The exploration of the solar system has shown that mass movement is a common process on the surface of the terrestrial planets (Mercury, Venus, Mars) and on many moons, including our own. However, it is on Mars that mass movements represent a major geomorphologic force both in terms of frequency, volume (often greater than 10km3, with a record volume of 106 km3), and runout, normally longer than several tens of kilometers. The study of landslides and more in general of mass movements on Mars has important implications for assessing the rock and solid properties and is a tool for understanding the geologic and climatic history of the planet. In contrast to our planet, where a landslide deposit is erased or covered after few thousands of years, mass movements on Mars are still perfectly preserved after times that may be greater than 1 billion years, making of such impulsive events a key for understanding the conditions of the planetary surfaces deep in time. In particular, landslides and their associated primary and secondary deposits may shed light on the possible presence of water or ice on the planet at the instant of flow, which is of great astrobiological importance. Firstly, we describe the different types of landslides on Mars. Many types are similar to those on Earth, albeit often at a larger scales. We document the characteristics of slumps and rock avalanches, most of which occur in Valles Marineris, a 4000km-long system of 6-8km deep gorges. Landslides in Valles Marineris exhibit a variety of morphologies on their surfaces, such as Toreva blocks, longitudinal grooves, pressure ridges, run-ups on pre-existing mounds indicating high speed of emplacement. Other forms of mass movements are dubious of at least not as common as they are on Earth. Rockfalls have been documented in some cases, but their smaller size can be spotted only with high-resolution cameras. The presence of slow-expanding lateral spreads may indicate deep clay layers. Some landforms may be interpreted as debris flows and may thus be related to water. Narrow and thin slope lineae may be replenished from under a rock cap, an occurrence that, if genuine, has astrobiological implications. Mixed ejecta-landslides are a peculiar class of movements unknown on Earth. Outside Valles Marineris, mass movements occur especially but not exclusively at the craters rims or inside outflows channels. The largest landslides on Mars and of the whole solar system, the aureoles, can be identified at the borders of the Olympus Mons volcano, with runouts up to 700 kilometers. The analysis of many events demonstrates that similar to Earth, the ratio between the fall height and the runout, which is a proxy for the friction coefficient, diminishes with the mass movement volume. This may be related to environmental constraints.
Crosta, G., De Blasio, F., Frattini, P., Valbuzzi, E. (2021). Mass-Movements on the Mars. In A. Günther (a cura di), Treatise on Geomorphology Vol 5 (pp. 477-499). Elsevier [10.1016/B978-0-12-818234-5.00063-8].
Mass-Movements on the Mars
Crosta G. B.;De Blasio F. V.;Frattini P.;
2021
Abstract
The exploration of the solar system has shown that mass movement is a common process on the surface of the terrestrial planets (Mercury, Venus, Mars) and on many moons, including our own. However, it is on Mars that mass movements represent a major geomorphologic force both in terms of frequency, volume (often greater than 10km3, with a record volume of 106 km3), and runout, normally longer than several tens of kilometers. The study of landslides and more in general of mass movements on Mars has important implications for assessing the rock and solid properties and is a tool for understanding the geologic and climatic history of the planet. In contrast to our planet, where a landslide deposit is erased or covered after few thousands of years, mass movements on Mars are still perfectly preserved after times that may be greater than 1 billion years, making of such impulsive events a key for understanding the conditions of the planetary surfaces deep in time. In particular, landslides and their associated primary and secondary deposits may shed light on the possible presence of water or ice on the planet at the instant of flow, which is of great astrobiological importance. Firstly, we describe the different types of landslides on Mars. Many types are similar to those on Earth, albeit often at a larger scales. We document the characteristics of slumps and rock avalanches, most of which occur in Valles Marineris, a 4000km-long system of 6-8km deep gorges. Landslides in Valles Marineris exhibit a variety of morphologies on their surfaces, such as Toreva blocks, longitudinal grooves, pressure ridges, run-ups on pre-existing mounds indicating high speed of emplacement. Other forms of mass movements are dubious of at least not as common as they are on Earth. Rockfalls have been documented in some cases, but their smaller size can be spotted only with high-resolution cameras. The presence of slow-expanding lateral spreads may indicate deep clay layers. Some landforms may be interpreted as debris flows and may thus be related to water. Narrow and thin slope lineae may be replenished from under a rock cap, an occurrence that, if genuine, has astrobiological implications. Mixed ejecta-landslides are a peculiar class of movements unknown on Earth. Outside Valles Marineris, mass movements occur especially but not exclusively at the craters rims or inside outflows channels. The largest landslides on Mars and of the whole solar system, the aureoles, can be identified at the borders of the Olympus Mons volcano, with runouts up to 700 kilometers. The analysis of many events demonstrates that similar to Earth, the ratio between the fall height and the runout, which is a proxy for the friction coefficient, diminishes with the mass movement volume. This may be related to environmental constraints.
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