What Curiosity tells us about the composition of Martian soil

Since 2012, Curiosity surveys the floor of Gale Crater on Mars In order to understand the past environment of Mars. After studying the fluvio delta and . sediments Lake From Aeolis Palostake care of curiosity geology From Aeolis Mons, the building, which has a height of 5500 meters and is located in the center of the crater. Since 2019, it’s now in an area called Glen Torridon, which corresponds to a small ravine that cuts the side ofAeolis Mons. This area is of particular interest to scientists because of the suspected presence of metal muddy. However, the mud known on earth as Promote the preservation of organic matter. So Glenn Torridon would be an ideal area to search for the possible presence of ancient biomarkers. But the interest of scientists goes further. This slurry unit will already be covered with a sulfate-rich unit. This metallic and stratified transition could indeed be a sign of a major modification of Atmosphere Mars, which would have occurred around the Noachian-Hesperian transition (about 3.5 billion years ago). So it seems that Glen Torridon soil analysis is essential for understanding Mars’ past and evolution.

The floor of Gale Crater was definitely a lake

So he used curiosity as his tool ChemCam To analyze the composition of the soil in this area. Thus, the rover seeks to determine the presence of many minerals that it containsOxygen (SiO₂TiO₂AlO₃iron O_TMgO, CaO, Na₂O and K.₂Q) as well as others chemical elements. The chemical weathering index was also estimated for each sample.

The results of mineral analyzes published in the journal JGR- Planetsturns out that Layers The mud that the rover examined in Glenn Torideon was definitely checked under several hundred meters sediment, which could later be removed by erosion to obtain the current landscape of Aeolis Mons. Some mud deposits indicate that they were deposited In a calm lake environmentwhile others feature a more dynamic environment, such as the banks of a river or lake.

The presence of water in each stage of sediment formation

The data also allows to trace the history of chemical weathering at Glen Torridon. High values ​​of the chemical weathering index indicate that the oozes were weathered by water and that the amount of water was remarkably sufficient to allow complete decomposition of certain elements, such as calcium. This episode of chemical change by water would have occurred early in the sediment’s history, before, during, or after its transport and deposition in Bottom of Gale Crater. After their deposit, the process sweating (scaling sediment) accompanied by fluid circulation. The effect of fluid circulation after the sweating process is also proven.

However, it appears that the amount of mud is not higher than in other parts of the crater, as suggested by orbital measurements made by analysis deviation X-ray This result is important because it allows a better interpretation of the signal that is observed fromorbiting By the track tool, especially for future measurements at other locations. It therefore appears that orbital measurements are not solely controlled by the abundance of clay minerals as previously thought.