The Borealis basin covers 40% of this locale, and 
The Borealis basin covers 40% of this locale, and the geologic history of this astronomical body is split into three primary epochs, the Noachian, Hesperian, and Amazonian. It is home to the Valles Marineris, a large canyon, and is the home of the (*) tallest known mountain in the Solar System. This body's soil was sampled in 2008 by the Phoenix lander, and in 2007, compounds containing water molecules were found on this planet by the rover Spirit. For ten points, name this celestial body and site of Olympus Mons, the fourth planet from the sun.
The Borealis basin covers 40% of this locale, and the geologic history of this astronomical body is split into three primary epochs, the Noachian, Hesperian, and Amazonian.
{Mars}