Spectral deconvolution analysis on Olivine-Orthopyroxene mixtures with simulated space weathering modifications

Abstract

Olivine and pyroxene are important mineral end-members for studying the surface material compositions of mafic bodies. The profiles of visible and near-infrared spectra of olivine-orthopyroxene mixtures systematically vary with their composition ratios. In our experiments, we combine the RELAB spectral database with new spectral data obtained from some assembled olivine-orthopyroxene mixtures. We found that the commonly-used band area ratio (BAR, Cloutis et al.) does not work well on our newly obtained spectral data. To investigate this issue, an empirical procedure based on fitted results by a modified Gaussian model is proposed to analyze the spectral curves. Following the new empirical procedure, the end-member abundances can be estimated with a 15% accuracy with some prior mineral absorption features. In addition, the mixture samples configured in our experiments are also irradiated by pulsed lasers to simulate and investigate the space weathering effects. Spectral deconvolution results confirm that low-content olivine on celestial bodies is difficult to measure and estimate. Therefore, the olivine abundance of space weathered materials may be underestimated from remote sensing data. This study may be utilized to quantify the spectral relationship of olivine-orthopyroxene mixtures and further reveal their correlation between the spectra of ordinary chondrites and silicate asteroids.