Exploring the Red Planet’s Past: Perseverance Finds Clues on Martian Riverbanks

The latest images captured by NASA’s Perseverance rover on Mars are revealing a fascinating new understanding of the planet’s ancient environment. In particular, scientists are excited about evidence suggesting the presence of a powerful river network in the Jezero crater that could provide clues to the existence of ancient microbial life on the Red Planet. These findings are thanks to new mosaics created from hundreds of images taken by the rover, which reveal large sediment grains and boulders indicating a river that was capable of carrying a significant amount of debris. This newfound understanding of Mars’ geologic history is shedding light on the planet’s potential for habitability and could have significant implications for future exploration.

Perseverance’s Discoveries Prompt Reconsideration of Martian Environment

The evidence gathered by Perseverance on Martian rocks is prompting scientists to reconsider their understanding of the ancient Martian environment.

Recently acquired images by NASA’s Perseverance rover suggest the presence of a once-turbulent river on the Red Planet. Initial images of the ancient Martian riverbed have revealed the water to be significantly deeper and faster than scientists previously believed. The river was just one component of a network of waterways that converged in the Jezero crater, the area which the rover has been exploring for over two years since its landing.

This newfound understanding of the Martian environment is critical for scientists in their search for potential signs of ancient microbial life, which could have been preserved within the planet’s rocky terrain.

Examining Martian Sedimentary Rock with Perseverance

Perseverance is currently exploring the summit of a towering, fan-shaped sedimentary rock pile that stands 250 meters high. The curved layers present in the rock strongly suggest the presence of flowing water at some point in the distant past. Scientists are now investigating whether this water flowed through shallow streams, similar to what was discovered by NASA’s Curiosity rover in the Gale Crater, or through a more powerful and dynamic river system.

Mosaics Provide Clues to Martian Geologic History

Thanks to two new mosaics created from hundreds of images captured by Perseverance, scientists now have a clearer picture of the environment and the presence of a powerful river. The mosaics reveal significant clues, such as the presence of large sediment grains and boulders, indicating a river that was capable of carrying a large amount of debris. This phenomenon is well-known and studied on Earth, and its occurrence on Mars provides new insights into the planet’s geologic history.

Curvilinear Unit: A Unique Feature of the Jezero Crater

In the past, scientists had observed a series of curved bands of stratified rock within the Jezero crater, which they referred to as the “curvilinear unit.” While visible from space, Perseverance is now providing the opportunity to study these layers up close.

One area within the curvilinear unit, dubbed “Skrinkle Haven,” has been captured in a new mosaic created by the rover. The distinctive curved layers were clearly formed by a significant amount of flowing water, though detailed images have sparked a debate regarding the river’s type.

When viewed from the ground, the curved layers appear to be arranged in rows that ripple through the landscape. They may be the remains of riverbanks that have shifted over time or of sandbars that have formed in the riverbed itself. The layers were likely much taller in the past. Scientists suspect that after these mounds of sediment turned into rock, they were sandblasted by the wind over millennia and carved down to their current size.

The wind acted like a scalpel that sliced off the tops of these deposits. Such features have also been observed on Earth, but they are never as well exposed as they are on Mars. Earth is covered in vegetation that hides these layers.

Unusual Sedimentary Layers at Pinestand

A second mosaic captured by Perseverance shows a separate location that is part of the curvilinear unit about 450 meters from Skrinkle Haven. “Pinestand” is an isolated hill with sedimentary layers that curve toward the sky, some as high as 20 meters. Scientists believe that these tall layers may also have been formed by a powerful river, although they are considering other explanations as well.

These layers are unusually tall for rivers on Earth, but at the same time, the most common way to create this type of morphology is the presence of a river.

Looking Beneath the Surface with RIMFAX

The team is continuing to study the images to discover further clues, data that is combined by looking beneath the surface thanks to Perseverance’s radar instrument called RIMFAX (short for Radar Imager for Mars’ Subsurface Experiment). What they learn from both tools will contribute to an ever-expanding knowledge of Mars’ ancient watery past. It is the first time that scientists have observed this kind of rivers on Mars, and this is leading to the possibility of having them on a larger scale than before.

Credit:NASA/JPL