In the Late Noachian to Early Hesperian period, rivers transported detritus from igneous source terrains to a downstream lake within Gale crater, creating a stratified stack of fluviolacustrine rocks that is currently exposed along the slopes of Mount Sharp. Controversy exists regarding the paleoclimate that supported overland flow of liquid water at Gale crater, in large part because little is known about how chemical and mineralogical paleoclimate indicators from mafic‐rock dominated source‐to‐sink systems are translated into the rock record. Here, we compile data from basaltic terrains with varying climates on Earth in order to provide a reference frame for the conditions that may have prevailed during the formation of the sedimentary strata in Gale crater, particularly focusing on the Sheepbed and Pahrump Hills members. We calculate the chemical index of alteration for weathering profiles and fluvial sediments to better constrain the relationship between climate and chemical weathering in mafic terrains, a method that best estimates the cooler limit of climate conditions averaged over time. We also compare X‐ray diffraction patterns and mineral abundances from fluvial sediments in varying terrestrial climates and martian mudstones to better understand the influence of climate on secondary mineral assemblages in basaltic terrains. We show that the geochemistry and mineralogy of most of the fine‐grained sedimentary rocks in Gale crater display first‐order similarities with sediments generated in climates that resemble those of present‐day Iceland, while other parts of the stratigraphy indicate even colder baseline climate conditions. None of the lithologies examined at Gale crater resemble fluvial sediments or weathering profiles from warm (temperate to tropical) terrestrial climates.

中文翻译：

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火星盖尔陨石坑古环境的从源到汇的陆地模拟


在诺亚纪晚期到西方早期，河流将碎屑从火成岩源区输送到盖尔陨石坑内的下游湖泊，形成了目前沿夏普山山坡暴露的分层河湖相岩石堆。关于支持盖尔陨石坑液态水陆上流动的古气候存在争议，很大程度上是因为人们对基性岩主导的源-汇系统的化学和矿物学古气候指标如何转化为岩石记录知之甚少。在这里，我们汇编了地球上不同气候的玄武岩地形的数据，以便为盖尔陨石坑沉积地层形成过程中可能存在的条件提供参考框架，特别是关注羊床和帕朗山成员。我们计算风化剖面和河流沉积物的化学变化指数，以更好地限制镁铁质地形中气候与化学风化之间的关系，这是一种最好地估计随时间平均气候条件的较冷极限的方法。我们还比较了不同陆地气候下的河流沉积物和火星泥岩的 X 射线衍射图谱和矿物丰度，以更好地了解气候对玄武岩地形次生矿物组合的影响。我们表明，盖尔陨石坑中大多数细粒沉积岩的地球化学和矿物学与在类似于当今冰岛的气候中生成的沉积物表现出一级相似性，而地层的其他部分表明基线气候条件甚至更冷。 在盖尔陨石坑检查的岩性中没有一个类似于温暖（温带到热带）陆地气候的河流沉积物或风化剖面。