Russell (Martian crater)
The Russell Crater dune field is covered seasonally by carbon dioxide frost. Numerous dark dust devil tracks can be seen meandering across the dunes.
|Eponym||Henry Norris Russell, an American astronomer (1877-1957)|
Russell Crater is a crater found in the Noachis quadrangle of Mars located at 54.9° south latitude and 347.6° west longitude. It is about 139.7 km in diameter and was named after Henry Norris Russell, an American astronomer (1877-1957). Debris flows have been observed on some of the dunes in this crater. Some researchers believe that they may be caused by liquid water. Liquid water could be stable for short periods of time in the summer in the southern hemisphere of Mars. These gully-like debris flows may be due to small amounts of ice melting. Another idea is that chunks of dry ice form on the dunes during the cold winter, then slide down in the spring when it is warmer. Experiments have demonstrated that carbon dioxide from the thawing dry ice forms a lubricating layer under pieces of dry ice, making it easy for the process to take place.
Why are Craters important?
The density of impact craters is used to determine the surface ages of Mars and other solar system bodies. The older the surface, the more craters present. Crater shapes can reveal the presence of ground ice.
The area around craters may be rich in minerals. On Mars, heat from the impact melts ice in the ground. Water from the melting ice dissolves minerals, and then deposits them in cracks or faults that were produced with the impact. This process, called hydrothermal alteration, is a major way in which ore deposits are produced. The area around Martian craters may be rich in useful ores for the future colonization of Mars.
Dust devil tracks
Many areas on Mars experience the passage of giant dust devils. A thin coating of fine bright dust covers most of the Martian surface. When a dust devil goes by it blows away the coating and exposes the underlying dark surface. Dust devils have been seen from the ground and high overhead from orbit. They have even blown the dust off of the solar panels of the two Rovers on Mars, thereby greatly extending their lives. The twin Rovers were designed to last for 3 months; instead they have lasted more than five years and are still going. The pattern of the tracks have been shown to change every few months. The image below of Russell Crater shows changes in dust devil tracks over a period of only three months, as documented by HiRISE.
Russell Crater dust devil changes, as seen by HiRISE. Click on image to see changes in dust devil tracks in just 3 months.
- "Gazetteer of Planetary Nomenclature | Russell". usgs.gov. International Astronomical Union. Retrieved 4 March 2015.
- Reiss, D, R. Jaumann. 2003. Recent debris flows on Mars: Seasonal observations of the Russell Crater dune field. Geophysical Research Letters: 30, 1321.