Université de Toulouse, UPS-OMP, IRAP, F-31400 Toulouse, France.
Nature. 2011 Apr 21;472(7343):338-41. doi: 10.1038/nature09903. Epub 2011 Apr 6.
Reconstruction of the geological history of Mars has been the focus of considerable attention over the past four decades, with important discoveries being made about variations in surface conditions. However, despite a significant increase in the amount of data related to the morphology, mineralogy and chemistry of the martian surface, there is no clear global picture of how magmatism has evolved over time and how these changes relate to the internal workings and thermal evolution of the planet. Here we present geochemical data derived from the Gamma Ray Spectrometer on board NASA's Mars Odyssey spacecraft, focusing on twelve major volcanic provinces of variable age. Our analysis reveals clear trends in composition that are found to be consistent with varying degrees of melting of the martian mantle. There is evidence for thickening of the lithosphere (17-25 km Gyr(-1)) associated with a decrease in mantle potential temperature over time (30-40 K Gyr(-1)). Our inferred thermal history of Mars, unlike that of the Earth, is consistent with simple models of mantle convection.
火星地质历史的重建一直是过去四十年关注的焦点，关于表面条件变化的重要发现不断涌现。然而，尽管与火星表面形态、矿物学和化学有关的数据大量增加，但对于岩浆作用如何随时间演变以及这些变化与行星内部结构和热演化的关系，仍然没有一个明确的全球图景。在这里，我们展示了美国宇航局火星奥德赛号宇宙飞船上的伽马射线光谱仪得出的地球化学数据，重点研究了 12 个不同年龄的主要火山省。我们的分析揭示了组成上的明显趋势，这些趋势与火星地幔不同程度的熔融相一致。有证据表明，随着时间的推移，地幔潜能温度的下降（30-40 K Gyr^-1）与岩石圈（17-25 km Gyr^-1）的增厚有关。与地球不同，我们推断的火星热历史与简单的地幔对流模型一致。
