HR: 0800h
AN: P41B-0936    [Abstracts]
TI: Remote Laser Induced Breakdown Spectroscopy (LIBS) of Martian Meteorites and Other Basaltic Samples
AU: * Clegg, S M
EM: sclegg@lanl.gov
AF: Chemistry Division Los Alamos National Laboratory, P.O. Box 1663, MS J565, Los Alamos, NM 87545 United States
AU: Thompson, J R
EM: justinth@usc.edu
AF: International, Space and Response Los Alamos National Laboratory, P.O. Box 1663, MS D466, Los Alamos, NM 87545 United States
AU: Wiens, R C
EM: rwiens@lanl.gov
AF: International, Space and Response Los Alamos National Laboratory, P.O. Box 1663, MS D466, Los Alamos, NM 87545 United States
AU: Barefield, J E
EM: jbarefield@lanl.gov
AF: Chemistry Division Los Alamos National Laboratory, P.O. Box 1663, MS J565, Los Alamos, NM 87545 United States
AU: Vaniman, D T
EM: dvaniman@lanl.gov
AF: Earth and Environmental Sciences Division Los Alamos National Laboratory, P.O. Box 1663, MS D462, Los Alamos, NM 87545 United States
AU: Newsom, H E
EM: newsom@unm.edu
AF: Institute of Meteoritics and Department of Earth and Planetary Sciences University of New Mexico, MSC03-2050 University of New Mexico, Albuquerque, NM 87131 United States
AB: Laser Induced Breakdown Spectroscopy (LIBS) is a rapid and quantitative analytical tool for elemental analysis in terrestrial¹ and Martian environments. LIBS is one of two instruments comprising the "ChemCam" package recently selected for the Mars Science Laboratory (MSL) Rover Mission scheduled to launch in 2009. LIBS will be the first active remote sensing instrument to fly on a NASA rover, designed to interrogate samples to a distance of 9 m. In preparation for the MSL mission, we are working to improve our ability to extract quantitative results under the Martian environment. We recently completed a study in which we extracted quantitative elemental concentrations and calculated the oxide concentrations from two Martian basaltic shergottite meteorites, Dar al Gani (DaG) 476 and Zagami. The current LIBS laboratory setup involves ablating some material from the sample surface with a focused Nd:YAG (1064nm) laser. The ablated material produces a supersonically expanding plasma of electronically excited atoms. A dispersive spectrometer and an ICCD camera are used to record the spectral signatures emitted from the electronically excited atoms. In our experimental set-up, samples were placed at a distance of 5.4 m from the instrument in a vacuum chamber filled with 7 Torr CO₂ to simulate the Martian atmosphere. Terrestrial basalt standards were used to generate calibration curves for all of the major elements and some of the minor and trace species including Si, Fe, Mg, Ca, Ti, Al, and Na. First, two blind basalt standards were analyzed and their compositions were found to match the actual compositions within the uncertainty of the measurement, being correctly distinguished from other available basalt standards. Next, LIBS was used to distinguish between two different basaltic Martian meteorites. Using 14 analysis spots of ~400 μm diameter on DaG 476 and 9 analysis spots on Zagami, LIBS distinguished the olivine-phyric (DaG 476) from the basaltic (Zagami) shergottite on the basis of MgO and CaO. The elemental abundances agreed with literature values for these meteorites to within ~5% for most of the major elements. We are continuing studies of the laser ablation process and its effects on the material in and around the laser pit. ¹Ebinger, Harris, Ploss and Clegg, Advanced Method for In-Field Measurement, Monitoring and Verification of Total Soil Carbon, 2005 AGU Meeting
DE: 5400 PLANETARY SCIENCES: SOLID SURFACE PLANETS
DE: 5464 Remote sensing
DE: 5470 Surface materials and properties
DE: 5494 Instruments and techniques
SC: Planetary Sciences [P]
MN: Fall Meeting 2005