论文标题
Protonilus Mensae中有十亿或更多年的可能的冰川/冰川循环，火星
A billion or more years of possible periglacial/glacial cycling in Protonilus Mensae, Mars
论文作者
论文摘要
冰川 - 裂解（或冰纹）期或时期的长期循环和时间继承是地球上第四纪地质学的主题。相对较新的工作已经开始探索火星中期至高纬度地区的历史，尤其是在北半球，以证明在亚马逊时期中期至后期的循环性和继承的证据。在这里，我们通过关注Protonilus mensae [PM]（43-490 N，37-590 E）继续进行这项工作。更具体地说，我们讨论，描述和评估PM内的一个区域，该区域跨越了两个古代单元之间的地质接触：[Hnt]，Noachian-Hesperian Epoch过渡单元；和[EHT]早期的Hesperian时期过渡单元。 EHT单元内的深色调（Hirise Image ESP_028457_2255）显示出类似于层状圆的结构的连续覆盖范围[CSC]。后者在地球上的多年冻土区域中观察到，在地球上，表面和/或近地表水的冻融循环很常见，而冷冻扰动也不例外。深色色调地形的火山口大小的频率分布表明，最小年龄约为100 ma，最高年龄约为1 ga。候选CSC的年龄估计属于此分散体内。从地球学上讲，这将候选CSC置于迄今为止火星上确定的最古老的冰川层状地面。
The long-term cyclicity and temporal succession of glacial-periglacial (or deglacial) periods or epochs are keynotes of Quaternary geology on Earth. Relatively recent work has begun to explore the histories of the mid- to higher-latitudinal terrain of Mars, especially in the northern hemisphere, for evidence of similar cyclicity and succession in the Mid to Late Amazonian Epoch. Here, we carry on with this work by focusing on Protonilus Mensae [PM] (43-490 N, 37-590 E). More specifically, we discuss, describe and evaluate an area within PM that straddles a geological contact between two ancient units: [HNt], a Noachian-Hesperian Epoch transition unit; and [eHT] an early Hesperian Epoch transition unit. Dark-toned terrain within the eHt unit (HiRISE image ESP_028457_2255) shows continuous coverage by structures akin to clastically-sorted circles [CSCs]. The latter are observed in permafrost regions on Earth where the freeze-thaw cycling of surface and/or near-surface water is commonplace and cryoturbation is not exceptional. The crater-size frequency distribution of the dark-toned terrain suggests a minimum age of ~100 Ma and a maximum age of ~1 Ga. The age estimates of the candidate CSCs fall within this dispersion. Geochronologically, this places the candidate CSCs amongst the oldest periglacial landforms identified on Mars so far.
