Geologic map of the Oxia Palus Quadrangle of Mars

The Oxia Palus quadrangle contains three distinct geologic provinces: (1) an elevated cratered plateau that occupies three-fourths of the quadrangle and is similar to much of the southern hemisphere of Mars; (2) the low, relatively featureless Chryse Planitia in the northwest corner; and (3) a complex province of chaotic terrain and immense channels or valleys that divides the plateau an determinates at Chryse Planitia. Generally, the oldest geologic units occur in the plateau province and the youngest in Chryse Planitia. Discovery by Mariner 9 of the channels, the four largest of which are given neames meaning Mars in Akkadian, Sumerian, Anglo-Saxon, and Greek (west to east), renews the possibility of water and therefore life on Mars. This possibility may be tested in July 1976 by a landing of the unmanned Viking spacecraft in Chryse Planitia at the mouths of the channels (lat 19.5 degrees N., long 34 degrees).