MessageToEagle.com - Thousands of unusual gray spherules, made of iron and rock were the most important discovery made by the Mars Exploration Rover Opportunity as soon as it set down on Meridiani in January 2004.

A NASA news release of March 18, 2004 referred to these spherical iron-oxide concretions - as "blueberries".

Thousands of them were found embedded in and surrounding rocks near the landing site of the robot Opportunity rover on Mars.

"Blueberries", a few millimeters in diameter, formed within the soft sandstones of Meridiani Planum (rich in the iron mineral hematite deposits, according to Mars Global Surveyor data) when they were soaked with groundwater.

How were these unusual Martian spherules created? Thousands of unusual gray spherules, made of iron and rock but dubbed blueberries, were found embedded in and surrounding rocks near the landing site of the robot Opportunity rover on Mars. To help investigate their origin, Opportunity found a surface dubbed the Berry Bowl with an indentation that was rich in the Martian orbs.
The Berry Bowl is pictured above, imaged during rover's 48th Sol on Mars. The average diameter of a blueberry is only about 4 millimeters. By analyzing a circular patch in the rock surface to the left of the densest patch of spherules, Opportunity obtained data showing that the underlying rock has a much different composition than the hematite rich blueberries. This information contributes to the growing consensus is that these small, strange, gray orbs were slowly deposited from a bath of dirty water. Mars Exploration Rover Mission, JPL, NASA

Nasa scientists, highly intrigued by these objects, had many unsolved questions: "What is the distribution of these things within the soil?" How were these unusual Martian spherules created?

"Are we going to see granules below the surface or are they just distributed across the top? Are we going to see a dense concentration of granules all the way down?"

"Where did these spherules that are embedded in the outcrop come from?". "Did they grow in place? What is the composition of the outcrop? What does it tell us about the possibility that water is involved?"

Now, two scientists David Wacey and Matt Kilburn of the University of Western Australia discovered that microbes helped shape rare spheres of iron-oxide on Earth may aid the newly landed Curiosity Rover in its search for the first verifiable signs of extra-terrestrial life in similar rocks on Mars.

Previous theories suggested these concretions were formed by simple chemical reactions without the help of life. However, new UWA research shows clear evidence that microbes were essential in their formation.

This raises the possibility that Martian "blueberries" may not only reveal that water was present on Mars - but also life too.

Click on image to enlarge

Big spherules near Victoria

Spherules up to about 5 millimeters (one-fifth of an inch) in diameter. The camera took this image during the 924th Martian day, or sol, of Opportunity's Mars-surface mission (Aug. 30, 2006), when the rover was about 200 meters (650 feet) north of Victoria Crater.
Opportunity discovered spherules like these, nicknamed "blueberries," at its landing site in "Eagle Crater," and investigations determined them to be iron-rich concretions that formed inside deposits soaked with groundwater. However, such concretions were much smaller or absent at the ground surface along much of the rover's trek of more than 5 kilometers (3 miles) southward to Victoria. The big ones showed up again when Opportunity got to the ring, or annulus, of material excavated and thrown outward by the impact that created Victoria Crater. Image credit: NASA/JPL-Caltech/Cornell/U.S. Geological Survey

Wacey and Kilburn used high-resolution NanoSIMS technology at the University's Centre for Microscopy, Characterisation and Analysis to show clear relationships in the Utah concretions between microbe-like forms and concentrations of biological elements such as carbon and nitrogen.

Earth-based analogues for these "blueberries" are found in the Jurassic Navajo Sandstone near the Colorado River, Utah, where the concretions range in size from small marbles to cannonballs and consist of a hard shell of iron oxide surrounding a softer sandy interior.

Click on image to enlarge

Martian spherules, commonly called blueberries, discovered by Opportunity

Researchers hypothesize that some layer beneath the surface in Victoria's vicinity was once soaked with water long enough to form the concretions, that the crater-forming impact dispersed some material from that layer, and that Opportunity might encounter that layer in place if the rover drives down into the crater. Credits: NASA

University of Nebraska Assistant Professor Karrie Weber said UWA's CMCA facility - which is used to study everything from early life on Earth to cancer drugs, plant biology, rocks and soils, and nanotechnology - was chosen because of its demonstrated success in identifying microbial fossils.

The latest six-wheeled Mars Rover - Curiosity - landed successfully on August 6 after a 570 million kilometre journey from Earth. The touch-down site at Gale Crater was chosen for its geological potential to reveal signs of water and past microbial life.

Dr Wacey said scientists hoped Curiosity Rover would find more "Martian blueberries" near the new landing site. Should this occur, the robot is equipped to identify mineralogy, detect organic material, capture high-resolution images and bring humans a step closer to answering the question "are we alone?"

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