Pure quartz crystals have been spotted on Mars for the first time, as well as other gems like opal. Researchers say these crystals, as well as being evidence of past hydrothermal activity, could contain well-preserved signs of ancient Martian life.
Since it arrived on Mars in 2020, NASA鈥檚 Perseverance rover has been scouring the bottom of Jezero crater, a vast ancient lake probably formed by an asteroid impact. But last year, the rover journeyed out of the lake bottom and began climbing the crater鈥檚 rim, where the rocks and geology are different.
at Grenoble University in France and his colleagues analysed the pictures that Perseverance took with its SuperCam instrument. They found large, centimetre-wide quartz, a crystal made from silicon, as well as other silicon-containing crystals like opal and chalcedony, which must have formed in the presence of ancient hot water.
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The data from SuperCam also enabled the team to analyse the spectrum of light reflected by the rocks. This showed that the quartz crystals had a high purity, with less contamination from other compounds than any other rock that Perseverance had seen. 鈥淲e are looking at a fairly large crystal size, and in fact, a very pure type of quartz,鈥� Beck told the Lunar and Planetary Sciences Conference in The Woodlands, Texas, on 10 March.
The only way we know how to form such large, pure quartz crystals on Earth is from complex hot-water systems, which suggests a similar origin on Mars, said Beck. These crystals could have formed after the initial impact that created the Jezero crater, when hot water flowed through the cracked rocks and interacted with churned-up material from the asteroid explosion.
Quartz is also useful as a record of ancient life, which scientists have used as a reference on Earth, said Beck. 鈥淲e can see biosignatures that are more than 3.5 billion years old, and the reason we can look at them on Earth is because these biosignatures are preserved in a silicon matrix, which is a very efficient preserve of morphological or molecular signatures,鈥� said Beck. 鈥淪o this is clearly a high-value target for a Mars sample return mission.鈥�
Earth and Planetary Science Letters
