Check out this cool new improved map of the geologic features of Mars;

• A Beautifully Detailed New Geologic Map of Mars – Science/WIRED
• USGS Scientific Investigations Map 3292: Geologic Map of Mars
• USGS Map 3292 (pdf) 
• USGS Geologic Map of Mars – pamphlet (pdf)

The onslaught of up-close exploration in recent years has yielded a ton of information. The Mars Global Surveyor, Mars Odyssey,Mars Express and Mars Reconnaissance Orbiter missions have pored over the planet’s surface with a bunch of different sensors that can detect everything from the types of minerals present on the surface, to the amount of water vapor in the atmosphere, to the structure of the shallow subsurface. These orbiters showed that much of the planet’s surface is older than scientists thought. The area formed more than 4 billion years ago (the darkest brown on the map) is three times as large. The new map also backs up the idea that Mars was geologically active until recently, and that liquid water once was present on the surface.

Abstract:

This global geologic map of Mars, which records the distribution of geologic units and landforms on the planet’s surface through time, is based on unprecedented variety, quality, and quantity of remotely sensed data acquired since the Viking Orbiters.

These data have provided morphologic, topographic, spectral, thermophysical, radar sounding, and other observations for integration, analysis, and interpretation in support of geologic mapping.

In particular, the precise topographic mapping now available has enabled consistent morphologic portrayal of the surface for global mapping (whereas previously used visual-range image bases were less effective, because they combined morphologic and albedo information and, locally, atmospheric haze).

Also, thermal infrared image bases used for this map tended to be less affected by atmospheric haze and thus are reliable for analysis of surface morphology and texture at even higher resolution than the topographic products.