Formation of recent martian gullies through melting of extensive water-rich snow deposits

  title={Formation of recent martian gullies through melting of extensive water-rich snow deposits},
  author={Philip R. Christensen},
The observation of gullies on Mars indicates the presence of liquid water near the surface in recent times, which is difficult to reconcile with the current cold climate. Gullies have been proposed to form through surface runoff from subsurface aquifers or through melting of near-surface ice under warmer conditions. But these gullies are observed to occur preferentially in cold mid-latitudes, where the presence of liquid water is less likely, and on isolated surfaces where groundwater seepage… 
Formation of Martian Gullies by the Action of Liquid Water Flowing Under Current Martian Environmental Conditions
[1] Geomorphic evidence suggests that recent gullies on Mars were formed by fluvial activity. The Martian gully features are significant because their existence implies the presence of liquid water
Formation of gullies on Mars: Link to recent climate history and insolation microenvironments implicate surface water flow origin
Analysis of the insolation geometry of this pole-facing crater wall, and similar occurrences in other craters at these latitudes on Mars, shows that they are uniquely favored for accumulation of snow and ice, and a relatively more rapid exposure to warmer summer temperatures.
Identification of Mars gully activity types associated with ice composition
The detection of geologically recent channels at the end of the twentieth century rapidly suggested that liquid water could have been present on Mars up to recent times. A mechanism involving melting
Martian gullies: a comprehensive review of observations, mechanisms and insights from Earth analogues
Abstract Upon their discovery in 2000, Martian gullies were hailed as the first proof of recent (i.e. less than a few million years) flowing liquid water on the surface of a dry desert planet. Many
Gullies, polygons and mantles in Martian permafrost environments: cold desert landforms and sedimentary processes during recent Martian geological history
Abstract A range of cold desert landforms are found on the Martian surface that have been interpreted to indicate prevailing frozen and hyper-arid conditions for at least the past several million


Formation of Recent Martian Debris Flows by Melting of Near-Surface Ground Ice at High Obliquity
It is shown that these gullies on Mars may result from the melting of water ice in the top few meters of the martian subsurface at high obliquity, and that above-freezing temperatures can occur in the near surface of Mars, but are only predicted at latitudes and for slope orientations corresponding to where the gullies have been observed on Mars.
Recent gullies on Mars and the source of liquid water
Geologic features resembling terrestrial water-carved gullies imply that liquid water has flowed recently on the surface of Mars and challenge our views of the present-day low-temperature
Possible precipitation of ice at low latitudes of Mars during periods of high obliquity
Most of the old cratered highlands of Mars are dissected by branching river valleys that appear to have been cut by running water1,2 yet liquid water is unstable everywhere on the martian surface. In
Evidence for recent climate change on Mars from the identification of youthful near-surface ground ice
Observational evidence for a mid-latitude reservoir of near-surface water ice occupying the pore space of soils is reported and it is inferred that the reservoir was created during the last phase of high orbital obliquity less than 100,000 years ago, and is now being diminished.
Metastability of liquid water on Mars
  • M. Hecht
  • Physics, Environmental Science
  • 2001
Abstract A simple model of local heat transport on Mars demonstrates that transient melting of ice may occur in depressions and gullies nearly anywhere on the planet where thin ice is illuminated by
Liquid CO2 breakout and the formation of recent small gullies on Mars
We show that the action of a CO2 suspended flow could have produced the recent small gullies on Mars, and, hence, that liquid water is not required. The model involves the build‐up of a liquid‐CO2
Evidence for recent groundwater seepage and surface runoff on Mars.
Gullies within the walls of a very small number of impact craters, south polar pits, and two of the larger martian valleys display geomorphic features that can be explained by processes associated with groundwater seepage and surface runoff.
The distribution and behavior of Martian ground ice during past and present epochs
Mars undergoes significant oscillations in its orbit, which will have a pronounced effect on its climate and, in particular, on the behavior of subsurface water ice. We explore and map the behavior
On the possibility of liquid water on present‐day Mars
Using a validated general circulation model, we determine where and for how long the surface pressure and surface temperature on Mars meet the minimum requirements for the existence of liquid water