Martian Gullies and their Earth Analogues
CONTAINS OPEN ACCESS
Gullies on Mars resemble terrestrial gullies involved in the transport of abundant material down steep slopes by liquid water. However, liquid water should not be stable at the Martian surface. The articles in this volume present the two main opposing theories for Martian gully formation: climate-driven melting of surficial water-ice deposits and seasonal dry-ice sublimation. The evidence presented ranges from remote-sensing observations, to experimental simulations, to comparison with Earth analogues. The opposing hypotheses imply either that Mars has been unusually wet in the last few million years or that it has remained a cold dry desert – both with profound implications for understanding the water budget of Mars and its habitability. The debate questions the limits of remote-sensing data and how we interpret active processes on extra-terrestrial planetary surfaces, even beyond those on Mars, as summarized by the review paper at the beginning of the book.
Time will tell: temporal evolution of Martian gullies and palaeoclimatic implications
Published:January 01, 2019
T. de Haas, S. J. Conway, F. E. G. Butcher, J. Levy, P. M. Grindrod, T. A. Goudge, M. R. Balme, 2019. "Time will tell: temporal evolution of Martian gullies and palaeoclimatic implications", Martian Gullies and their Earth Analogues, S. J. Conway, J. L. Carrivick, P. A. Carling, T. de Haas, T.N. Harrison
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To understand Martian palaeoclimatic conditions and the role of volatiles therein, the spatiotemporal evolution of gullies must be deciphered. While the spatial distribution of gullies has been extensively studied, their temporal evolution is poorly understood. We show that gully size is similar in very young and old craters. Gullies on the walls of very young impact craters (less than a few myr) typically cut into bedrock and are free of latitude-dependent mantle (LDM) and glacial deposits, while such deposits become increasingly evident in older craters. These observations suggest that gullies go through obliquity-driven degradation–accumulation cycles over time, controlled by:...