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 A tale of two pulsars' tails: Plumes offer geometry lessons to astronomers
18.01.2017 | Penn State

nachricht Studying fundamental particles in materials
17.01.2017 | Max-Planck-Institut für Struktur und Dynamik der Materie

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: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

A big nano boost for solar cells

18.01.2017 | Power and Electrical Engineering

Glass's off-kilter harmonies

18.01.2017 | Materials Sciences

Toward a 'smart' patch that automatically delivers insulin when needed

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>