Could Clays Found in Ancient Gale Crater Lake on Mars Once Have Harbored Life?

Since 2012, the Mars Science Laboratory Curiosity rover has been exploring Gale crater on Mars and investigating whether or not the Purple Planet ever had the environmental situations to help microbial life. Gale crater, which shaped about 3.7 billion years in the past, is probably going the positioning of an historical lake. Gale crater is 96 miles in diameter, however the mountain at its middle, Aeolis Mons, is 18,000 ft. excessive.

One of many devices onboard Curiosity is known as CheMin (Chemistry and Mineralogy). CheMin makes use of X-ray diffraction to research rock and soil samples collected by Curiosity and decide the sorts of minerals current within the samples.

A latest research of clay minerals recognized by Curiosity at Gale crater found one thing new in regards to the type of the phyllosilicates in a piece of the rock analyzed by CheMin. Phyllosilicates are a bunch of minerals with a layered construction that embody micas, chlorite and smectites (additionally referred to as swelling clays).

Phyllosilicates kind underneath varied situations and may usually be used as markers to retrace historical past in geochemical detective work. Glauconitic clays, primarily discovered on Earth in each marine and lacustrine environments, have been recognized on this research from particular sorts of dysfunction within the mineral construction. These problems embody stacking faults and layer rotation attributable to intergrown smectite and glauconite minerals that every have a definite construction and produce an uncommon sample after they develop collectively.

Completely different from many different sorts of phyllosilicates, these glauconitic clays are glorious indicators of calm lake situations. “They solely kind when lake sediments reside for 1000’s of years on the interface between oxidizing and lowering environments,” mentioned lead writer Elisabeth Losa-Adams of the Departamento de Geociencias Marinas, Universidade de Vigo, Lagoas-Marcosende, Vigo, Spain. 

The findings of this research assist clarify variations between clay minerals investigated by Curiosity alongside its trek by way of various kinds of rock in Gale crater. “Smectite clays are frequent on Mars and are noticed throughout a lot of the planet from orbital research, however glauconitic clays are extra uncommon,” mentioned co-author Janice Bishop of the SETI Institute.

 

Clay on Mars Graphic
Attainable sequence of formation of glauconitic clays within the Murray formation rocks of Gale crater.

Glauconitization has been present in a number of lake settings on Earth, together with saline lakes with elevated salt ranges shaped by way of evaporation and precipitation and in Precambrian lakes by way of inorganic processes earlier than life arose. Whereas the presence of glauconitic clays doesn’t imply that life was current on Mars, the impartial pH, reasonable temperature, and long-lasting calm waters might have offered an ideal area of interest for microbes to flourish in the event that they have been current at Gale crater.

This analysis was revealed in Nature June 28, 2021: Long-lasting habitable periods in Gale crater constrained by glauconitic clays. The complete paper is obtainable at https://rdcu.be/cnlxZ.

 

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