Thumbprint terrain in the northern lowlands of Mars: Assessment of its modes of formation and relations to the Mars ocean

我们研究的主要目标是使用中等分辨率的图像，例如THEMIS-IR（白天和夜间，分辨率为100米/像素），系统地搜索、定位和绘制整个火星北半球所有出现的指纹地形（TPT）。迄今为止，唯一的TPT地图是Lockwood等人[1992]在维京图像（名义分辨率为~225 m/x）的基础上编制的地图。现代图像（例如，THEMIS-IR日间图像）与旧的维京号数据相比，质量和覆盖范围都更好。这种系统的TPT制图结果为测试北部低地这类地形的地层模型和水/泥储层的演化提供了必要的基础。这项研究的第一阶结果将是TPT产状的地质背景和地层特征。这种概括性制图也将允许识别关键区域，在这些区域中，可以使用高分辨率图像测试TPT地层和结构的细节。我们的研究旨在解决以下科学问题，这些问题对于理解TPT的性质至关重要，并且与火星海洋假说和以前的水/泥体的各个方面密切相关。TPT的特征形态是否代表了不同的形成模式？可以制定哪些标准来区分TPT地层的冰川（如冰芯冰碛）和泥火山作用模式？是否有证据表明TPT有不同的来源？是什么告诉我们关于每个特定地区TPT起源的发展标准？在火星的哪些地区，TPT的形成与冰川或泥火山作用有关，或者两者都有？

The primary goal of our study is a systematic search, location, and mapping of all occurrences of the thumbprint terrain (TPT) within the entire northern hemisphere of Mars using medium-resolution images, e.g., THEMIS-IR (both day- and nighttime, resolution is 100 m/px). So far, the only map of the TPT is the one by Lockwood et al. [1992] compiled on the base of the Viking images (nominal resolution is ~225 m/x). The modern images (e.g., THEMIS-IR daytime) have a superior quality and coverage compared with the older Viking data. Results of this systematic TPT mapping represent a necessary basis to test formation models of this type of terrain and evolution of the water/mud reservoir within the northern lowlands. The first-order results of this study will be the characterization of the geological settings and stratigraphy of the occurrences of the TPT. This synoptic mapping will also allow identification of the key areas in which details of TPT stratigraphy and structure can be tested with use of the high-resolution images. Our study is aimed to address the following scientific questions that have key importance for the understanding of the nature of the TPT and that are closely related to various aspects of the Martian ocean hypothesis and former water/mud bodies. Are the characteristic morphologies of the TPT representing different modes of formation? What sets criteria can be developed to distinguish the glacial (e.g., ice-cored moraines) and mud volcanism mode of the TPT formation? Is there evidence for the TPT of different origin? What tell us the developed criteria about the origin of the TPT in each specific region? In which regions of Mars is TPT formation related to either glacial, or mud volcanic processes, or both?