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Last updated on June 03, 2019 9:35
Curiosity has now sampled two of the rocks from what NASA calls "the unit containing clay".
(Web Desk) – Clay is a big problem on Mars because it often forms in contact with water. Find clay and you have usually found traces of water. And nature, history, and the current water balance on Mars are all important to understanding this planet and, if so, supporting life.
Currently, MSL Curiosity is at Mt. Sharp inspecting clay in the rocks. The orbiters were the first to find traces of clay at Mount Sharp. When NASA chose Gale Crater as MSL Curiosity's landing site, clay at Mt Sharp inside the crater was one of the goals.
Curiosity has now sampled two of the rocks that NASA called the "clay-containing" unit and confirmed the presence of clay.
In fact, both rocks have the highest clay concentrations that Curiosity has found so far. The rocks are called "Aberlady" and "Kilmarie". They are located in the lower part of Mount Sharp, the main objective of the mission.
Mount Sharp rises 5.5 km above the bottom of the crater, making it a layered record accessible from Martian geology.
Over time, the wind exposed its various layers, making them easy targets for the Curiosity exercise.
Scientists are interested in Mt Sharp, also called Aeolis Mons, because of the way he thinks that it has formed. The crater Gale is an old crater of impact that was probably filled with water and they think that the Mt Sharp has formed over a period of two billion years, because of the fact that sediments were deposited at the bottom of the lake.
It is possible that at some point the crater was filled with sediment, which gradually eroded, leaving Mt Sharp behind.
Some uncertainty surrounds the timeline of Mt Sharp's formation, one of the things MSL Curiosity hopes to discover. Whatever the case may be, Mount Sharp itself appears to be an eroded mountain of sediment and, as Curiosity continues its work, scientists might finally have a more precise idea of how it looks. is formed.
New discoveries at Curiosity show that there was once an abundance of water in the crater of Gale, as expected. But aside from that, the details remain to be determined.
It appears that these clay-rich rocks in the lower part of the mountain have formed sediments at the bottom of a lake. Over geological periods, water and sediments interact to form clays.
Searching for specific types of clays on specific layers informs scientists of the chronology of Martian water. We know that the mountain has different layers containing different minerals.
As mentioned, the lower layers contain clays, but above are layers containing sulfur, and above, layers containing minerals containing oxygen. Sulfur indicates that the area has dried out or that the water has become more acidic.
The Gale crater also contains a river channel called Gediz Vallis Channel, which formed after the layers of clay and sulfur. This channel is also a piece of the puzzle, and the task of Curiosity is to continue its way to Mt Sharp, sampling as and when, and to paint a picture of the geology and history of the mountain. By extension, we will learn something about Martian history.
Curiosity will also give us a much more detailed view of the unit containing clay than that given by the orbiter. The orbital readings were inconclusive as to whether the clay it had detected was in the bedrock of the mountain, or whether it was pebbles and eroded rocks that had eroded from the upper layers from the mountain and collapsed to the floor of the crater. .
Curiosity has clarified this to some extent, with the discovery of clay in Aberlady and Kilmarlie, but there is still much work to be done.
"Every layer of this mountain is a puzzle," said Curiosity project scientist Ashwin Vasavada of JPL. "They each hold clues about a different era of Martian history."
Curiosity does a great job of rebuilding everything.
This article was originally published by Universe today.
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