火星地下笼形水合物甲烷捕获的变化
Variability of the methane trapping in martian subsurface clathrate hydrates
摘要：
最近的观测表明，火星大气中有甲烷CH 4的痕迹。然而，由于根据光化学，甲烷在火星大气中的寿命估计约为300-600年，因此最近的文献中提到了甲烷从地下储层或活跃的甲烷主要来源释放的情况。在现有的设想中，有人提出，位于火星近地表下的笼形水合物可能是检测到的少量甲烷的来源。在这里，我们准确地确定这些笼形水合物的组成，作为温度和气相组成的函数，通过使用基于实验数据的混合统计热力学模型。与其他最近的工作相比，我们的模型使我们能够计算笼形水合物的组成，通过考虑其主要化合物，即二氧化碳，氮气和氩气，以及甲烷，形成了一个更合理的火星大气组成。此外，由于在我们的模型中没有低温限制，我们能够确定在极帽中测量的极端温度下形成的笼形水合物的组成。我们的研究结果表明，富含甲烷的笼形水合物可能是稳定的，在火星的地下，只有当一个原始的CH 4丰富的大气层已经存在，或者如果一个地下来源的CH 4已经（或仍然）存在。
英文摘要：
Recent observations have evidenced traces of methane CH4 heterogeneously distributed in the martian atmosphere. However, because the lifetime of CH4 in the atmosphere of Mars is estimated to be around 300-600 years on the basis of photochemistry, its release from a subsurface reservoir or an active primary source of methane have been invoked in the recent literature. Among the existing scenarios, it has been proposed that clathrate hydrates located in the near subsurface of Mars could be at the origin of the small quantities of the detected CH4. Here, we accurately determine the composition of these clathrate hydrates, as a function of temperature and gas phase composition, by using a hybrid statistical thermodynamic model based on experimental data. Compared to other recent works, our model allows us to calculate the composition of clathrate hydrates formed from a more plausible composition of the martian atmosphere by considering its main compounds, i.e. carbon dioxyde, nitrogen and argon, together with methane. Besides, because there is no low temperature restriction in our model, we are able to determine the composition of clathrate hydrates formed at temperatures corresponding to the extreme ones measured in the polar caps. Our results show that methane enriched clathrate hydrates could be stable in the subsurface of Mars only if a primitive CH4-rich atmosphere has existed or if a subsurface source of CH4 has been (or is still) present.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
