July 24, 2025, at 4,609ᵉ Martian day of the mission, the Rover Curiosity captured an intriguing image of an eroded rock, with the appearance of a coral, using the micro -imaging remote integrated into its chemcam instrument.
This type of training, which Curiosity meets regularly, testifies to an ancient history on Mars, where liquid water interacted with the rock long before the wind was in play.
Structures born of water, shaped by time
This rock, similar to others observed by the rover, has a double origin: water and wind. It is a dynamic well known to geologists. At the time when Mars still housed liquid water, dissolved minerals were transported in the cracks in the rock by aqueous circulation. Once the water is evaporated, the mineral deposits remained trapped in the matrix.
It was these hardened areas that have resisted billions of years of erosion by Martian windswhile the surrounding rock has gradually disintegrated.
A morphology that is not random
The forms observed here are similar to coral and do not come from the visual coincidence. The process highlighted is recurrent on Mars, just like on earth: a differential of mechanical resistance between mineralized areas and the host rock allows the appearance of complex figures. Among them, certain training courses even evoke flowers, already documented by Curiosity.
Chemcam’s eye, the fruit of international cooperation
Chemcam’s micro -imaging remote, used to capture this image, results from a collaboration between Los Alamos National Laboratory and several French institutions : CNES, University of Toulouse and CNRS.
Developed by the JPL (Jet Propulsion Laboratory) of NASA, under the supervision of the Caltech in Pasadena, Curiosity is led within the framework of the Mars Exploration Program.
This transatlantic cooperation makes it possible to analyze with finesse structures at a distance, without physical contactbut with precision compatible with advanced mineralogical objectives.
A terrestrial resurgence on extraterrestrial soil
This mineralization phenomenon followed by differential erosion is not specific to Mars. It is documented in many terrestrial geological contexts, especially in desert environments, where the wind plays a major role in the disintegration of the rocky masses exposed.
In the absence of current water, the wind remains on Mars the dominant agent of surface remodeling. It reveals, by digging, the internal structures of ancient rocks, today allowing instruments like those of Curiosity to read geochemical processes of several billion years old.
A stratigraphic reading on a grain scale
The details captured by Mars Hand Lens Imager, Confirming the observations of the micro imaging remoteshow that even on a millimeter scale, the contrasts between consolidated areas and more brittle areas are clear.
It is this difference in behavior under wind constraint which gives the training their singular appearance. The process is reproducible, observable, and now well characterized thanks to the data accumulated by the rover.
One more example in the Mars Geological Atlas
This new image is not an isolated casebut an occurrence among others, which is part of a coherent set of data collected for more than twelve years. Each fragment observed, each eroded motif completes the paleohydrological reading of Mars.
What we see today as an aesthetic form is actually a precious indicator of the old conditions of transport, precipitation and mineral alteration.
The importance of time and wind
Without water, without vegetation, without active tectonicsMars remains a frozen planet, where the wind acts alone, slowly but tirelessly. He erases, he reveals, he sculpts. The forms thus produced are as many delayed signatures of a wet past. Curiosity archives them, deciphers them, transmits them.
And this coral -shaped rock is only one example among many others.
Source of the article: https://www.jpl.nasa.gov/images/pia26634-curiositys-chemcam-views-a-rock-shaped-like-coral/
Credit : NASA/JPL-Caltech/LANL/CNES/CNRS/IRAP/IAS/LPG
