Janssen Crater is an impact crater in the

Arabia quadrangle The Arabia quadrangle is one of a series of 30 quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Arabia quadrangle is also referred to as MC-12 (Mars Chart-12). The quadrangle contai ...

on Mars at 2.7° N and 322.4° W. and is 154 km in diameter. Its name was approved in 1973, and refers to French astronomer

Pierre Janssen Pierre Jules César Janssen (22 February 1824 – 23 December 1907), usually known as Jules Janssen, was a French astronomer who, along with English scientist Joseph Norman Lockyer, is credited with discovering the gaseous nature of the solar ...

. Some close up images of the crater reveal layers in a floor deposit. A picture below show these layers, as well as

dark slope streaks Dark slope streaks are narrow, avalanche-like features common on dust-covered slopes in the equatorial regions of Mars.Chuang, F.C.; Beyer, R.A.; Bridges, N.T. (2010). Modification of Martian Slope Streaks by Eolian Processes. ''Icarus,'' 205 154 ...

. The darker the streak, the younger it is. The layers on the floor of Janssen may have been formed on the bottom of lakes.Fassett, C. and J. Head. 2008. Open-basin lakes on Mars: Implications of valley network lakes for the nature of Noachian hydrology.

References

Impact craters on Mars Arabia quadrangle {{crater-stub

See also

References