A primary motivation for the exploration of planetary bodies is to determine if, where, and when life may have existed beyond Earth, and the nature of the habitats that supported it. Given the critical role of water in the sustenance of life, the presence of liquid water has served as a practical minimum criterion to establish the existence of a habitable environment. As a result, a major focus of the exploration of Mars has been to characterize the nature and evolution of the planet’s hydrologic system. However, despite decades of intense study, many fundamental questions regarding the nature of the hydrologic system of early Mars remain unresolved. Of particular importance is whether the hydrologic system was characterized by warm and wet or cold and icy conditions. The objective of this dissertation is to determine if the cold and icy conditions predicted by climate models are consistent with the wide array of hydrologic features preserved across Mars which have often been cited as evidence for warm and wet conditions. In order to address this problem, a number of geophysical and geomorphologic analyses are performed utilizing a broad range of remote sensing data sets. Results of the dissertation demonstrate that a variety of martian hydrologic features could plausibly have been produced by surficial interactions of glacial and volcanic products predicted to have been widely emplaced across Mars during its early history. The formation of hydrologic features in this manner is possible under cold and icy conditions and therefore does not require ambient warm and wet conditions or anomalous heating mechanisms inferred by previous studies. Additional results provide the potential through suggested future work to directly recognize signatures of cold and icy formative conditions in the morphology of martian hydrologic features. Ultimately, this dissertation helps to reconcile, in part, the prevalence of preserved hydrologic features across Mars with the cold and icy early climate predicted by modeling efforts. Therefore the dissertation represents an incremental contribution to constraining the precise nature of the early Mars hydrologic system that will help to guide future exploration efforts for habitable environments and signs of life.
Cassanelli, James,
"Evaluating the Hydrology of a Cold and Icy Early Mars"
(2019).
Earth, Environmental and Planetary Sciences Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.26300/qjbg-8250
