Identification of kaolins and associated minerals in altered volcanic rocks by infrared spectroscopy

Mid-infrared spectroscopy (2.5-50 /µm) has been extensively used to identify and characterize clays and associated minerals in rocks and soils, with particular emphasis on the 3-, 10-, and 20-/µm regions (Farmer and Russell, 1967; Farmer, 1968; White, 1971; Van der Marel and Beutelspacher, 1976). However, application of mid-infrared spectroscopy in remote-sensing activities has been restricted because the spectral information occurs only as a small perturbation to the emitted radiation from the earth's surface, and much of that which is especially relevant to clays (e.g., the 3.0-µm region) is obscured by atmospheric absorption.