Amphitrites Patera

A color image of the Amphitrites Patera region of Mars; north toward top. The scene shows several indistinct ring structures and radial ridges of an old volcano named Amphitrites Patera. A patera (Latin for shallow dish or saucer) is a volcano of broad areal extent with little vertical relief.

This image is a composite of NASA's Viking medium-resolution images in black and white and low-resolution images in color. The image extends from latitude 55 degrees S. to 62 degrees S. and from longitude 292 degrees to 311 degrees; Lambert projection.

Amphitrites Patera is a 138-km-diameter feature on the south rim of Hellas impact basin and is one of many indistinct ring structures in the area. The location of the paterae in this area of Hellas indicates that their source magma may have been influenced by the transition fractures of the basin. The radial ridges of Amphitrites extend for about 400 km north into the Hellas basin.

http://photojournal.jpl.nasa.gov/catalog/PIA00410