Ph.D. (Doctor of Philosophy)
Department of Earth, Atmosphere and Environment
Although Mars is cold and dry today, many lines of evidence suggest that ancient Mars had large amount of water and surface fluvial processes. However, climate modelers have encountered difficulties in modeling such early warm and wet conditions with an above freezing temperature, mainly due to the Martian orbit being further away from the Sun and the faintness of the young Sun. The main purpose of this dissertation is to test the ancient Martian climate hypotheses by investigating the spatial pattern of valley network (VN) properties that can survive post-formational modification (i.e., the robust characteristics) and by analogizing the Earth streams and Martian VNs. In the dissertation, I developed a spatial analysis method to assess the associations between properties of streams/VNs and their corresponding environmental factors. I then utilized this tool to analyze and analogize one VNs' robust characteristic (junction angle) and its corresponding environmental factors and estimated the early Mars climatic conditions. I also calculated Martian watersheds' maturity by comparing their energy dissipation with those of Optimal Channel Network (OCN) to investigate whether the "warm" duration on Mars is long enough. Our results suggest that the ancient Mars was at least "episodically warm” and had surface runoff long enough to carve the Martian surface in some regions and the climatic conditions of the early Mars was similar to those of the arid/sub-arid regions on Earth.
Cang, Xuezhi, "A "Warm" or "Cold" Early Mars: Evidence From Valley Networks" (2021). Graduate Research Theses & Dissertations. 6893.
Northern Illinois University
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