Neish C D, Barnes J W, Sotin C, MacKenzie S, Soderblom J M, Le Mouélic S, Kirk R L, Stiles B W, Malaska M J, Le Gall A, Brown R H, Baines K H, Buratti B, Clark R N, Nicholson P D
Department of Physics and Space Sciences Florida Institute of Technology Melbourne Florida USA.
Department of Physics University of Idaho Moscow Idaho USA.
Geophys Res Lett. 2015 May 28;42(10):3746-3754. doi: 10.1002/2015GL063824. Epub 2015 May 26.
We examined the spectral properties of a selection of Titan's impact craters that represent a range of degradation states. The most degraded craters have rims and ejecta blankets with spectral characteristics that suggest that they are more enriched in water ice than the rims and ejecta blankets of the freshest craters on Titan. The progression is consistent with the chemical weathering of Titan's surface. We propose an evolutionary sequence such that Titan's craters expose an intimate mixture of water ice and organic materials, and chemical weathering by methane rainfall removes the soluble organic materials, leaving the insoluble organics and water ice behind. These observations support the idea that fluvial processes are active in Titan's equatorial regions.
我们研究了泰坦上一系列代表不同退化状态的撞击坑的光谱特性。退化程度最高的撞击坑的边缘和喷出物覆盖层具有光谱特征，这表明它们比泰坦上最新形成的撞击坑的边缘和喷出物覆盖层富含更多的水冰。这种变化过程与泰坦表面的化学风化作用相一致。我们提出了一个演化序列，即泰坦上的撞击坑暴露了水冰和有机物质的紧密混合物，甲烷降雨引起的化学风化作用去除了可溶性有机物质，留下了不溶性有机物和水冰。这些观测结果支持了泰坦赤道地区存在活跃河流作用的观点。
