The surface of Mars has experienced progressive oxidation, resulting in the formation of sulfate minerals as evidenced from surface exploration missions. However, no clear evidence for the presence of sulfate minerals has been reported within Martian meteorites. This study examined sulfur speciation in impact glasses of three basaltic shergottites, Elephant Moraine (EETA) 79001, Larkman Nunatak (LAR) 06319, and Dhofar 019, using X-ray absorption near-edge structure (XANES) spectroscopy. The measured XANES spectra were classified into four types: (1) sulfide, (2) highly reduced sulfide glass (∼IW+1), (3) mixture of sulfide and sulfate, and (4) sulfate. The sulfate spectra observed from EETA79001 and LAR 06319 were mixed with sulfide from the reduced igneous host rock as impact glasses were formed by shock on the surface of Mars, both sulfide and sulfate would have possibly originated on Mars. Besides, highly reduced sulfide present in the same impact glasses is inconsistent with secondary alteration on the oxic Earth’s environment. In contrast to EETA79001 and LAR 06319, all of the XANES spectra from Dhofar 019 showed the only sulfate, whose origin is most likely from terrestrial alteration. Combining with the geochemical signatures of volatile elements (e.g., D/H, C, and halogens) in impact glasses of EETA79001 and LAR 06319, we propose two possible scenarios for the formation of sulfate species to the shergottite host-rocks: (i) oxidation of sulfide minerals by subsurface oxic water in Mars, or (ii) precipitation of sulfate mineral derived from Martian subsurface water. The difference between the two models is the source of S(VI) species, whether it originated from (i) magmatic sulfide in shergottite or (ii) sulfate ion in the subsurface water/ice. Both models indicate that the ancient (∼4 Ga) water reservoir might have already been oxic, and it requires post-magmatic water–rock interaction that formed sulfate minerals whose oxidized signatures were incorporated into impact glass.

火星表面经历了逐渐氧化，导致形成了硫酸盐矿物，这从表面勘探任务中可以看出。然而，没有明确证据表明火星陨石中存在硫酸盐矿物。本研究使用 X 射线吸收近边结构 (XANES) 光谱检查了三种玄武岩 Shergottites、大象冰碛 (EETA) 79001、Larkman Nunatak (LAR) 06319 和 Dhofar 019 的冲击玻璃中的硫形态。测量的 XANES 光谱分为四种类型：(1) 硫化物，(2) 高度还原的硫化物玻璃 (~IW+1)，(3) 硫化物和硫酸盐的混合物，以及 (4) 硫酸盐。从 EETA79001 和 LAR 06319 观测到的硫酸盐光谱与来自还原火成岩主岩的硫化物混合，因为撞击玻璃是由火星表面的冲击形成的，硫化物和硫酸盐都可能起源于火星。此外，同一冲击玻璃中存在的高度还原的硫化物与含氧地球环境的二次改变不一致。与 EETA79001 和 LAR 06319 相比，佐法尔 019 的所有 XANES 光谱都显示出唯一的硫酸盐，其起源最有可能来自陆地变化。结合 EETA79001 和 LAR 06319 冲击玻璃中挥发性元素（例如，D/H、C 和卤素）的地球化学特征，我们提出了两种可能的情况，用于形成辉长岩主岩中的硫酸盐物种：（i）由火星地下含氧水氧化硫化物矿物，或 (ii) 源自火星地下水的硫酸盐矿物沉淀。两种模型的区别在于S(VI)种的来源，它是否起源于（i）shergottite中的岩浆硫化物或（ii）地下水/冰中的硫酸根离子。两个模型都表明，古老的（~4 Ga）水库可能已经是含氧的，它需要岩浆后水-岩石相互作用，形成硫酸盐矿物，其氧化特征被结合到撞击玻璃中。