The highlands of Venus are large elevated regions over 1000 km across that display the most diverse and extensive volcanic and tectonic features on the planet's surface. The unprecedented details of surface tectonics and volcanism revealed by the Magellan mission have added significantly to our understanding of how these continent-sized regions formed, and shed new light on the tectonic style and interior dynamics of Earth's sister planet. Comparisons between the two planets may help us to better understand how plate tectonics began and how the process operates on Earth.
Venusian highlands fall into two distinct categories: volcanic rises and plateaushaped highlands. Volcanic rises were relatively well-understood even before Magellan, although the new images and gravity data will illuminate more of the details of these features. The volcanic rises appear to be the result of large upwellings of hot, buoyant material from deep within Venus' mantle. The upwellings may take the form of mantle plumes, which on Earth are responsible for hotspot features such as the Hawaiian-Emperor seamount chain and Iceland.