Believed to be mostly composed of basalt and basaltic andesite, its sides average a slope of 4 degrees.  
It includes the craters Pangboche and Karzok, and was described by the term "Nix" before its true nature was confirmed.  Largely formed during the Noachian Epoch, it is northwest of three similar features named (*) Pavonis, Arsia, and Ascreus.   Believed to be mostly composed of basalt and basaltic andesite, its sides average a slope of 4 degrees.  Owing its overall size to the lack of continental drift, it is surrounded by a scarp approximately 550 kilometers in diameter, and also features a 70-kilometer diameter caldera. Located on the Tharsis Bulge, for 10 points, name this feature, a 27-kilometer shield volcano on the surface of Mars.
It includes the craters Pangboche and Karzok, and was described by the term "Nix" before its true nature was confirmed.  
{Olympus Mons} (1) [AU]