论文标题
火星上年轻沉积岩的年龄和侵蚀率
The Age and Erosion Rate of Young Sedimentary Rock on Mars
论文作者
论文摘要
Medusae Fossae地层（MFF）是火星赤道附近的神秘沉积单元，其形成过程不确定和绝对年龄。由于风向绘制的表面严重，很难使用基于现有火山口数数据的火山口大小频率分布函数来确定MFF的绝对模型年龄。我们创建了一个新的两参数模型，该模型通过将缝隙视为随机泊松过程来估计年龄和恒定的侵蚀率（$β$）。我们的研究使用了从上下文摄像机图像收集的新火山口数数据，用于MFF和其他年轻的赤道沉积岩。基于我们的新模型，中央MFF在$> $ 1.5 GYR中形成较低的侵蚀率（$ <$ <$ <$ 650 nm yr $^{ - 1} $），而East MFF，Far East MFF和Zephyria Planum最有可能形成$ <$ <$ <$ <$ <$ <$ <$ <$ <$> $ 740 nm $^$^$^$^$^{ - 1.1美元。大风火山口和东方坦率的莫利斯蒙斯（Aeolis Mons）的顶部（非正式地称为夏普山）的年龄相对较小，侵蚀率较低。基于估计的侵蚀率（由于快速侵蚀允许亚稳态冰冰），我们还确定了包括Zephyria planum在内的几个地点，是可见的地下赤道赤道水冰的合理位置，可通过伽玛 - 射线光谱谱图或中子光谱检测到可检测到的位置。除了确认火星上的$ <$ <$ <$ <$ 1.5 $ <$ <$ <$ <$ <$ <$ <$ <$ <$ <$的岩层，并区分年龄较小和年轻的MFF站点外，我们发现快速擦除的位置具有较年轻的年龄，而MFF的侵蚀较慢的位置具有较老的年龄较大的年龄。
The Medusae Fossae Formation (MFF) is an enigmatic sedimentary unit near the equator of Mars, with an uncertain formation process and absolute age. Due to the heavily wind-eroded surface, it is difficult to determine the absolute model age of the MFF using a one-parameter model based on the crater size-frequency distribution function with existing crater count data. We create a new two-parameter model that estimates both age and a constant erosion rate ($β$) by treating cratering as a random Poisson process. Our study uses new crater count data collected from Context Camera imagery for both the MFF and other young equatorial sedimentary rock. Based on our new model, the Central MFF formed $>$1.5 Gyr ago and had low erosion rates ($<$650 nm yr$^{-1}$), whereas the East MFF, Far East MFF, and Zephyria Planum most likely formed $<$1.5 Gyr ago and had higher erosion rates ($>$740 nm $^{-1}$). The top of Aeolis Mons (informally known as Mount Sharp) in Gale Crater and Eastern Candor have relatively young ages and low erosion rates. Based on the estimated erosion rates (since fast erosion permits metastable shallow ice), we also identify several sites, including Zephyria Planum, as plausible locations for shallow subsurface equatorial water ice that is detectable by gamma-ray spectroscopy or neutron spectroscopy. In addition to confirming $<$1.5 Gyr sedimentary rock formations on Mars, and distinguishing older and younger MFF sites, we find that fast-eroding locations have younger ages and MFF locations with slower erosion have older best-fit ages.
