During the same relative time period, other clues indicate more oxygen was present in the atmosphere thanfound currently
Space news (planetary science: Martian rocks containing manganese oxide minerals; indicating a wetter surface with more atmospheric oxygen than presently found on Mars) – Mars (the Red Planet), 154 million miles (249 kilometers) from Sol, or 141 million miles (228 million kilometers) from Earth, on average –
NASA’s Curiosity Mars rover has found rocks at a place called Windjana containing manganese oxide minerals according to reports from planetary scientists studying samples from the region. On Earth rocks of this type formed during the distant past in the presence of abundant water and atmospheric oxygen. This news added to previous reports of ancient lakes and other groundwater sources during Mar’s pastpoints to a wetter environment in the study region Gale Crater during this time.
Planetary scientists used the laser-firing instrument on the Curiosity Mars rover to detect high levels of manganese-oxide in mineral veins found at Windjana. “The only ways on Earth that we know how to make these manganese materials involve atmospheric oxygen or microbes,” said Nina Lanza, a planetary scientist at Los Alamos National Laboratory in New Mexico. “Now we’re seeing manganese oxides on Mars, and we’re wondering how the heck these could have formed?”
Planetary scientists are looking at other processes that could create the manganese-oxide they found in rocks in Mar’s Gale Crater region. Possible culprits at this point include microbes, but even optimistic planetary scientists are finding little fan fair accompanyingtheir ideas. Lanza said, “These high manganese materials can’t form without lots of liquid water and strongly oxidizing conditions. Here on Earth, we had lots of water but no widespread deposits of manganese oxides until after the oxygen levels in our atmosphere rose.”
Geologists have found high concentrations of manganese oxide minerals is an important marker of a major shift in Earth’s atmospheric composition, from relatively low oxygen levels during the distant past, to the oxygen-rich environment we live in today. Planetary scientists studying the rocks they found in Gale Crater suggest the presence of these materials indicates oxygen levels on Mars rose also, before declining to the present low levels detected. The question is how was Mar’s oxygen-rich atmosphere formed?
“One potential way that oxygen could have gotten into the Martian atmosphere is from the breakdown of water when Mars was losing its magnetic field,” said Lanza. “It’s thought that at this time in Mars’ history, water was much more abundant. Yet without a protective magnetic field to shield the surface, ionizing radiation started splitting water molecules into hydrogen and oxygen. Because of Mars’ relatively low gravity, the planet wasn’t able to hold onto the very light hydrogen atoms, but the heavier oxygen atoms remained behind. Much of this oxygen went into rocks, leading to the rusty red dust that covers the surface today. While Mars’ famous red iron oxides require only a mildly oxidizing environment to form, manganese oxides require a strongly oxidizing environment, more so than previously known for Mars.“
Lanza added, “It’s hard to confirm whether this scenario for Martian atmospheric oxygen actually occurred. But it’s important to note that this idea represents a departure in our understanding for how planetary atmospheres might become oxygenated. Abundant atmospheric oxygen has been treated as a so-called biosignature or a sign of extant life, but this process does not require life.“
The Curiosity rover has been investigating Gale Crater for around four years and recent evidence supports the possibilityconditions needed to form these deposits were present in other locations. The concentrations of manganese oxide discovered were found in mineral-filled cracks in sandstones in a region of the crater called “Kimberley”. NASA’s Opportunity rover has been exploring the surface of the planet since 2004 and recently reported similar high manganese deposits in a region thousands of miles away. Supporting the idea environments required to form similar deposits could be found well beyond Gale Crater.
What’s next for Curiosity?
NASA’s Curiosity rover’s currently collecting drilled rock powder from the 14th drill site called the Murray formation on the lower part of Mount Sharp. Plans call for NASA’s mobile laboratory to head uphill towards new destinations as part of a two-year mission extension starting near the beginning of October.
The rover will go forward about a-mile-and-a-half (two-and-a-half-kilometers) to a ridge capped with material rich in the iron-oxide mineral hematite first identified by observations made with NASA’s Mars Reconnaissance Orbiter. Just beyond this area, there’s also a region with clay-rich bedrock planetary scientists want to have a closer look.
NASA has been exploring these key exploration sites on lower Mount Sharp as part of an effort to investigate evidence the Red planet was once a much wetter environment, which contrasts with the pictures of Mars we have received from our orbiters and rovers. A wetter environment where life could have taken root and grown.
“We continue to reach higher and younger layers on Mount Sharp,” said Curiosity Project Scientist Ashwin Vasavada, of NASA’s Jet Propulsion Laboratory, Pasadena, California. “Even after four years of exploring near and on the mountain, it still has the potential to completely surprise us.”
Planetary scientists found the Murray formation consists primarily of mudstone, which on Earth would form from mud accumulated on the bottom on an ancient lake. This seems to indicate any lake environment that existed on the Red Planet lasted awhile, but we’ll need to investigate this possibility more. Plans are for Curiosity to investigate the upper regions of the Murray formation, ahead, for at least one year of the mission.
“We will see whether that record of lakes continues further,”Vasavada said. “The more vertical thickness we see, the longer the lakes were present, and the longer habitable conditions existed here. Did the ancient environment change over time? Will the type of evidence we’ve found so far transition to something else?”
Vasavada said, “The Hematite and the Clay units likely indicate different environments from the conditions recorded in the older rock beneath them and different from each other. It will be interesting to see whether either or both were habitable environments.”
NASA’s Curiosity Mars Rover could be traversing terrain similar to large grained sandstone deposits found on Earth scientists studying images taken of the region surrounding the spacecraft believe.
The 160 degree landscape panorama below photographed by Curiosity’s Navigation Camera (Navcam) on February 19, 2014 during a stop on the missions 574th day shows an eroded sandstone outcrop called Junda and Mount Sharp on the horizon. The panoramic image below is centered on “the Kimberley”, a region 282 feet south from the rovers location, NASA scientists are heading Curiosity toward.
The 360-degree panorama below is also centered on the Kimberley region to the south. The outcrop of eroded sandstone in the foreground is the same one seen in the 160 degree panorama above.
The Kimberley region and Mount Sharp were chosen as prime targets of interest for NASA’s Curiosity Mars Rover due to study of images taken from orbit of the region last year. Planetary scientists want to take a look at the Kimberley region because four types of sandstone with different textures intersect there.
“The orbital images didn’t tell us what those rocks are, but now that Curiosity is getting closer, we’re seeing a preview,” said Curiosity Deputy Project Scientist Ashwin Vasavada of NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “
The contrasting textures and durabilities of sandstones in this area are fascinating. While superficially similar, the rocks likely formed and evolved quite differently from each other.”
The resistance to erosion of different rock types in a location 400 meters north-northwest of the Kimberley results in the different elevations and surfaces shades seen here. Higher elevations indicates more erosion resistant rock, while the flat, tanned surface is a sandstone with low resistance to erosion. This means the medium height rocks to the right center are less resistant to erosion than the taller rocks at the top of the image.
In earth geology sand is defined as fragmentary sediment smaller than 2 mm and 0.062 mm in diameter. Sandstone is the second most abundant sedimentary rock (20-25%) on Earth. The environment of deposition of surface rocks is generally related to mineral composition. A study of erosion of surface rocks and their mineral composition could provide planetary scientists with clues concerning the environment sandstone was formed in millions of years ago.
In geology the material between grains of sand in sandstone is called cement, whatever it’s composition. On earth the particular characteristics of cement varies quite a bit, depending on the environmental and geophysical history of the sandstone formation studied. Sandstones with a high percentage of clay-minerals are generally soft and will readily crumble when hit with a hammer. Sandstone with quartz cement is usually hard and rings when struck with a hammer.
Planetary scientists are hoping to have time in the planned schedule of Curiosity to study the sandstone in the Kimberly region. The results would be very interesting and could tell us a lot about the geological history of the Red Planet.
For the most part, the surface terrain NASA’s Curiosity Mars Rover has travelled over thus far was finer grained mud stone, rather than the coarser-grained sandstone outcroppings they expect to discover once they reach the Kimberley region of Mars. Sandstone has been seen in a number of different forms on planet Earth and some earth scientists were probably expecting forms to exist on other planets. Time permitting, planetary scientists are hoping to grab a sample of the terrain in the Kimberley region, they can study in depth using laboratory instruments inside Curiosity.
As with earth geology, an understanding of the process that created the different sandstone formations and outcrops in the Kimberly region, could help explain terrain found in Mars Gale Crater and the reason it has a large layered mountain, Mount Sharp, near its center.
“A major issue for us now is to understand why some rocks resist erosion more than other rocks, especially when they are so close to each other and are both likely to be sandstones,” said Michael Malin of Malin Space Science Systems, San Diego.
Astronomy News – The human journey to the beginning of space and time reached another milestone today as NASA’s Curiosity spacecraft fired its infrared laser for the 100,000th time. Curiosity has been conducting an experiment to determine the basic chemical elements contained within martian rocks and soils using the Chemistry and Camera Instrument (ChemCam). ChemCam has fired more than 102,000 times as of December 01, 2013, at 420 martian rocks and soils, and taken over 1,600 HD pictures using its onboard camera.
At the moment, an international team of astronomers and scientists are going over the data provided by Curiosity and ChemCam in order to list the chemical elements contained within the 420 samples they fired the laser at. This will give them a good idea of the chemical elements on the surface of Mars’ Gale Crater and the geophysical processes that formed them. ChemCam fires an infrared laser at rocks and soil targets to create plasma gas, which it analysis using a scientific technique called laser-induced breakdown spectroscopy.
Curiosity is the first NASA mission to use this scientific technique to analysis rocks and soils on a different planet, but certainly not the last. You can learn more about ChemCam at http://www.msl-chemcam.com.