Surface features of Venus

The surface of Venus is dominated by geologic features that include volcanoes, large impact craters, and aeolian erosion and sedimentation landforms.

Studies of the Venusian surface are based on imaging, radar, and altimetry data collected from several exploratory space probes, particularly Magellan, since 1961 (see Venus Exploration).

Although much older than Earth's, the surface of Venus is relatively young compared to other terrestrial planets (<500 million years old), possibly due to a global-scale resurfacing event that buried much of the previous rock record.

Structurally, these plains contain features such as wrinkle ridges, grabens (fossa and linea), fractures, scarps (rupes), troughs, hills (collis), and dikes in both local and region scales.

However, because of the high surface temperature of Venus, liquid water is unstable, making their comparison with terrestrial rivers difficult.

When compared to Earth, the number of preserved volcanic zones is staggering, and this is based on Venus' strong crust due to a lack of water.

These tend to occur in mid to upper altitudes, where rifting and extension are common, and they signal mantle upwellings to the surface.

[9] Volcanic centers on Venus are characterized in two main categories based on the ability or inability to create a shallow magma reservoir: Large flows originating from a single edifice or extensive regions with many small eruption sites clustered together.

Rift-dominated rises are uplifted by rifting and thinning of the lithosphere and include the Beta Regio and the overlying Theia Mons.

In a coronae-dominated rise, uplift is caused by the gravitational collapse and extension of a magma chamber, and include the Themis Regio.

[9] Tesserae are a feature unique to Venus and are characterized as continent-sized regions of high topography (1 to >5 km above the datum) that are heavily deformed, often with complex patterns of ridges.

However, unlike some planets in our system, Venus' thick atmosphere creates a strong shield that decelerates, flattens, and can fracture incoming projectiles.

Depending on the angle of impact, velocity, size, and strength of the approaching body, the atmosphere may tear and crush the projectile, essentially melting it in the air.

The atmosphere can flatten and slow larger meteoroids to terminal velocity and cause them to explode on impact or near the surface, showering the region in debris.

[14] Recent Magellan images show over 6,000 aeolian landforms, including dunes (or undae), windstreaks, and yardangs.