"The big surprise from these new results is how pervasive and long-lasting Mars' water was, and how diverse the wet environments were," says Scott Murchie, CRISM's principal investigator at the Johns Hopkins University Applied Physics Laboratory (APL), in Laurel, Md.
One study, published in the July 17 issue of Nature, shows that vast regions of the ancient highlands of Mars -- which cover about half the planet -- contain clay minerals, which can form only in the presence of water. Volcanic lavas buried the clay-rich regions during subsequent, drier periods of the planet's history, but impact craters later exposed them at thousands of locations across the planet.
The clay-like minerals, called phyllosilicates, preserve a record of the interaction of water with rocks dating back to what is called the Noachian period of Mars’ history, about 4.6 billion to 3.8 billion years ago. This period corresponds to the earliest years of the solar system, when Earth, the moon and Mars sustained a cosmic bombardment by comets and asteroids. Rocks of this age have largely been destroyed on Earth by plate tectonics; they are preserved on the moon, but were never exposed to liquid water. The phyllosilicate-containing rocks on Mars therefore preserve a unique record of liquid water environments -- possibly suitable for life -- in the early solar system.
“The minerals present in Mars' ancient crust show a variety of wet environments,” says John Mustard, a member of the CRISM team from Brown University in Providence, R.I., and lead author of the Nature study. “In most locations the rocks are lightly altered by liquid water, but in a few locations they have been so altered that a great deal of water must have flushed though the rocks and soil. This is really exciting because we're finding dozens of sites where future missions can land to understand if Mars was ever habitable and if so, to look for signs of past life."
A companion study, published in the June 2 issue of Nature Geosciences, finds that the wet conditions persisted for a long time. Thousands to millions of years after the clays were formed, a system of river channels eroded them out of the highlands and concentrated them in a delta where the river emptied into a crater lake slightly larger than California’s Lake Tahoe, about 25 miles (40 kilometers) in diameter. "The distribution of clays inside the ancient lakebed shows that standing water must have persisted for thousands of years," says Bethany Ehlmann, another member of the CRISM team from Brown and lead author of the study of the ancient lake within Jezero Crater. "Clays are wonderful at trapping and preserving organic matter, so if life ever existed in this region, there's a chance of its chemistry being preserved in the delta."
CRISM’s combination of high spatial and spectral resolutions—better than any previous imaging spectrometer sent to Mars—reveals variations in the types and composition of the phyllosilicate minerals. By combining data from CRISM and MRO’s Context Imager (CTX) and High Resolution Imaging Science Experiment (HiRISE), the team has identified three principal classes of water-related minerals dating to the early Noachian period: aluminum-phyllosilicates, hydrated silica or opal, and the more common and widespread iron/magnesium-phyllosilicates. The variations in the minerals suggest that different processes, or different types of watery environments, created them.
"Our whole team is turning our findings into a list of sites where future missions could land to look for organic chemistry and perhaps determine whether life ever existed on Mars,” says APL’s Murchie.
APL, which has built more than 150 spacecraft instruments over the past four decades, led the effort to build CRISM, and operates the instrument in coordination with an international team of researchers from universities, government and the private sector. The Jet Propulsion Laboratory of the California Institute of Technology, Pasadena, manages the Mars Reconnaissance Orbiter mission for NASA’s Science Mission Directorate. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft.
The Applied Physics Laboratory, a division of the Johns Hopkins University, meets critical national challenges through the innovative application of science and technology. For more information, visit http://www.jhuapl.edu. For more information on CRISM, visit http://crism.jhuapl.edu.
Tracing aromatic molecules in the early universe
23.03.2017 | University of California - Riverside
New study maps space dust in 3-D
23.03.2017 | DOE/Lawrence Berkeley National Laboratory
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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