Before you is an exposition of a thin layer of Martian rock, including tiny crystal-like protuberances, as well as mineral veins with bright and dark material. The rock was called Jura and was observed in the camera MAHLI on the rover Curiosity (January 4, 2018)
The attention of the Curiosity rover was attracted by the dark marks in the thin, bright rock of the Martian ridge. This set of forms is familiar to geologists studying crystals of gypsum created in dry terrestrial lakes. But the scientific team of the rover is considering various possibilities for the appearance of these features on the ridge of Vera Rubin.
Among the uncertainties identified by the rover survey, is the time during which crystalline objects form in relation to the accumulation gap in them of sedimentary layers. In addition, it is important to understand whether the original material remains inside. Answers can indicate the presence of a dried lake or groundwater.
Scientists are considering other clues to learn more about the past of the Red Planet. Among them are rod-shaped elements the size of rice grains, mineral veins with bright and dark areas, color variations in the rocks, smooth horizontal layers that significantly change the thickness of the layers, and iron content.
The ridge of Vera Rubin stands out as an erosion-resistant line on the northern slope of Mount Eolid within the Gail crater. This point was a planned survey site even before the rover arrived in 2012. The vehicle began to rise to the ridge 5 months ago and has now reached the rise (southern edge). Some local features may be associated with the transition to the next area - Clay Unit. In mid-January, the rover settled on the Jura site to explore the area where, in the photographs, the local gray rock stood out against the background of the red ridge base. Attention attracted tiny V-shape. But the main reason for the study is the color change between areas. Rover managed to find tiny crystals.
These formations reach the size of sesame. Some are single elongated crystals. But most often, two or more merge into a V-shaped pattern or more complex star-shaped configurations. Such signatures are characteristic of gypsum crystals created when salt is concentrated in water (for example, a volatile lake).
The thin layer rock in Jura is believed to be the result of sedimentary accumulation of lakes. But an alternative - formed later in a saline fluid moving through the rock.
Some mountain targets in this area are endowed with two-ton mineral veins, created after the lake sediments hardened in the rock. In the lighter parts is calcium sulfate, and in the dark - iron. Some formations appear darker than gypsum, enriched with iron or empty. This hints that the source material being crystallized could be replaced or removed by the latest effects of groundwater.
For the first time, rod-shaped features were noticed 2 days before the rover approached Jura. All raw images are quickly published online, and some showed findings that caught the attention of the public. There is also an assumption that these are pieces of dark vein material. Scientists are delighted with the V-shaped, as they may indicate the presence of fresh, unsalted water. If you understand how the lake ripening process takes place, then you can determine the principle of changing the environment of the Gale crater. If the crystals did not appear in the evaporating lake, but much later, then it is worth talking about the chemistry of the moist underground environment.
In any of the scenarios, crystals are a new proof of the theory of the constant presence of water and the long-lived habitable environment of the Red Planet. Various variations of iron content, smaller signs and the surrounding rocky rock can provide information about life-friendly conditions.