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

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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?