Carbonates Found On Mars Adds To Mystery

Researchers using a powerful instrument aboard NASA's Mars Reconnaissance Orbiter have found a long sought-after mineral on the Martian surface and, with it, unexpected clues to the Red Planet's watery past.

Surveying intact bedrock layers with the Compact Reconnaissance Imaging Spectrometer for Mars, or CRISM, scientists found carbonate minerals, indicating that Mars had neutral to alkaline water when the minerals formed at these locations more than 3.6 billion years ago. Carbonates, which on Earth include limestone and chalk, dissolve quickly in acid. Therefore, their survival until today on Mars challenges suggestions that an exclusively acidic environment later dominated the planet. Instead, it indicates that different types of watery environments existed. The greater the variety of wet environments, the greater the chances one or more of them may have supported life.

"We're excited to have finally found carbonate minerals because they provide more detail about conditions during specific periods of Mars' history," said Scott Murchie, principal investigator for the instrument at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md.

The findings will appear in the Dec. 19 issue of Science magazine and were announced Thursday at a briefing at the American Geophysical Union's Fall Meeting in San Francisco.

New research discounts Mars ocean evidence
by Jeff Foust
April 7 2001
SpaceFlightNow
In a paper published in Thursday's issue of the journal Nature, planetary scientists at the University of Arizona and MIT said that features in images of the planet previously thought to be remains of ancient shorelines are more likely linked to the planet's volcanoes. Paul Withers of the University of Arizona and Gregory Neumann of MIT decided to reexamine the MOLA data for some of the paleoshoreline features identified in the earlier work. They found, though, a closer correlation between the features and tectonic activity than any processes related to the formation of shorelines. According to Withers, the key piece of evidence was the terraces identified in the earlier study. Instead, those features are more likely tectonic stress ridges created by massive volcanism earlier in the planet's history.
NASA Finds Red Planet Is Rich In Green Gem
Telegraph (UK)
10-24-2003
Large outcrops of a gemstone mineral commonly used in jewellery have been found on Mars, scientists said yesterday. On Earth the mineral, olivine, takes the form of the brilliant green gemstone peridot. An instrument aboard a Nasa spacecraft spotted an area of nearly 19,000 square miles rich in olivine in the Nili Fossae region of Mars. It is thought that the broken nature of the ground at Nili Fossae may be linked to the Isidis impact basin, formed long ago by an asteroid or comet. On Earth, exposed olivine weathers and breaks down quickly because of the planet's relatively warm, wet weather. If the mineral has been there since early in the planet's history, it would mean the planet has been cold and dry for most of its life.
NASA Gets A Good Look At Mars Soil And A True Puzzle
by Jeremy Manier
1/07/2004
It's difficult to imagine life surviving now in the barren landscape around the rover--though mission planners have said one goal of the robotic Mars expeditions is to scout out possible landing sites in case the U.S. ever sends astronauts to Mars...The sticky-looking soil may be the first true puzzle of the mission, scientists said. Technicians believe the probe's landing airbags disturbed the dirt near the rover when they retracted back under the craft, soon after the landing. The dirt that was dragged by the airbags now looks oddly folded, almost as if it were damp clay... Researchers believe Martian soil in the rover's vicinity is bone-dry near the surface, adding to the mystery. Squyres said it's possible that moisture evaporating from below left a salty, cohesive crust at the surface.
Red planet's hue due to meteors, not water
by Hazel Muir
12/21/2006
"There is something of a paradox about Mars," agrees Joshua Bandfield of Arizona State University in Tempe. His team recently showed that the planet has no large deposits of carbonates, which should have formed if giant pools of water had persisted on the surface. Bandfield suggests that liquid water must have occasionally burst out of the ground, carving channels and gullies, but that it quickly froze again in the frigid Martian climate.
New Data Suggest Mars Soil Not As Life-Friendly As Thought
by Andrea Thompson
8/04/2008
Two samples analyzed within the last month by Phoenix's Microscopy, Electrochemistry and Conductivity Analyzer (MECA) suggest that the Martian dirt may contain perchlorate, a highly oxidizing substance, which would create a harsh environment for any potential life. The findings stand against the results from MECA's first analysis, which indicated the dirt was Earth-like in certain respects, including its pH and the presence of certain minerals. "Initial MECA analyses suggested Earth-like soil. Further analysis has revealed un-Earthlike aspects of the soil chemistry," said Phoenix principal investigator Peter Smith.
Mars 'remains in embryonic state'
by Jennifer Carpenter
5/27/2011
Mars formed in record time, growing to its present size in a mere three million years, much quicker than scientists previously thought. Its rapid formation could explain why the Red Planet is about one tenth the mass of Earth. The study supports a 20-year-old theory that Mars remained small because it avoided collisions with planetary building material... Scientists believe that the planets grew from material pulled together by electrostatic charges - the same force that's behind the "dust bunnies" under your bed. These proto-planetary dust balls grew and grew until they formed what scientists term "embryo" planets. These rocky masses were large enough to exert a considerable gravitational force on surrounding material, including other nascent planets.
Clay Deposits Don't Prove Existence of Ancient Martian Lakes
by Jason Major
September 10, 2012
A research team led by Alain Meunier of the Université de Poitiers in France studied lavas containing iron and magnesium -- similar to ancient clays identified on the surface of Mars -- in the French Polynesian atoll of Moruroa. The team's findings show that the same types of clay outcrops can be caused by the solidifying of water-rich magma in a volcanic environment, and don't require Earthlike aquatic conditions at all. The results also correlate to the deuterium-to-hydrogen (D/H) ratio within clays found in Martian meteorites... Additionally, the clay deposits found on Mars can be several hundred meters thick, which seems to be more indicative of upwelling magma than interactions with water.

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