NASA’s Perseverance rover on Mars, which is examining the rocks on the floor of Jezero Crater of the Red Planet, has found out that the floor is composed of two types of igneous rock, contrary to the scientist’s expectation of sedimentary rock, NASA reported on Thursday. Although a detailed study of the rocks is warranted, that can happen only after a decade when the samples return to earth. The scientists believe that this is already a ground breaking discovery.
The findings which were published in four recent papers in the journal Science and Science Advances, could offer a good chance for scientists to understand about the geological and water history of Mars. “This will address some major questions: When was Mars’ climate conducive to lakes and rivers on the planet’s surface, and when did it change to the very cold and dry conditions we see today?” NASA quoted Ken Farley of Caltech, Perseverance’s project scientist and the lead author of the first of the new Science papers, explaining about the findings.
Why is this discovery significant ?
The samples collected are of two types of igneous rocks; one that formed deep underground from magma, the other from volcanic activity at the surface. NASA says that the Igneous rocks are excellent timekeepers. It can be used for precise geochronology once they’re returned to Earth. “Crystals within them record details about the precise moment they formed.”
The papers point out that the noteworthy finding shows that the rocks have been altered by water. “One great value of the igneous rocks we collected is that they will tell us about when the lake was present in Jezero. We know it was there more recently than the igneous crater floor rocks formed,” states Farley.
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Why scientists expected sedimentary rocks?
NASA says that as the crater held a lake billions of years ago, they had expected to find sedimentary rock, which would have formed when sand and mud settled in a once-watery environment.
The problem with Igneous rock is it can’t keep the probable signs of ancient microscopic life as better as sedimentary rocks can. Sedimentary rock usually forms in watery environments convenient for life and is better at sustaining ancient signs of life.
However, geochronology of sedimentary rocks is challenging, especially when it contains rock fragments that formed at distinct times before the rock sediment was accumulated, NASA says. Although, the rover has begun drilling and collecting core samples of sedimentary rocks that it might bring back to Earth.
With earlier missions having found the existence of liquid water on Mars in the distant past, the Perseverance exploration of NASA is sent to take the next step by looking for the signs of past life on Mars.
