Variability in the sulfur isotopic composition in sediments can reflect atmospheric, geologic and biological processes. Evidence for ancient fluvio-lacustrine environments at Gale crater on Mars and a lack of efficient crustal recycling mechanisms on the planet suggests a surface environment that was once warm enough to allow the presence of liquid water, at least for discrete periods of time, and implies a greenhouse effect that may have been influenced by sulfur-bearing volcanic gases. Here we report in situ analyses of the sulfur isotopic compositions of SO₂ volatilized from ten sediment samples acquired by NASA’s Curiosity rover along a 13 km traverse of Gale crater. We find large variations in sulfur isotopic composition that exceed those measured for Martian meteorites and show both depletion and enrichment in ³⁴S. Measured values of δ³⁴S range from −47 ± 14‰ to 28 ± 7‰, similar to the range typical of terrestrial environments. Although limited geochronological constraints on the stratigraphy traversed by Curiosity are available, we propose that the observed sulfur isotopic signatures at Gale crater can be explained by equilibrium fractionation between sulfate and sulfide in an impact-driven hydrothermal system and atmospheric processing of sulfur-bearing gases during transient warm periods.

沉积物中硫同位素组成的变化可反映大气，地质和生物过程。火星大风火山口的古代河湖环境的证据以及行星上缺乏有效的地壳再循环机制的证据表明，表面环境曾经足够温暖，至少在不连续的时间段内允许存在液态水，这意味着可能受到含硫火山气体影响的温室效应。在这里，我们报告了SO ₂的硫同位素组成的原位分析从美国宇航局好奇号流动站沿大风火山口13公里横断面采集的十个沉积物样本中挥发掉。我们发现在硫同位素组成超出那些火星陨石测量并同时显示枯竭和富集在大的变化^34个S.测量δ的值³⁴ S系列从-47±14‰至28±7‰，类似于典型的范围地球环境。尽管对好奇心穿越的地层有有限的地质年代学限制，但我们认为，在大风火山口观察到的硫同位素特征可以通过冲击驱动的热液系统中硫酸盐和硫化物之间的平衡分馏以及在含硫气体的大气处理过程中进行解释。短暂的温暖时期。