The sulfur isotope budget of Martian regolith breccia (NWA 7533) has been addressed from conventional fluorination bulk rock analyses and ion microprobe in situ analyses. The bulk rock analyses yield 865 ± 50 ppm S in agreement with LA‐ICP‐MS analyses. These new data support previous estimates of 80% S loss resulting from terrestrial weathering of NWA 7533 pyrite. Pyrite is by far the major S host. Apatite and Fe oxyhydroxides are negligible S carriers, as are the few tiny igneous pyrrhotite–pentlandite sulfide grains included in lithic clasts so far identified. A small nonzero Δ³³S (−0.029 ± 0.010‰) signal is clearly resolved at the 2σ level in the bulk rock analyses, coupled with negative CDT‐normalized δ³⁴S (−2.54 ± 0.10‰), and near‐zero Δ³⁶S (0.002 ± 0.09‰). In situ analyses also yield negative Δ³³S values (−0.05 to −0.30‰) with only a few positive Δ³³S up to +0.38‰. The slight discrepancy compared to the bulk rock results is attributed to a possible sampling bias. The occurrence of mass‐independent fractionation (MIF) supports a model of NWA 7533 pyrite formation from surface sulfur that experienced photochemical reaction(s). The driving force that recycled crustal S in NWA 7533 lithologies—magmatic intrusions or impact‐induced heat—is presently unclear. However, in situ analyses also gave negative δ³⁴S values (+1 to −5.8‰). Such negative values in the hydrothermal setting of NWA 7533 are reflective of hydrothermal sulfides precipitated from H₂S/HS^‐ aqueous fluid produced via open‐system thermochemical reduction of sulfates at high temperatures (>300 °C).

中文翻译：

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火星角砾岩角砾岩NWA 7533的硫预算和硫同位素组成

火星长角砾岩角砾岩（NWA 7533）的硫同位素收支已经通过常规的氟化块岩分析和离子微探针原位分析得到解决。经与LA‐ICP‐MS分析相符，块岩分析的产量为865±50 ppmS。这些新数据支持先前估计的NWA 7533黄铁矿的地面风化引起的80％S损失。硫铁矿是目前主要的S宿主。磷灰石和羟基氧化铁是可忽略不计的S载体，迄今已确定的碎屑岩屑中包含的少数微小火成的黄铁矿-斑脱石硫化物晶粒也是如此。一个小的非零的Δ ³³ S（-0.029±0.010‰）信号被清楚地分辨在散装岩石分析的2σ水平，加上负CDT-归δ ³⁴ S（-2.54±0.10‰），和接近零的Δ ³⁶S（0.002±0.09‰）。原位分析也产生负Δ ³³的价值观（-0.05 -0.30至‰），只有少数Δ阳性³³ s到+ 0.38‰。与散装岩石的结果相比，略有差异是由于可能的采样偏差所致。质量独立分级分离（MIF）的发生支持了由经历光化学反应的表面硫形成NWA 7533黄铁矿的模型。目前尚不清楚在NWA 7533岩性中回收地壳S的驱动力-岩浆侵入或撞击引起的热量。然而，原位分析也给负δ ³⁴价值观（1至-5.8‰）。NWA 7533在水热环境中的这种负值反映了H ₂ S / HS沉淀的水热硫化物^- 在高温（> 300°C）下通过开放系统热化学还原硫酸盐产生的水性流体。