The
north polar residual ice cap of the Planum Boreum region, which
is cut by spiral-patterned troughs, is located at top. The upper
part is marked by large depression, Isidis basin, which contains
light-coloured plains. The upper part also includes the light- colored
smooth plains of Elysium Planitia and dark plains of Vastitas Borealis.
Together, these form a vast expanse of contiguous plains. Toward
the bottom, on the other hand, the southern hemisphere is almost
entirely made up of heavily cratered highlands. Toward the bottom,
a conspicuous, relatively bright circular depression marks the ancient
large Hellas impact basin.
|