Reacción a "Mineral in Martian dust changes explanation for why Mars is red and hints at primitive conditions"

The manuscript lacks figures, so I cannot comment on it in more detail. What they tell is very interesting: it is the identification of the presence of ferrihydrite as an important iron mineral on Mars. This gives very important clues about the environmental conditions on early Mars.

Ferrihydrite is very common and can be seen, along with other phases, in any iron material that oxidises, as well as being very common in soils and sediments of rivers or lakes, where it is formed by bacterial activity. Even we generate ferrihydrite, as it is one of the forms in which we store iron: small crystals of ferrihydrite associated with the protein ferritin.

For ferrihydrite to form, you need an oxidising environment and water, which helps to understand the early environment on Mars. Interestingly, ferrihydrite is not stable, and transforms into other minerals, such as haematite or goethite. The preservation of ferrihydrite on Mars also confirms the environmental evolution of the planet: early Mars underwent a transition to today's extremely arid conditions. This surprises me the most, because ferrihydrite is a mineral that forms under very active conditions on Earth. The fact that it has been preserved suggests that Mars was, shall we say, ‘frozen’.

It should be noted that the detection is based on observations from Mars missions and comparison of the data with a series of experiments on the synthesis of ferrihydrite and other minerals, and simulation of the dust on the Martian surface. This finding would need to be confirmed in the future by direct analysis of the mineral.