Cathodoluminescence Analysis of Mars Meteorites

INTRODUCTION: The Eyes of EOS Cathodoluminescence (CL) Detection system allows a more complete investigation of specific mineral textures. CL imaging is used to locate and detail the texture, and the CL spectrometer can be used to investigate trace variances found, which then can be correlated with WDS analysis. Specific examples used in defining the texture of Mars Meteorites have been catalogued and some are referenced within this abstract. SAMPLE PREPARATION: Standard polished geological thin sections and 1” round mounts were prepared for electron microprobe use. A thin carbon coating is applied to reduce beam charging. EQUIPMENT: An electron microprobe was outfitted with two CL detection devices mounted within the optical plane. The first one consist of a Black&White phototube with an approximate wavelength range of 320nm to 940nm. The second is a light optic spectrometer with an approximate range of 320nm to 1100nm. IMAGING: Initially a CL image catalogue was produced to document the structure of ALH84001 (Samples N and W), Chassigny*, Nakhla* and Zagami*. This catalogue consisted of optical, backscattered electron (BSE) [Plate 1] and CL [Plate 2] images for easier identification of compositional differences and location within the sample mounts. SPECTRA: CL spectra were gathered to document composition and changes viewed with imaging. As seen in Graph 1, spectral data was gathered to detail the brighter area of the CL image [Plate 3 A]. Graph 2 details the spectra from the gray area [Plate 3