• Part One
• Fields of Hematite - Opportunity Rover Landing Site
• Of Blue Berries and Snails - Odd Anomaly
• Water on Mars... In the Past
• What Happened to the Water on Mars? - the "Blueberries"
• Part Two
• A Peek into 'Alamogordo Creek' - June 15, 2006  (peek)
• Evidence of a Water-Soaked Past - March 03, 2004 (Evidence)
• Part Three
• More "Blueberries" & Earth Equivalents
• Another Possibility
• Study of Hematite Concretions
• Part Four
  
• The Blueberry Fields of Barsoom ~ Opportunity's Mission to Meridiani Planum
• Part Five
• Blueberry Fields Forever

Water on Mars... In the Past

Distributory Fan Near Holden Crater PIA04869
Image Credit:  NASA/JPL/Malin Space Science Systems

The thermal emission imaging system (THEMIS) on Odyssey is both an infrared camera and a visible camera. It has captured telltale signs of past water on Mars. In four locations on Mars, THEMIS has detected high levels of hematite, a mineral that on Earth forms most often in the presence of liquid water. Discoveries by THEMIS and its predecessor instrument TES (thermal emission spectrometer) on the Mars Global Surveyor orbiter) led the 2003 Mars Exploration Rover mission team to choose Meridiani Planum as a landing site for its hematite content.

Since landing, data from the Opportunity rover's science instruments, including the miniature thermal emission spectrometer (mini-TES) has confirmed THEMIS' results that the area was once covered in water.

"The morphology and thermal properties of the Meridiani Planum region indicate that the hematite-bearing area was deposited in a standing body of water that extended over 100,000 square kilometers (300 miles by 100 miles or about the size of Oklahoma), with smaller bodies of water in nearby crater basins," said Christensen.

THEMIS, along with Christensen's two other instruments at Mars (TES on Mars Global Surveyor and mini-TES on the rovers), has shown that liquid water could have been in a few areas within the equatorial region of Mars for thousands or tens of thousands of years. 

Source NASA: Mission Success: The Magic of Mars Odyssey

Courtesy NASA/JPL-Caltech

This microscopic image, taken at the outcrop region dubbed "Berry Bowl" near the Mars Exploration Rover Opportunity's landing site, shows the sphere-like grains or "blueberries" that fill Berry Bowl. 

The "triple berry" seen in the center of the microscopic image is intriguing to scientists because it reveals a clue about how the blueberries formed. Spheres formed from impacts or volcanoes do not tend to mold together like the spheres seen in the microscopic image. Spheres from impacts or craters are usually round or teardrop-shaped from flying in the air and freezing before hitting the ground. Any droplets of magma that combine with other droplets usually grow into a single mass in a spherical, dumbbell, or teardrop shape. In contrast, concretions could form this triple berry shape. Concretions are spherical mineral structures formed by groundwater percolating through porous rocks. On Earth, as concretions grow in close proximity to each other, their outer edges often intersect each other, giving an appearance like a triple soap bubble.

Mineral in Mars 'Berries' Adds to Water Story - March 18, 2004 - Courtesy NASA

A major ingredient in small mineral spheres analyzed by NASA's Mars Exploration Rover Opportunity furthers understanding of past water at Opportunity's landing site and points to a way of determining whether the vast plains surrounding the site also have a wet history.

The spherules, fancifully called blueberries although they are only the size of BBs and more gray than blue, lie embedded in outcrop rocks and scattered over some areas of soil inside the small crater where Opportunity has been working since it landed nearly two months ago.

Individual spherules are too small to analyze with the composition-reading tools on the rover. In the past week, those tools were used to examine a group of berries that had accumulated close together in a slight depression atop a rock called "Berry Bowl." The rover's Mössbauer spectrometer, which identifies iron-bearing minerals, found a big difference between the batch of spherules and a "berry-free" area of the underlying rock.

"This is the fingerprint of hematite, so we conclude that the major iron-bearing mineral in the berries is hematite," said Daniel Rodionov, a rover science team collaborator from the University of Mainz, Germany. On Earth, hematite with the crystalline grain size indicated in the spherules usually forms in a wet environment.

Scientists had previously deduced that the martian spherules are concretions that grew inside water-soaked deposits. Evidence such as interlocking spherules and random distribution within rocks weighs against alternate possibilities for their origin. Discovering hematite in the rocks strengthens this conclusion. It also adds information that the water in the rocks when the spherules were forming carried iron, said Dr. Andrew Knoll, a science team member from Harvard University, Cambridge, Mass.

"The question is whether this will be part of a still larger story," Knoll said at a press briefing today at NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spherules below the outcrop in the crater apparently weathered out of the outcrop, but Opportunity has also observed plentiful spherules and concentrations of hematite above the outcrop, perhaps weathered out of a higher layer of once-wet deposits. The surrounding plains bear exposed hematite identified from orbit in an area the size of Oklahoma -- the main reason this Meridiani Planum region of Mars was selected as Opportunity's landing site.

"Perhaps the whole floor of Meridiani Planum has a residual layer of blueberries," Knoll suggested. "If that's true, one might guess that a much larger volume of outcrop once existed and was stripped away by erosion through time."

Courtesy NASA/JPL-Caltech

"Meridiani Planum" Piles of Hematite Spheres or "Blue Berries" between the drifts. With this and the red hematite stained sand it is clear that Mars is rich in Iron just lying on the surface.

Courtesy NASA/JPL-Caltech

"Bylot" In this false-color image from Opportunity, a mixture of blueberries and the more irregular, lighter-colored spherules scientists have named "popcorn" lie atop a rock named Bylot in the Axel Heiberg outcrop at Endurance Crater. NASA / JPL / Cornell

NASA's Mars Exploration Rover Opportunity is examining a type of rougher-textured, lighter-colored round pebbles that appear to be related to the smoother, darker spherules nicknamed "blueberries." The rover has found blueberries, which are actually gray, to be plentiful in Mars' Meridiani Planum region.