From Exodus3000 Wiki

Argyre Planitia is a plain located in the Argyre impact basin in the southern highlands of Mars. The basin is approximately 1120 miles (1800 Km) wide and drops 3.2 miles (5.2 Km) below the surrounding plains. This basin was possibly formed by a giant impact during a Heavy Bombardment Period of the early Solar System, approximately 3.9 billion years ago. It is believed to be the second-largest impact basin on Mars after Hellas Planitia, and may be one of the best preserved ancient impact basins from that hypothetical event.

The original basin floor is buried with friable, partially deflated layered material that may be lake sediment.

Argyre Planitia's name refers to Argyre, a mythical island of silver in Greek mythology.

Argyre Planitia viewed on Google Mars

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