| Summary: | P(論文) We measured the diffuse reflectance spectra (0.25-2.5μm) of olivine and pyroxene from the ALH-769 ordinary chondrite (L6). We examined the systematic variations of the spectral reflectances of olivine-pyroxene mixtures. We also measured the spectral reflectances for olivine and pyroxene from the olivine sand in Hanauma Bay, Hawaii for comparison. The absolute calibration of the relationship between pyroxene chemistry and absorption band position determined by ADAMS (J. Geophys. Res., 79,4829,1974) is not accurate. The spectral feature of the pyroxene around 1.25μm is sensitive to the existence of the small amount of olivine. This observation does not, however, hold true of the results for the Hawaii clinopyroxene-olivine mixtures. The apparent peak near 0.6μm of the olivine is depressed by the existence of the Hawaii clinopyroxene. The absorption band depth around 2μm is sensitive to the amount of pyroxene. With quantities of pyroxene less than 30%, the wavelength position of the olivine absorption band near 1.05μm shifts drastically. This shift seems to be available for detecting the existence of the small amount of pyroxene in conjunction with the spectral feature around 2μm. It is hoped to examine the systematic variations of the spectral reflectances of two-component mixtures by using the coexisting pair of the minerals which are separated from meteorites (or rocks). departmental bulletin paper
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