IR spectroscopy of hydrated planetary materials – SPRING

In order to understand the origin of Martian carbonates, we have designed an environmental cell that enables to measure the kinetics of carbonate synthesis in situ (by gas-solid reaction). In order to understand the hydrous mineralogy of carbonaceous chondrites, our analytical approach is triple : i) infrared spectrocopy of powder diluted in KBr ii) thermogravimetric analysis (TGA) iii) synchrotron Fe-XANES spectroscopy
In order to construct a link with hydrated asteroid, we perform reflectance spectra measurements using the spectro-photo-goniometer available at IPAG . We also performed photometric measurements in collaboration with the University of Bern.

We have so far obtained a number of significant results that have been published in international peer review journal. First, we have constrained the NIR signature of HED meteorite which are connected to the asteroid 4-vesta (Beck et al., Icarus, 2011). In addition, we have measured the photometry of a 8 different meteorites (Beck et al., Icarus, 2012). We also studied the Fe-XANES spectra of the matrix of 7 different carbonaceous chondrites and revealed the presence of an oxidation trend (Beck et al., GCA, 2012). The amount of water contained in carbonaceous chondrites has been determined by TGA analysis, and these results were presented at the Goldschmitt conference and have been submitted. Finally, our study of the 3-µm band of Mars has enabled to help in interpreting the dielectric map of the Martian surface (Mouginot et al., 2012).

Two majors perpectives have been opened already. The first is the systematic characterization of meteorite by combining TGA and infrared spectroscopy. In the future we will try to develop a laboratory calibration that will enable to quantify water on asteroids from ground-based observations.
The second is the characterization of spectro-photometric effects on natural samples. This perspective will be followed by a study on synthetic sample, and we will try to quantify their impact on observation of small bodies.

Beck, P., Barrat, J. A., Grisolle, F., Quirico, E., Schmitt, B., Moynier, F., Gillet, P., Beck, C., 2011. NIR spectral trends of HED meteorites: Can we discriminate between the magmatic evolution, mechanical mixing and observation geometry effects? Icarus. 216, 560-571.
Beck, P., DeAndrade, V., Orthous-Daunay, F.-R., Veronesi, G., Cotte, M., Quirico, E., Schmitt, B., 2012. The redox state of iron in the matrix of CI, CM and metamorphosed CM chondrites by XANES spectroscopy. Geochimica et Cosmochimica Acta.
Beck, P., Pommerol, A., Thomas, N., Schmitt, B., Moynier, F., 2012. Photometry of meteorites. Icarus. 218, 364-377.
Garenne, A., Montes-hernadez, G., Beck, P., Schmitt, B., Brissaud, O., Submitted. Gas-solid carbonation as a source of carbonates on Mars. . Planetary and space sciences.
Mouginot, J., Pommerol, A., Beck, P., Kofman, W., Clifford, S. M., 2012. Dielectric map of the Martian northern hemisphere and the nature of plain filling materials. Geophysical Research Letters. 39.

Because water is the most important molecule in the origin and sustainability of life, the “follow the water” motto has been guiding space agencies over the last decades in their Solar System exploration programs. Here, we will study water related alteration processes that have occurred at the surface of Mars and Asteroids.

For solar system objects, three types of surface observations are available to the scientific community i) global to regional by mean of orbiting spacecraft observations ii) global using Earth-based observations with large telescope iii) “ground truth” as seen by landers in a few discrete locations. Unfortunately, the number of techniques that can be applied remotely or shipped through the Solar System is limited and laboratory measurements are always needed to interpret these observations.

For both Mars and asteroids, most surface material identifications have been based on infrared spectroscopy. This method is one of the few techniques that can directly probe protons, and is thus well suited for the identification of –OH and H2O bearing mineral phases. In this project, we propose to perform laboratory measurements and develop original experiments that will enable to determine the nature of surface hydrated materials observed on Mars and asteroids.

First, we will perform a basic effort on the understanding of the crystallographic processes controlling the water and hydroxyl IR absorption within mineral phases. This effort will enable to understand the role of the bonding cation and the effect of crystallinity and crystal structure on the NIR spectra. Reference material will be collected and measured in reflectance mode with the unique spectro-photo-goniometer available at LPG, and under dry conditions within the SERAC chamber.

In addition, we will study current weathering processes on Mars in the laboratory. We will first try to constrain the crystallographic products of surface weathering by trying to reproduce a typical IR spectrum of the Martian surface. We will also investigate the potential impact of gaseous CO2/silicate reactions that might produce carbonates, and explain recent observations on Mars.

Finally, the IR spectra of carbonaceous chondrites will be measured in reflectance mode within an environmental cell, to provide a valid comparison with low albedo asteroids. This will enable to interpret the 3-µm spectral feature and possibly to constrain the intensity of aqueous alteration experienced by asteroids. These data will be of great interest in the context of the ROSETTA and DAWN mission.

This project will build collaboration between two young but already experienced scientists, Pierre Beck and German Montes-Hernandez. They belong to two different laboratories located in Grenoble, which possess synergetic competence. The SPRING project will forge a strong connection between the two researchers, and help them in creating a new and active research group.
This study is very ambitious since it requires the dual knowledge of material science and planetary observations. The PI of this project Pierre Beck is young (29) and was hired two years ago at LPG. It is the third year he is submitting a project to the ANR and the SPRING project is the result of 2 years of scientific maturation. The scientific goals of this project are fundamental and ambitious, but certainly achievable.
Most of the project funding will concern the hiring of a PhD candidate that will be trained by P. Beck and G. Montes-Hernandez. G. Montes-Hernandez has an HDR and P. Beck plan to defend this diploma by the end of the SPRING project. In addition, a significant part of funding will involve analytical development, for which the LPG has a worldwide recognized experience.