In August 2012, the Mars Science Laboratory’s rover Curiosity landed at the base of Gale crater, a 5-kilometer-high mountain that formed when a meteor hit Mars billions of years ago. Using its 2-meter-long arm to drill into the planet’s surface, Curiosity scooped up and analyzed rock and soil samples, including some light-colored, crystal-studded rocks surprisingly similar to the ancient granitic rock that forms much of Earth’s continental crust.
The discovery made waves in the science community because it suggested that Mars might be the only known planet besides Earth possibly to have a continental crust. Mars traditionally is thought to be covered in denser, darker igneous rock similar to Earth’s oceanic crust, which is formed as volcanic magma sourced from Earth’s mantle cools.
Now, however, research [published in the Journal of Geophysical Research] by Arya Udry et al. contradicts that hypothesis. Instead of seeping up between tectonic plates, the team argues, the rocks could have formed through a process similar to one on Earth: intraplate, or “hot spot,” volcanism, found in places like Hawaii, Iceland, and the Canary Islands. In hot spot volcanism, magma does not need to find the boundaries or cracks between tectonic plates to rise to the surface. Instead, it merely pushes up and breaks through weaker, thinner areas of crust… [More at links]