In ancient times there was a dynamic environment in Gale Crater on Mars

NASA has provided an update of its Mars Rover Curiosity’s activities in what was called a clay-bearing unit of ​​Mount Sharp on Mars. Clay is associated with water, so the goal of current research is to offer new information to reconstruct the history of Mars, in this case of Gale Crater, where in ancient times there was a lake and now there’s Mount Sharp. Lately, Curiosity has been working near an outcrop that was named “Teal Ridge” and near a rock that was named “Strathdon”, formed by dozens of sedimentary layers that suggest a more dynamic environment than other typical lake sediments.

In April 2019 the Mars Rover Curiosity reached the clay area called Aberlady, where it begun its sampling and examination of rocks, helped by the fact that they turned out to be quite friable. The presence of clay minerals was detected thanks to surveys conducted by the Mars Reconnaissance Orbiter (MRO) space probe but it took almost seven years of travel for Curiosity to reach that area.

Kristen Bennett of the U.S. Geological Survey, co-leader of the clay-unit campaign, stated that it’s one of the reasons Gale Crater was chosen. However, a mystery emerged when the Mars Rover Curiosity discovered amounts of clay minerals among the highest in the mission in some parts of Mount Sharp indicated by the MRO but also in others where the space probe hadn’t detected them.

Valerie Fox of Caltech, the other campaign co-leader, explained that the Mars Rover Curiosity found a lot of gravel and pebbles when it entered the area and they could be the key to solving the mystery. The pebbles could collectively appear as a single clay signal for MRO. Even dust could contribute to the differences in the surveys by preventing the detection in flat areas, where it settles more easily than on the pebbles. Unfortunately, the pebbles were too small to drill them so scientists are looking for other clues.

During its work in the area, the Mars Rover Curiosity passed near an outcrop named “Teal Ridge” and subsequently studied a rock named “Strathdon”, which turned out to be very interesting due to its layers’ characteristics. Curiosity already studied other rocks associated with sediments of the ancient lake that existed in Gale Crater that had thin and flat layers. Instead, the dozens of Strathdon layers got hardened into a brittle, wavy heap. This suggests a more dynamic environment than a simple lake in which there may have been winds, water flows or both.

The top image (NASA/JPL-Caltech/MSSS) shows a 360° panorama of Teal Ridge. The image right above (NASA/JPL-Caltech/MSSS) shows the Strathdon rock with details of various layers in the bottom image (NASA/JPL-Caltech/MSSS).

Valerie Fox pointed out that both Teal Ridge and Strathdon represent changes in the landscape with an evolution in the ancient lake environment recorded in the rocks. There wasn’t a linear transition from wet to dry but rather a more complex history that still has to be reconstructed.

On the 7th anniversary of its landing on Mars, the Mars Rover Curiosity continues its research on Mount Sharp bringing new information on the history of the entire Gale Crater. It’s a complex history that went through various stages that can give an idea of ​​how Mars changed since the ancient era when it was much more like Earth.

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