火星Protonilus Mensae可能存在十亿年或更长时间的冰缘/冰川循环
A billion or more years of possible periglacial/glacial cycling in Protonilus Mensae, Mars
摘要：
冰期-冰缘期（或冰消期）的长期旋回性和时间序列是地球第四纪地质学的重要内容。相对较新的工作已经开始探索火星中高纬度地形的历史，特别是在北半球，寻找类似的周期性和继承的证据，在中晚亚马逊时代。在这里，我们通过关注Protonilus Mensae [PM]（43-490 N，37-590 E）继续这项工作。更具体地说，我们讨论，描述和评估PM内的一个区域，该区域跨越两个古老单位之间的地质接触：[HNt]，诺亚纪-西方纪过渡单位;和[eHT]早期西方纪过渡单位。eHt单元内的暗色调地形（HiRISE图像ESP_028457_2255）显示了类似于分类分类圆[CSC]的结构的连续覆盖。后者是在地球上的永久冻土区观察到的，在那里，地表水和/或近地表水的冻融循环是司空见惯的，低温扰动也不例外。暗色调地形的陨石坑大小频率分布表明，最小年龄约为100 Ma，最大年龄约为1 Ga。候选CSC的年龄估计值落在该分散范围内。从地质年代学的角度来看，这是迄今为止在火星上发现的最古老的冰缘地貌之一。
英文摘要：
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.
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。
