This uniformly layered rock photographed by the Mast Camera (Mastcam) on NASAs Curiosity Mars Rover reveals a pattern typical of a lake-floor sedimentary deposit not far from where flowing water went into a lake. Credit: NASA/JPL-Caltech/MSSS
” We utilized to believe that once these layers of clay minerals formed at the bottom of the lake in Gale Crater, they remained that method, preserving the minute in time they formed for billions of years,” stated Tom Bristow, CheMin principal detective and lead author of the paper at NASAs Ames Research Center in Californias Silicon Valley. “But later brines broke down these clay minerals in some locations– basically resetting the rock record.”
Mars: It Goes on Your Permanent Record
Mars has a treasure trove of extremely ancient rocks and minerals compared with Earth. And with Gale Craters undisturbed layers of rocks, researchers understood it would be an outstanding website to look for evidence of the worlds history, and perhaps life.
Using CheMin, researchers compared samples taken from two areas about a quarter-mile apart from a layer of mudstone transferred billions of years earlier at the bottom of the lake at Gale Crater. Surprisingly, in one area, about half the clay minerals they anticipated to find were missing out on. Rather, they discovered mudstones rich with iron oxides– minerals that offer Mars its characteristic rusty red color.
Researchers understood the mudstones tested had to do with the very same age and started the very same– packed with clays– in both areas studied. Why then, as Curiosity checked out the sedimentary clay deposits along Gale Crater, did spots of clay minerals– and the proof they preserve– “vanish”?
Clays Hold Clues
Minerals are like a time pill; they supply a record of what the environment was like at the time they formed. Clay minerals have water in their structure and are proof that the soils and rocks that include them came into contact with water eventually.
” Since the minerals we discover on Mars likewise form in some places on Earth, we can use what we know about how they form on Earth to tell us about how salted or acidic the waters on ancient Mars were,” said Liz Rampe, CheMin deputy principal detective and co-author at NASAs Johnson Space Center in Houston.
The network of cracks in this Martian rock slab called “Old Soaker” may have formed from the drying of a mud layer more than 3 billion years ago. Credit: NASA/JPL-Caltech/MSSS
Previous work revealed that while Gale Craters lakes were present and even after they dried out, groundwater moved listed below the surface area, dissolving and transferring chemicals. After they were deposited and buried, some mudstone pockets experienced various conditions and processes due to interactions with these waters that changed the mineralogy. This procedure, called “diagenesis,” frequently removes the soil or makes complexs previous history and writes a brand-new one.
Diagenesis develops an underground environment that can support microbial life. In truth, some very special environments in the world– in which microbes prosper– are known as “deep biospheres.”
” These are outstanding locations to try to find evidence of ancient life and gauge habitability,” said John Grotzinger, CheMin co-investigator and co-author at the California Institute of Technology, or Caltech, in Pasadena, California. “Even though diagenesis may eliminate the signs of life in the initial lake, it creates the chemical gradients required to support subsurface life, so we are truly delighted to have actually discovered this.”
The Mast Camera (Mastcam) on NASAs Curiosity Mars rover caught this mosaic as it checked out the “clay-bearing unit” on Feb. 3, 2019 (Sol 2309). This landscape consists of the rocky landmark nicknamed “Knockfarril Hill” (center right) and the edge of Vera Rubin Ridge, which runs along the top of the scene. Credit: NASA/JPL-Caltech/MSSS
Researchers believe these outcomes provide further evidence of the effects of Mars climate change billions of years earlier. This info likewise will be utilized by NASAs Mars 2020 Perseverance rover team as they examine and pick rock samples for eventual return to Earth.
” Weve discovered something really essential: There are some parts of the Martian rock record that arent so proficient at protecting proof of the worlds past and possible life,” said Ashwin Vasavada, Curiosity project researcher and co-author at NASAs Jet Propulsion Laboratory in Southern California. “The fortunate thing is we find both close together in Gale Crater, and can use mineralogy to inform which is which.”
Curiosity remains in the preliminary phase of examining the shift to a “sulfate-bearing unit,” or rocks believed to have formed while Mars climate dried.
Reference: “Brine-driven damage of clay minerals in Gale crater, Mars” by T. F. Bristow, J. P. Grotzinger, E. B. Rampe, J. Cuadros, S. J. Chipera, G. W. Downs, C. M. Fedo, J. Frydenvang, A. C. McAdam, R. V. Morris, C. N. Achilles, D. F. Blake, N. Castle, P. Craig, D. J. Des Marais, R. T. Downs, R. M. Hazen, D. W. Ming, S. M. Morrison, M. T. Thorpe, A. H. Treiman, V. Tu, D. T. Vaniman, A. S. Yen, R. Gellert, P. R. Mahaffy, R. C. Wiens, A. B. Bryk, K. A. Bennett, V. K. Fox, R. E. Millken, A. A. Fraeman and A. R. Vasavada, 9 July 2021, Science.DOI: 10.1126/ science.abg5449.
The mission is managed by JPL, a department of Caltech, for NASAs Science Mission Directorate, Washington. Coworkers in NASAs Astromaterials Research and Exploration Science Division at Johnson and NASAs Goddard Space Flight Center in Greenbelt, Maryland, likewise are authors on the paper, as well as other institutions dealing with Curiosity.

A self-portrait of NASAs Curiosity rover handled Sol 2082 (June 15, 2018). A Martian dust storm has reduced sunshine and presence at the rovers place in Gale Crater. Credit: NASA/JPL-Caltech/MSSS
A brand-new paper enriches researchers understanding of where the rock record destroyed or preserved evidence of Mars previous and possible signs of ancient life.
Today, Mars is a world of extremes– its ice-cold, has high radiation, and is bone-dry. But billions of years earlier, Mars was house to lake systems that might have sustained microbial life. As the planets climate altered, one such lake– in Mars Gale Crater– gradually dried out. Researchers have brand-new proof that supersalty water, or brines, seeped deep through the cracks, between grains of soil in the dry lake bottom and altered the clay mineral-rich layers underneath.
The findings released in the July 9 edition of the journal Science and led by the group in charge of the Chemistry and Mineralogy, or CheMin, instrument– aboard NASAs Mars Science Laboratory Curiosity rover– aid include to the understanding of where the rock record destroyed or protected evidence of Mars possible and past indications of ancient life.

Billions of years back, Mars was house to lake systems that might have sustained microbial life. As the worlds environment changed, one such lake– in Mars Gale Crater– slowly dried out. Instead, they discovered mudstones abundant with iron oxides– minerals that offer Mars its characteristic rusty red color.
The Mast Camera (Mastcam) on NASAs Curiosity Mars rover caught this mosaic as it checked out the “clay-bearing system” on Feb. 3, 2019 (Sol 2309). Researchers think these results offer more evidence of the effects of Mars climate change billions of years ago.