A rock is intriguing scientists on Mars. The Perseverance rover has discovered a unique striped formation in the Jezero crater.
This 8-inch (20 cm) block, named "Freya Castle," is raising questions about its origin. Why is it there, isolated, in the middle of the Martian terrain?
The discovery of this striped rock marks a new milestone in Mars exploration. Perseverance is climbing the slopes of the crater, searching for ancient rocks, but this find stands out.
NASA's Perseverance Mars rover captured this image of a black-and-white striped rock using its left Mastcam-Z camera. Mastcam-Z is a pair of cameras located on the rover's mast. This image was acquired on September 13, 2024 (Sol 1268) at local mean solar time 12:40:29.
NASA/JPL-Caltech/ASU
The first images of Freya Castle were sent back by the Mastcam-Z camera. They revealed a rock with contrasting black and white patterns, an appearance visually distinct from the other formations in Jezero. This rock could be igneous or even metamorphic.
Researchers hypothesize that this unusual rock could have much deeper origins within the Martian crust. Indeed, the striped texture observed on its surface may result from complex and varied geological processes. Among these processes, magma crystallization stands out, a phenomenon that occurs when magma cools slowly, allowing crystals to form and arrange themselves in distinct layers. Simultaneously, a transformation under pressure could also play a critical role, where preexisting rocks undergo mineralogical changes due to increased pressure and temperature, leading to the emergence of this peculiar striped structure.
The rock seems to have been transported, perhaps from a higher elevation. This phenomenon intrigues researchers, who hope to find other similar formations to better understand these origins.
Freya Castle is not the only intriguing rock recently discovered on Mars' surface. Indeed, near "Mount Washburn," the Perseverance rover also spotted a collection of boulders of great diversity. This variety of rock formations may indicate that ancient layers, once buried in the Martian crust, were exposed due to tectonic forces generated by the impact that formed the Jezero crater. These observations raise the possibility that the site houses valuable samples of Mars' geological history, thus providing clues about the conditions that prevailed there in the distant past.
With its discoveries, the Perseverance rover continues to unveil the buried mysteries of Mars. Each rock and formation adds a new piece to the puzzle in retracing the geological history of the planet. The Perseverance mission is far from over. By reaching new heights, the team hopes to uncover Mars' mysteries and perhaps, one day, discover traces of ancient life.
What is a metamorphic rock?
Metamorphic rocks form when preexisting rocks, called protoliths, undergo transformations due to heat and pressure. This process, known as metamorphism, can alter the mineral composition and texture of the rock, making the metamorphic rock different from its original form.
This process generally occurs in geological environments like mountain ranges, where tectonic forces can bury rocks to significant depths. Under high temperatures and increased pressures, chemical reactions can take place, leading to the formation of new minerals and the appearance of various structures.
Metamorphic rocks are important for understanding the geological history of a region because they retain traces of the pressure and temperature conditions they were subjected to. For example, studying the composition and structure of these rocks can offer clues about tectonic events and environmental changes that have impacted the Earth's crust over time.
Article author: Cédric DEPOND