Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mars Express evidence for large aquifers on early Mars

01.12.2005


Substantial quantities of liquid water must have been stably present in the early history of Mars. The findings of OMEGA, on board ESA’s Mars Express, have implications on the climatic history of the planet and the question of its ’habitability’ at some point in its history.



These conclusions were drawn thanks to data on Martian surface minerals obtained by OMEGA (Observatoire pour la Mineralogy, l’Eau, les Glaces et l’Activité), the visible and infrared mapping spectrometer on board ESA’s Mars Express.

From previous observations, Mars must have undergone water-driven processes, which left their signature in surface structures such as channel systems and signs of extensive aqueous erosion. However, such observations do not necessarily imply the stable presence of liquid water on the surface over extended periods of time during the Martian history.


The data collected by OMEGA unambiguously reveal the presence of specific surface minerals which imply the long-term presence of large amounts of liquid water on the planet.

These ’hydrated’ minerals, so called because they contain water in their crystalline structure, provide a clear ’mineralogical’ record of water-related processes on Mars.

During 18 months of observations OMEGA has mapped almost the entire surface of the planet, generally at a resolution between one and five kilometres, with some areas at sub-kilometre resolution.

The instrument detected the presence of two different classes of hydrated minerals, ’phyllosilicates’ and ’hydrated sulphates’, over isolated but large areas on the surface.

Both minerals are the result of a chemical alteration of rocks. However, their formation processes are very different and point to periods of different environmental conditions in the history of the planet.

Phyllosilicates, so-called because of their characteristic structure in thin layers (’phyllo’ = thin layer), are the alteration products of igneous minerals (minerals of magmatic origin) sustaining a long-term contact with water. An example of phyllosilicate is clay.

Phyllosilicates were detected by OMEGA mainly in the Arabia Terra, Terra Meridiani, Syrtis Major, Nili Fossae and Mawrth Vallis regions, in the form of dark deposits or eroded outcrops.

Hydrated sulphates, the second major class of hydrated minerals detected by OMEGA, are also minerals of aqueous origin. Unlike phyllosilicates, which form by an alteration of igneous rocks, hydrated sulphates are formed as deposits from salted water; most sulphates need an acid water environment to form. They were spotted in layered deposits in Valles Marineris, extended exposed deposits in Terra Meridiani, and within dark dunes in the northern polar cap.

When did the chemical alteration of the surface that led to the formation of hydrated minerals occur? At what point of Mars’s history was water standing in large quantities on the surface? OMEGA’s scientists combined their data with those from other instruments and suggest a likely scenario of what may have happened.

"The clay-rich, phyllosilicate deposits we have detected were formed by alteration of surface materials in the very earliest times of Mars," says Jean-Pierre Bibring, OMEGA Principal Investigator.

"The altered material must have been buried by subsequent lava flows we observe around the spotted areas. Then, the material would have been exposed by erosion in specific locations or excavated from an altered crust by meteoritic impacts," Bibring adds.

Analysis of the surrounding geological context, combined with the existing crater counting techniques to calculate the relative age of surface features on Mars, places the formation of phyllosilicates in the early Noachian era, during the intense cratering period. The Noachian era, lasting from the planet’s birth to about 3.8 thousand million years ago, is the first and most ancient of the three geological eras on Mars.

"An early active hydrological system must have been present on Mars to account for the large amount of clays, or phyllosilicates in general, that OMEGA has observed," says Bibring.

The long-term contact with liquid water that led to the phyllosilicate formation could have existed and be stable at the surface of Mars, if the climate was warm enough. Alternatively, the whole formation process could have occurred through the action of water in a warm, thin crust.

OMEGA data also show that the sulphate deposits are distinct from, and have been formed after, the phyllosilicate ones. To form, sulphates do not need a particularly long-term presence of liquid water, but water must be there and it must be acidic.

The detection and mapping of these two different kinds of hydrated minerals point to two major climatic episodes in the history of Mars: an early – Noachian – moist environment in which phyllosilicates formed, followed by a more acid environment in which the sulphates formed. These two episodes were separated by a Mars global climatic change.

"If we look at today’s evidence, the era in which Mars could have been habitable and sustained life would be the early Noachian, traced by the phyllosilicates, rather than the sulphates. The clay minerals we have mapped could still retain traces of a possible biochemical development on Mars," Bibring concludes.

Franco Bonacina | alfa
Further information:
http://www.esa.int/SPECIALS/Results_from_Mars_Express_and_Huygens/SEMA1UULWFE_0.html

More articles from Physics and Astronomy:

nachricht A 100-year-old physics problem has been solved at EPFL
23.06.2017 | Ecole Polytechnique Fédérale de Lausanne

nachricht Quantum thermometer or optical refrigerator?
23.06.2017 | National Institute of Standards and Technology (NIST)

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: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Quantum thermometer or optical refrigerator?

23.06.2017 | Physics and Astronomy

A 100-year-old physics problem has been solved at EPFL

23.06.2017 | Physics and Astronomy

Equipping form with function

23.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>