Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Signs of acid fog found on Mars

03.11.2015

And spirit, the little rover that could

While Mars doesn't have much in the way of Earth-like weather, it does evidently share one kind of weird meteorology: acid fog.


This is a false-color mosaic of Cumberland Ridge, with superimposed pie charts representing iron-bearing mineralogy. You don't need to know anything about iron geochemistry to know that the stuff represented by the pie charts varies greatly across this scene, which is about 1/3 the size of a football field. Also, the 1.2 m scale bar is the distance between the rover's right and left wheel track. Image from S. Cole, PhD thesis; background image: NASA/JPL/Cornell/Arizona State University; Moessbauer values from Morris et al. 2008 (doi: 10.1029/2008JE003201).

Credit

Image from S. Cole, PhD thesis; background image: NASA/JPL/Cornell/Arizona State University; Moessbauer values from Morris et al. 2008 (doi: 10.1029/2008JE003201).

Planetary scientist Shoshanna Cole has pieced together a compelling story about how acidic vapors may have eaten at the rocks in a 100-acre area on Husband Hill in the Columbia Hills of Gusev Crater on Mars. She used a variety of data gathered by multiple instruments on the 2003 Mars Exploration Rover Spirit to tease out information from exposures of the ancient bedrock. She will be presenting her work on Monday, Nov. 2, in Baltimore, Maryland, at the annual meeting of the Geological Society of America.

The work focused on the 'Watchtower Class' outcrops on Cumberland Ridge and the Husband Hill summit, said Cole, who is an assistant professor at Ithaca College and began studying the area for her Ph.D. thesis at Cornell University.

... more about:
»Geological »Mars »acid »acids »eruptions »structure

"The special thing about Watchtower Class is that it's very widespread and we see it in different locations. As far as we can tell, it's part of the ground there," which means that these rocks record environments that existed on Mars billions of years ago.

By combining data from previous studies of the area on Mars, Cole saw some intriguing patterns emerge. Spirit examined Watchtower Class rocks at a dozen locations spanning about 200 meters along Cumberland Ridge and the Husband Hill summit. The chemical composition of these rocks, as determined by Spirit's Alpha Proton X-ray Spectrometer (APXS), is the same, but the rocks looked different to all of the other instruments.

Across Cumberland Ridge -- which is about 1/3 the size of a football field -- the Mössbauer Spectrometer showed there was a surprisingly wide range in the proportion of oxidized iron to total iron, as if something had reacted with the iron in these rocks to different degrees. This iron oxidation state ranges from 0.43 to 0.94 across a span of only 30 meters. Meanwhile, data from both the Mössbauer Spectrometer and the Miniature Thermal Emission Spectrometer (Mini-TES) showed that the minerals within the rocks changed and lost their structure, becoming less crystalline and more amorphous. And these trends match the size of small bumps, which Cole calls agglomerations, seen in Pancam and Microscopic Imager pictures of the rocks.

"So we can see the agglomerations progress in size from west to east and the iron changes in the same way," Cole said. "It was super cool."

But the fact that the rocks were otherwise the same in composition indicates that they were originally identical. "That makes us think that they were made of the same stuff when they started out. Then something happened to make them different from each other."

Cole hypothesizes that the rocks were exposed to acidic water vapor from volcanic eruptions, similar to the corrosive volcanic smog, or "vog," that poses health hazards in Hawaii from the eruptions of Kilauea. When the Martian vog landed on the surface of the rocks it dissolved some minerals, forming a gel. Then the water evaporated, leaving behind a cementing agent that resulted in the agglomerations.

"So nothing is being added or taken away, but it was changed," Cole said. "This would have happened in tiny amounts over a very long time. There's even one place where you see the cementing agent healing a fracture. It's pretty awesome. I was pretty happy when I found that one."

More support of this idea comes from a 2004 study in which scientists conducted laboratory experiments exposing mock martian basalt rocks (based on data from the Mars Pathfinder mini-rover) to sulfuric and hydrochloric acids. The results indicated that as these rocks are exposed to acids, they lose their crystalline structure -- just like what Cole sees in varying degrees across the Watchtower Class exposures.

As for why there is a trend in the iron and the degree to which the rocks were changed, the answer is microclimates, similar to those in different areas of your home garden. The time that the gel was present on the rocks depended on how much sunshine and wind the rocks got. The more altered rocks, which have larger agglomerations, are on very steep slopes facing away from the Sun, which makes them shadier. The least altered rocks are on sunnier and gentler slopes, according to Cole.

Piecing together this Martian vog puzzle underscores the story of Spirit's success.

"Spirit's the rover who always had to try harder," she said. "She was sent to Gusev Crater to look for lake deposits, but landed in lava field. She had to make a long trek to the Columbia Hills to find evidence of ancient watery environments. There's still tons of data to analyze there, and that's really nifty."

###

CONTACT:
Shoshanna Cole
607-274-5722
scole@ithaca.edu
Assistant Professor, Department of Physics and Astronomy, Ithaca College

WHAT:
Session 94
Mineralogy of Diagenesis on Earth and Mars: In Honor of Nicholas J. Tosca, 2015 MSA Awardee
Session link: https://gsa.confex.com/gsa/2015AM/webprogram/Session37867.html

Paper 94-10
In-situ Evidence for Alteration by Acid Fog on Husband Hill, Gusev Crater, Mars
Abstract link: https://gsa.confex.com/gsa/2015AM/webprogram/Paper266774.html

WHERE & WHEN:
Monday, Nov. 2, 2015: 8:00 AM-12:00 PM
Room 342 (Baltimore Convention Center)
Presentation Time: 10:40 AM

The Geological Society of America, founded in 1888, serves more than 27,000 members from academia, government, and industry in more than 100 countries. Through its meetings, publications, and programs, GSA enhances the professional growth of its members and promotes the geosciences in the service of humankind. GSA encourages cooperative research among earth, life, planetary, and social scientists, fosters public dialogue on geoscience issues, and supports all levels of earth science education.

Media Contact

Christa Stratton
cstratton@geosociety.org
303-357-1093

 @geosociety

http://www.geosociety.org 

Christa Stratton | EurekAlert!

Further reports about: Geological Mars acid acids eruptions structure

More articles from Physics and Astronomy:

nachricht Water without windows: Capturing water vapor inside an electron microscope
13.12.2017 | Okinawa Institute of Science and Technology (OIST) Graduate University

nachricht Columbia engineers create artificial graphene in a nanofabricated semiconductor structure
13.12.2017 | Columbia University School of Engineering and Applied Science

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

A whole-body approach to understanding chemosensory cells

13.12.2017 | Health and Medicine

Water without windows: Capturing water vapor inside an electron microscope

13.12.2017 | Physics and Astronomy

Cellular Self-Digestion Process Triggers Autoimmune Disease

13.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>