A study performed by researchers at UCLA and the University of Oslo has revealed surprising findings from the Perseverance Rover that illustrate the enigmatic history of Mars.
The Perseverance Rover first landed on the red planet – Earth’s closest planetary neighbour – a year-and-a-half ago to explore Mars for evidence of ancient life and vital information about its geological and climatic past.
Now, a paper titled “Ground penetrating radar observations of subsurface structures in the floor of Jezero crater, Mars,” illustrates the first data from Perseverance.
Examining the Jezero crater
Perseverance is comparable to the size of a car and is equipped with a multitude of scientific instruments. The Rover has been probing Mars’ 30-mile-wide Jezero crater, which many moons ago hosted a Martian lake, making it a prime candidate to explore for signs of ancient life.
Currently, the Perseverance Rover is analysing a delta on the western edge of the crater, where a river once meandered and supplemented the lake, leaving behind substantial deposits of dirt and rocks it accumulated along its course. The researchers are hoping that as the Rover gathers more data, they will be able to piece together the complex history of Mars.
Surprising Perseverance Rover data
Exciting new data obtained with the Perseverance Rover’s ground-penetrating radar instrument has illuminated that the rock layers beneath the Jezero crater’s floor are unexpectedly inclined. The slopes, thicknesses and shapes of the inclined sections indicate they were formed by slowly cooling lava or deposited as sediments in the former lake.
David Paige, a UCLA professor of Earth, planetary and space sciences and one of the lead researchers on the Radar Imager for Mars Subsurface Experiment (RIMFAX), commented: “We were quite surprised to find rocks stacked up at an inclined angle.
“We were expecting to see horizontal rocks on the crater floor. The fact that they are tilted like this requires a more complex geologic history. They could have been formed when molten rock rose up towards the surface, or they could represent an older delta deposit buried in the crater floor.”
The researchers explained that the Perseverance Rover evidence suggests an igneous or molten origin. However, based on the RIMFAX data, they cannot determine how the inclined layers formed for certain.
RIMFAX acquires a picture of underground features by emitting bursts of radar waves below the surface, which are reflected by rock layers and other obstacles. These shapes, densities, angles, thickness and compositions of these underground objects affect how the radar waves bounce back, creating a visual image.
Throughout the first 3-kilometre traverse of the Rover, the instrument obtained a continuous radar image of the electromagnetic properties and bedrock stratigraphy of the crater’s floor to depths of 15 meters.
The image identified the presence of ubiquitous layered rock strata, including those inclined up to 15 degrees. Additionally, the team discovered highly reflective rock layers that tilt in multiple directions.
Paige explained: “RIMFAX is giving us a view of Mars stratigraphy similar to what you can see on Earth in highway road cuts, where tall stacks of rock layers are sometimes visible in a mountainside as you drive by. Before Perseverance landed, there were many hypotheses about the exact nature and origin of the crater floor materials. We’ve now been able to narrow down the range of possibilities, but the data we’ve acquired so far suggest that the history of the crater floor may be quite a bit more complicated than we had anticipated.
“RIMFAX is giving us the backstory of the samples we’re going to analyse. It’s exciting that the Rover’s instruments are producing data, and we’re starting to learn, but there’s a lot more to come. We landed on the crater floor, but now we’re driving up on the actual delta, which is the main target of the mission. This is just the beginning of what we’ll hopefully soon know about Mars.”
