Perseverance rover makes new discoveries in Lake Zero crater on Mars

(ORDO NEWS) — The rover found that the bottom of the Lake Lake crater is made up of volcanic rocks that have interacted with water.

Scientists were surprised when, in the spring of 2021, NASA’s Perseverance rover began examining rocks at the bottom of Lake Jezero Crater.

There was a lake in the crater billions of years ago, they expected to find sedimentary rocks that were formed when sand and dirt settled in the once aquatic environment.

Instead, they found that the crater floor is made up of two types of igneous rock – one formed deep underground from magma, and the other from surface volcanic activity.

The results of the study are described in four new papers published on Thursday, August 25th. One of them, published in the journal Science, provides an overview of the research conducted by Perseverance at the bottom of the crater before arriving at the ancient Jezero River Delta in April 2022; a second study in the same journal describes characteristic rocks that appear to have formed from a thick layer of magma.

Two other papers, published in the journal Science Advances, detail the unique ways in which a rock-evaporating laser and Perseverance ground-based penetrating radar determined that the crater floor was covered in igneous rocks.

Stone of the Ages

Igenous rocks are excellent time keepers: Crystals in them record information about the exact moment of their formation.

“One of the main values ​​of the igneous rocks we collected is that they will tell us when the lake appeared in Lake.

We know that it appeared there more recently than the igneous rocks of the crater floor formed,” said Ken Farley of the California Institute of Technology, Research Fellow at the Perseverance Project, and Lead Author of the first of a new paper in Science.

“This will answer some important questions: When was the Martian climate favorable for lakes and rivers on the planet’s surface, and when did it change to the very cold and dry conditions we see today?”

However, due to the nature of their formation, igneous rocks are not ideal for preserving the potential signs of ancient microscopic life that Perseverance is looking for.

In contrast, determining the age of a sedimentary rock can be challenging, especially if it contains rock fragments that formed at different times before the sediment was deposited. But sedimentary rocks often form in habitable aquatic environments and better preserve ancient signs of life.

That is why the sediment-rich river delta, which Perseverance has been exploring since April 2022, is so enticing to scientists.

The rover has begun drilling and collecting sediment core samples so that the Mars Sample Return campaign could eventually return them to Earth for study using powerful laboratory equipment too large to be delivered to Mars.

Mysterious rocks formed by magma

A second article published in the journal Science uncovers a long-standing mystery of Mars. Many years ago, Martian orbiters spotted a rock formation filled with the mineral olivine. This formation, approximately 70,000 square kilometers in area, extends from the inner rim of the Lake crater into the surrounding region.

Scientists have come up with various theories as to why olivine is so abundant over such a large surface area, including meteorite impacts, volcanic eruptions, and sedimentary processes.

According to another theory, olivine was formed deep underground from slowly cooling magma – molten rock – and was exposed by erosion over time.

Yang Liu of NASA’s Jet Propulsion Laboratory in Southern California and her co-authors determined that the latter explanation is the most likely. Studying the exposed area, scientists drew attention to the large grain size of olivine, as well as the chemical composition and texture of the rock.

Using the Perseverance Planetary X-Ray Lithochemistry Instrument, or PIXL, they determined that the olivine grain size in the area is between 1 and 3 millimeters much larger than would be expected for olivine that formed in rapidly cooling lava on the planet’s surface.

“Such a large size of crystals and their uniform composition in a particular rock texture require very slow cooling of the environment,” Liu said. “Therefore, most likely, this magma in the Lake did not erupt on the surface.”

Unique scientific instruments

Two Science Advances articles detail the results of scientific instruments that have helped establish that the crater floor is covered in igneous rocks.

These instruments include Perseverance ‘s SuperCam laser and a ground-penetrating radar called RIMFAX (Radar Imager for Mars’ Subsurface Experiment). using a visible light spectrometer to determine the chemical composition of the rock.

During the first 10 months of Perseverance’s stay on Mars, SuperCam recorded 1,450 points, which helped scientists to conclude that igneous rocks at the bottom of the crater.

In addition, SuperCam used near-infrared light – the first instrument on Mars with this capability – to detect that water has altered minerals in the crater floor. However, according to a combination of laser and infrared observations, these changes were not ubiquitous throughout the crater floor.

“SuperCam data suggests that either these rock layers were isolated from Lake Lake water, or the lake existed for a limited time,” said Roger Wiens, SuperCam principal investigator at Purdue University and Los Alamos National Laboratory.

RIMFAX marks another first achievement: Martian orbiters carry ground-based penetrating radars, but before Perseverance, there were no spacecraft on the surface of Mars. From the surface, RIMFAX can provide unprecedented detail and survey the floor of a crater up to 15 meters deep.

His high-resolution “radargrams” show layers of rock unexpectedly tilted underground by 15 degrees. Understanding how these rock layers are ordered could help scientists build a timeline for the formation of Lake Jezero.

“Being the first such instrument to operate on the Martian surface, RIMFAX has demonstrated the potential value of GPR as a tool for subsurface exploration,” said Swain-Erik Hamran,

The scientific team is thrilled with what they have found so far, but even more excited about the upcoming research.”


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