Astromaterials Research and Exploration Science, NASA Johnson Space Center, Houston, TX 77058, USA.
Science. 2010 Sep 10;329(5997):1334-7. doi: 10.1126/science.1192863.
Carbon dioxide is a primary component of the martian atmosphere and reacts readily with water and silicate rocks. Thus, the stable isotopic composition of CO2 can reveal much about the history of volatiles on the planet. The Mars Phoenix spacecraft measurements of carbon isotopes [referenced to the Vienna Pee Dee belemnite (VPDB)] [delta13C(VPDB) = -2.5 +/- 4.3 per mil (per thousand)] and oxygen isotopes [referenced to the Vienna standard mean ocean water (VSMOW)] (delta18O(VSMOW) = 31.0 +/- 5.7 per thousand), reported here, indicate that CO2 is heavily influenced by modern volcanic degassing and equilibration with liquid water. When combined with data from the martian meteorites, a general model can be constructed that constrains the history of water, volcanism, atmospheric evolution, and weathering on Mars. This suggests that low-temperature water-rock interaction has been dominant throughout martian history, carbonate formation is active and ongoing, and recent volcanic degassing has played a substantial role in the composition of the modern atmosphere.
二氧化碳是火星大气的主要成分，它很容易与水和硅酸盐岩石发生反应。因此，CO2 的稳定同位素组成可以揭示火星上挥发物的历史。这里报告的火星凤凰号航天器对碳同位素（相对于维也纳 Pee Dee 贝壳（VPDB））[delta13C(VPDB) = -2.5 +/- 4.3 千分比（每千）]和氧同位素（相对于维也纳标准平均海水（VSMOW））（delta18O(VSMOW) = 31.0 +/- 5.7 千分比）的测量结果表明，CO2 受到现代火山释放和与液态水平衡的强烈影响。当与火星陨石的数据结合起来时，可以构建一个通用模型，该模型限制了火星上水、火山活动、大气演化和风化的历史。这表明，低温水-岩石相互作用在火星历史上一直占主导地位，碳酸盐的形成是活跃且持续的，最近的火山释放对现代大气的组成起了重要作用。
