) and a Δ³⁶S/Δ³³S slope of −0.81 that is indistinguishable from the so-called Archean array. A BIF sample has a magmatic origin of sulfur, as indicated by the limited δ³⁴S range (0 to +2‰), Δ³³S ∼ 0‰, and Δ³⁶S ∼ 0‰. A carbonaceous schist shows positive δ³⁴S (2.1‰–3.5‰) and elevated Δ³³S (1.2‰–1.4‰) values, with corresponding negative Δ³⁶S between −1.2‰ to −0.2‰, which resemble the isotopic composition of Archean black shales and suggest a source from the photolytic reduction of elemental sulfur. The pillowed metabasalt displays heterogeneous δ³⁴S, Δ³³S, and Δ³⁶S signatures that reflect assimilation of both magmatic sulfur and photolytic sulfate during hydrothermal seafloor alteration. Lastly, pyrite in a massive sulfide lens is isotopically similar to barite of several Paleoarchean deposits worldwide, which might indicate mass dependent sulfur processing from a global and well-mixed sulfate reservoir at this time.

绿岩带包含一些关于原始地球演化历史的线索。在这里，我们描述了沿 Gavião 地块东缘出露的火山-沉积岩组合，命名为北 Mundo Novo 绿岩带 (N-MNGB)，并提供了使用不同技术收集的数据，包括 U-Pb-Hf-O 同位素来自该地壳层序的黄铁矿的锆石和多种硫同位素（³² S、³³ S、³⁴ S 和³⁶ S）。位于 N-MNGB 上部的枕状变玄武岩年龄为 3337 ± 25 Ma，锆石 ε _Hf ( t ) = -2.47 至 -1.40，Hf 模型年龄介于 3.75 Ga 和 3.82 Ga 之间，δ ¹⁸O = +3.6‰ 至 +7.3‰。这些同位素数据连同汇编的全岩微量元素数据表明，基性变质火山岩形成于与俯冲相关的环境中，可能是与大陆弧并列的弧后盆地。在这种情况下，岩浆与来自 Gavião 地块的更古老的始太古代地壳成分相互作用。根据先前的研究，Jacobina 群上覆石英岩的碎屑锆石来源于古太古代岩石，其最大沉积年龄为 3353 ± 22 Ma。这些碎屑锆石具有 ε _Hf ( t ) = -5.40 至 -0.84，Hf 模型年龄介于 3.66 Ga 和 4.30 Ga 之间，δ ¹⁸O = +4.8‰ 至 +6.4‰。对来自 N-MNGB 的 3.3 Ga 上地壳岩石的黄铁矿多硫同位素研究使人们能够进一步了解古太古代硫循环。样品具有不同的同位素组成，表明硫来自不同的储层。重要的是，它们保留了缺氧太古代大气的信号，由 MIF-S 特征（Δ ³³ S 在 -1.3‰ 到 +1.4‰ 之间）和-0.81的 Δ ³⁶ S/Δ ³³ S 斜率表示- 称为太古代阵列。BIF 样品具有硫的岩浆成因，如有限的δ ³⁴ S 范围（0 至 +2‰）、Δ ³³ S ∼ 0‰ 和 Δ ³⁶ S ∼ 0‰ 所示。碳质片岩显示阳性δ ³⁴ S (2.1‰–3.5‰) 和升高的 Δ ³³ S (1.2‰–1.4‰) 值，相应的负 Δ ³⁶ S 介于 -1.2‰ 到 -0.2‰ 之间，这类似于太古代黑色页岩的同位素组成并表明来自元素硫的光解还原。枕状变玄武岩显示出不均匀的δ ³⁴ S、Δ ³³ S 和 Δ ³⁶ S 特征，反映了热液海底蚀变过程中岩浆硫和光解硫酸盐的同化作用。最后，块状硫化物透镜体中的黄铁矿在同位素上与世界范围内几个古太古代沉积物的重晶石相似，这可能表明此时来自全球且混合良好的硫酸盐储层的质量依赖硫加工。