A planet’s historical past is instructed in its historic rock. Earth’s oldest rocks are within the Canadian Defend, Australia’s Jack Hill, the Greenstone Belts in Greenland, and a handful of different places. These rocks maintain highly effective clues to our planet’s historical past. On Mars, the identical holds true.
That’s why NASA’s Perseverance rover is revisiting a few of them.
Perseverance is exploring Jezero Crater, an historic paleolake. Its thick layer of sediments could include proof of historic life on Mars. Each crater has a rim, and Perseverance’s present marketing campaign includes finding out the rim. The crater rim is completely different than the sediments. It’s made from historic rock uplifted and uncovered on the floor by the traditional influence that created Jezero.
On Earth, geologists usually research rock that has made itself simple to look at by developing from the deeper crust and presenting itself. The identical factor occurs on Mars, although impacts do the lifting, not plate tectonics. Perseverance is finding out the rocks on the crater rim in its present Crater Rim Marketing campaign. The situation it’s exploring is an uncovered outcrop named Tablelands.
One kind of rock that may educate us rather a lot about Mars’ historic historical past is serpentine. It’s widespread on Earth and Mars and varieties within the presence of water. Its presence on Mars is a few of our strongest proof that the planet was as soon as moist.
Perseverance sampled Silver Mountain, a rock within the Tablelands. The rover used its abrasion instrument on its robotic arm to create a contemporary floor it might analyze. That evaluation confirmed Silver Mountain is wealthy in pyroxene, a sort of silicate present in virtually each igneous and metamorphic rock. The rover additionally collected a core.
After that, it visited a rock named Serpentine Lake that confirmed telltale indicators of serpentine. Perseverance used its abrasion instrument to scrub the rock for an in depth investigation. Serpentine Lake has an intriguing texture, described in a press launch as “cookies and cream.” It’s additionally excessive in serpentine and different minerals that type within the presence of water.
After that, Perseverance doubled again to revisit a rock named “Cat Arm Reservoir.”
It was the primary rock the rover studied on the canyon rim. The rover analyzed its composition and detected coarse pyroxene and feldspar crystals, indicating an igneous origin. Sadly, Perseverance’s pattern tube was empty. Typically, the rock the rover tries to pattern is weak and turns to mud. That is uncommon, nevertheless it did occur through the rover’s very first sampling attempt, and it occurred once more with Cat Arm Reservoir.
Perseverance travelled a small distance and tried to gather a core pattern from Cat Arm Reservoir once more. That try additionally failed. Then the rover selected a unique spot close by named “Inexperienced Gardens” and efficiently collected a core pattern. It’s subsequent to the abrasion patch on Serpentine Lake.
Just like the Serpentine Lake rock, Inexperienced Backyard can also be inexperienced, which is a attribute of the mineral serpentine. Serpentine varieties within the presence of water when hydrothermal vents alter ultramafic rocks. Scientists are excited by these minerals as a result of their construction and composition can reveal the historical past of water on Mars. On Earth, serpentine rock additionally hosts microbial life, so the identical could have been true on Mars. Sadly, it’s not clear how a lot evidence of this life can be preserved.
Perseverance will spend some extra time exploring the Tablelands outcrop. It could re-examine the Serpentine Lake abrasion patch and analyze the particles from the Inexperienced Gardens drilling and coring. This might take a few weeks.
Subsequent on its agenda is “Broom Level,” additional down the crater rim. Broom Level accommodates a spectacular formation of layered rock, which can also be intriguing to scientists.
Mars’ historic historical past is instructed in its historic rocks, nevertheless it’s inconceivable to know upfront which rock holds which clues and the way every thing will fall into place.
We don’t know what Perseverance will uncover about Broom Level. However the rock will inform us one thing. It at all times does.
