NASA ROVER FINDS MARS ROCKS INTERACTED WITH WATER THREE TIMES

NASA's Perseverance rover has found evidence that rocks in Mars' Jezero Crater interacted with water on at least three separate occasions, according to a study published in the journal Communications Earth & Environment. The rover reached the inner rim of the crater, an area known as the Margin Unit, in September 2023. Scientists had expected to find sedimentary rock built up along the edge of what was once an ancient lake. Instead, Perseverance encountered igneous rock, which forms either from magma deep underground or from volcanic activity at the surface. Researchers said each of the three water episodes altered the rock's chemistry and physical appearance in a different way.

Scientists had been drawn to the Margin Unit partly because Mars orbiters had detected strong carbonate signatures there from above. On Earth, carbonate minerals typically form in shallow lakes and oceans, environments capable of supporting life, and sedimentary rocks made of clay and silt can preserve evidence of past microbial activity particularly well. Much of the new evidence came from SuperCam, an instrument mounted on Perseverance's mast that identifies minerals by analysing light reflected from Martian rocks. SuperCam can also fire a laser at a target from as far as 21 feet (6.5 metres) away, briefly turning a small amount of rock into plasma for analysis. Researchers noted that igneous rock, unlike sedimentary rock, preserves unusually detailed records of the conditions under which its crystals formed.

According to the findings, the water episodes recorded within the rocks included groundwater, a lake, and later hot fluids moving through the Martian subsurface. Researchers said the rock's crystal structures allowed them to distinguish between these separate periods when water was present at the site. The study adds to scientific understanding of how water moved through Jezero Crater over time, beyond the lake environment that originally drew NASA's interest to the Margin Unit. Researchers described the region's geological history as more complex than scientists had anticipated before Perseverance's arrival.