Spectral reflectance of carbonatites and related alkalic igneous rocks: selected samples from four North American localities.

Abstract

Laboratory spectra in the 0.4-2.5 mu m wavelength range are reported and discussed for 1 cm2 samples of carbonatites and associated rocks from Mountain Pass, California; Oka, Quebec; Iron Hill, Colorado; and Gem Park, Colorado. The carbonatites showed carbonate, iron, and - locally - REE absorption bands. Reflectance measurements are notably sensitive to inherent compositional variations and to the effects of weathering and iron staining, but are useful for detecting high REE contents, and possibly in remote sensing applications, for detecting carbonatite bodies.-G.J.N.