The Department of Earth & Environmental Sciences is pleased to present, "Comparing Climate Models of Noachian Mars to determine how Large-Scale Fluvial" Features Formed' by Ryan Woods.
In 1971, Mariner 9 gave evidence of past water activity on Mars. Since then, the search for liquid water and for potential life had been on the forefront of planetary science. Over the next few decades there were many advances in technology, allowing for more detailed information from the orbiters and landers sent to Mars. Our understanding of where life could be supported also grew with the discovery of extremophiles on Earth, found in locations previously thought to contain no signatures of life.
Each mission to Mars has revealed more information about its surface features, and these features relay information about its past. Large-scale valley networks, alluvial fans and interdunal lake formations are among the many geomorphological features found on Mar’s surface. These are all found on crust from the Noachian Era however, which was between 4.1 and 3.7 Ga. All of these features require liquid water to be flowing on the surface of Mars, and the source of this water has lead to some debate.
There are three proposed models for how these features could have formed. They are labelled as the ‘Wet and Warm Model’, the ‘Episodic Model’ and the ‘Cold and Icy Model’. The Warm and Wet Model describes early Mars similar to Earth, with rainfall and streams creating these features. The Episodic Model agrees that rainfall created the geomorphogical features; however it states that the rainfall was created by impacts and volcanism, and occurred episodically rather than continuously. The final model, the Cold and Icy Model, states that early Mars was cold and ice covered, and the occasional melting of snow created the fluvial features.
The Wet and Warm Model has the best explanation for how the features were formed, but lacks to properly explain how Mars could reach such high temperatures. The Martian atmosphere would have to have been much thicker to compensate for the younger, colder Sun. The same issue arises for the Cold and Icy Model, as it relies on external forces to melt enough snow to create these features. The source of water and heat in the Episodic Model is easier to explain, but there is doubt that enough rainfall would have occurred to create the large scale valleys networks seen on the Martian surface.