Komatiites: From Earth's Geological Settings to Planetary and Astrobiological Contexts

Komatiites are fascinating volcanic rocks. They are among the most ancient lavas of the Earth following the 3.8 Ga pillow basalts at Isua and they represent some of the oldest ultramafic magmatic rocks preserved in the Earth's crust at 3.5 Ga. This fact, linked to their particular features (high magnesium content, high melting temperatures, low dynamic viscosities, etc.), has attracted the community of geoscientists since their discovery in the early sixties, who have tried to determine their origin and understand their meaning in the context of the terrestrial mantle evolution. In addition, it has been proposed that komatiites are not restricted to our planet, but they could be found in other extraterrestrial setting in our Solar System (particularly in Mars and Io). It is important to note that komatiites may be extremely significant in the study of the origins and evolution of Life on Earth. They not only preserve essential geochemical clues of the interaction between the pristine Earth rocks and atmosphere, but also may have been potential suitable sites for biological processes to develop. Thus, besides reviewing the main geodynamic, petrological and geochemical characteristics of komatiites, this paper also aims to widen their investigation beyond the classical geological prospect, calling attention to them as attracting rocks for research in planetology and astrobiology.Comment: 53 pages, submitted (Nov 22th, 2005) to Earth, Moon and Planets and accepted for publication on Jan 18th, 2007. The new version is the corrected paper after acceptance for publicatio

Fijación atmosférica del nitrógeno por las descargas eléctricas a lo largo de la historia de la Tierra

Tesis doctoral en Ciencias (Chimie de la Pollution atmoshérique et Physique de l'Environnement) de l'Université de Paris XII, France, 2002.Tesis doctoral en Ciencias (Química Analítica) de la Universidad Autónoma de México (UNAM), 2000.Ce travail a été effectué en France au Laboratoire Interuniversitaire de Systèmes Atmosphériques de l'Université de Paris XII Val-de-Marne et au Mexique au Laboratorio de Química de Plasmas y Estudios Planetarios de l'Institut de Sciences Nucléaires de l'Université Nationale Autonome de Mexico dans le cadre du programme de coopération France-Mexique ECOS-ANUIES-SEP-CONACYT M97U01, des projets de recherche CONACYT-UNAM F323-M9211, -400349-5-1843E et -32531-T, UNAM-BID 95-B3-A-DGP-0000-0184, UNAM-DGAPA IN102796 et IN119999, des programmes d'appui PAEP 108315 et 208326, et des programmes de bourses complémentaires nationales DGEP/SAP/PBN/869/99, DGEP/SAP/PBN/388/2000, DGEP/SPIAP/PBN/248/2001 et DGEP/SPIAP/PBN/475/2002.Peer reviewe

Experimental simulation of chemistry induced by hypervelocity impacts on icy moons surfaces: laser-induced shocks in ices

40th Lunar and Planetary Science Conference, (Lunar and Planetary Science XL), held March 23-27, 2009 in The Woodlands, Texas, id.2507We have conducted laboratory experiments to study the possible chemical production induced by meteoritic impact shocks on planetary ices. A pulsed Nd-YAG laser was used to reproduce the shock phenomena during hypervelocity impacts into the ice.Peer reviewe

Fixation atmosphérique de l'azote par les décharges électriques durant l'histoire de la Terre

PARIS12-CRETEIL BU Multidisc. (940282102) / SudocSudocFranceMexicoFRM

Chemical production by Pulse-Laser Irradiation on Ices: Simulation of impact shock-induced chemistry

Poster presented at: Bioastronomy 2007: Molecules, Microbes and Extraterrestrial Life (July 16-20, 2007, San Juan de Puerto Rico).Chemical changes and synthesis occurring on icy satellites are generally explained by the influence of UV photons and high-energy charged particles on ices. Nonetheless, impact process onto ices could be especially advantageous and efficient as a local or global endogenic energy source for driving interesting surface chemistry. Impacts can ensure that ices are eventually exposed, for a limited period of time, to aqueous melt in impact craters and ejecta, allowing impurities included in the ice to undergo hydrolysis and other reactions. Upon impact, the kinetic energy of the bolide is transferred to the ground liberating a great deal of stress energy which could initiate in situ a diverse series of chemical reactions in the fracture zone beneath the crater.In the present work, we report the experimental results of a new approach testing in laboratory the chemistry conducted by impacts into planetary ices. Mixtures of pure water ices containing impurities like CO2, Na2CO3, CH3OH and CH3OH / (NH4)2SO4 were irradiated at 77K by a pulsed Nd-YAG laser beam (1064 nm). GC-MS and FTIR analyses show that hydrogen peroxide, carbon monoxide and methanol are formed in irradiated H2O / CO2 ices. Ice containing sodium carbonate generates under laser radiation CO and CO2 which are also products of the irradiated H2O / CH3OH and H2O / CH3OH / (NH4)2SO4 ices. Besides, methane and more complex molecules are produced after irradiating ices containing methanol and, adding ammonium sulfate to the methanol induces the production of nitrogen compounds such as N2O, HCN and CH3CN.Peer reviewe

Quantitative study of methane-nitrogen mixed clathrates using gas chromatography and Raman spectroscopy for their detection in icy surfaces of the outer solar system

International audienc

New application of microwave digestion–inductively coupled plasma-mass spectrometry for multi-element analysis in komatiites

10 pages, 1 figure, 8 tables.-- Published online 11 September 2008.The original publication is available at http://www.sciencedirect.com/science/journal/00032670A new method using microwave digestion combined with inductively coupled plasma-mass spectrometry (ICP-MS) was studied to analyze the elemental composition of a variety of komatiites samples. Microwave digestion consisted in two-stage heating and pressurizing acid treatments for maximum dissolution of the samples. We report here different quality control measurements (external and internal calibration, monitoring of reference materials) which involve standard deviation calculations and recovery examinations in order to test the precision and accuracy of the analytical procedure. Data for 17 elements (Na, P, K, T, V Cr, Mn, Co, Ni, Cu, Zn, Zr, Pb, Al, F, Ca and Mg) in eight komatiite samples and two USGS basalt reference samples (BCR-2 and BHVO-2) are presented. We evaluate our new digestion and instrumental procedure. The element concentration obtained for BCR-2 and BHVO-2 agreed well with the certified values, the relative standard deviations were lower than 5% and recoveries were good. Our analytical results demonstrate that it reproduces accurately the concentrations of minor and trace elements in komatiites. The ease of digestion of the samples and the speed (less than 12 h) to digest the komatiite material makes this technique an efficient method to be used easily and routinely for preparing and analyzing komatiites samples for multiple elements determination.Peer reviewe

Nitrogen Fixation By Corona Discharge On The Early Precambrian Earth

9 pages, 3 figures.The original publication is available at www.springerlink.comWe report the first experimental study of nitrogen fixation by corona discharge on the anoxic primitive Earth. The energy yields of nitric oxide (NO) and nitrous oxide (N2O) were experimentally determined over a wide range of CO2-N2 mixtures simulating the evolution of the Earth's atmosphere during the Hadean and Archean eras (from 4.5 ba to 2.5 ba). NO, the principal form of fixed nitrogen in lightning and coronal discharge in early Earth, is produced ten times less efficiently in the latter type of electrical discharge with an estimated maximum annual production rate of the order of 10^10 g/yr. For N2O the maximum production rate was estimated to be ∼109 g/yr. These low rates of syntheses indicate that corona discharges as point discharges on the clouds and ground did not play a significant role in the overall pool of reactive nitrogen needed for the emergence and sustainability of life.This paper describes research supported by the National Autonomous University of Mexico (DGAPA-IN102796), the National Council of Science and Technology of Mexico (CONACyT 32531-T), the French-Mexican scientific research program ECOS/CONACyT-SEP-ANNUIES (M97U01).Peer reviewe

Stardust's Hydrazine (N2H4) Fuel: A Potential Contaminant for the Formation of Titanium Nitride (Osbornite)

2 pages.Hundreds of space probes, satellites, and shuttles use ultrapure hydrazine monopropellant for guidance once in orbit. Stardust is the first U.S. mission devoted to exploring a comet and is the first U.S. mission designed to capture samples robotically from a comet and return them to Earth. The spacecraft is equipped with two sets of thrusters that use ultrapure hydrazine as a monopropellant.2,3 One of the biggest scientific surprises of this mission was the detection of tiny (sub-100-nm-size) grains of vanadium-bearing titanium nitride (osbornite).4,5 The use of hydrazine is one of the best significant methods of nitridation, which, precisely, has been used for the specific formation of titanium nitride. Stardust's hydrazine could have acted as a potential contaminant, coreacting with Ti compounds (either from the comet or the spacecraft), for the formation of the titanium nitride (osbornite) particles.Peer reviewe

Experimental impact shock chemistry on planetary icy bodies

15 pages, 14 figures.-- AGU nrs.: 5200, 5400, 5420, 5422, 5455.-- Printed version published on April 2008.The original publication is available at http://www.sciencedirect.com/science/journal/00191035Several icy satellites of the outer planets show impact cratering features and it is recognised that this process may have played a crucial role in the formation and evolution of icy bodies. The effect of impact by extraterrestrial objects into the surface is commonly related to physical changes. Most of the research applied to impacts on ices has been developed to study and understand the cratering formation process and their physical, geophysical characteristics. Chemical changes and synthesis occurring on icy planetary surfaces are generally explained by the influence of UV photons and high-energy charged particles on ices. Nonetheless, impact process onto ices could be a source of local or global endogenic process and could be especially advantageous as an efficient energy source for driving interesting chemistry. Impacts can ensure that icy surfaces are eventually exposed, for a limited period of time, to aqueous melt in impact craters and ejecta and one can imagine that impurities included in the ice may undergo hydrolysis and other reactions under such conditions. Upon impact, the kinetic energy of the bolide is transferred to the ground liberating a great deal of stress energy which could initiate in situ a diverse series of chemical reactions in the fracture zone beneath the crater (Borucki et al., 2002; Jones and Lewis, 1987). Here we present a new approach testing in laboratory the chemistry conducted by impacts into planetary ices and we report the first experimental results. We have irradiated with a powerful pulsed laser icy mixtures of pure water ices containing CO2, Na2CO3, CH3OH and CH3OH / (NH4)2SO4 at 77K. GC-MS and FTIR analyses show that hydrogen peroxide, carbon monoxide and methanol are formed in irradiated H2O / CO2 ices. Ice containing sodium carbonate generates under simulated impact CO and CO2 which are also produced in impacted H2O / CH3OH and H2O / CH3OH / (NH4)2SO4 ices. But, in both latter icy mixtures, methane and more complex molecules are also formed. We have detected acetone, methyl formate and dimethyl formal. Adding ammonium sulfate to ice containing methanol induces the production of N2O, HCN and CH3CN.D.N.-M. was supported by the National Research Council Associateships Program of the National Academies of Science of United States.Peer reviewe