Regolith LANDSAT-8/OLI and Hyperion/EO-1 images classification in midwest of Brazil

Abstract

The orbital LANDSAT-8/OLI sensor and SRTM altimetric images combined with Boolean algebra and complemented by fieldwork and XRD, chemical and spectroradiometric analysis, allowed to develop a mathematical model for mapping the tropical regolith in the Midwest of Brazil. It was used four mapping classes following the arithmetic band operations of 4/2 and (4+6)/5 to identify lateritic duricrusts, loosed iron concretions, nodules and pisoliths, (6/7)/(5/4) to parent rock, saprolite, mottled horizon and soil, and (5–4)/(5+4) to vegetation.Hyperspectral Hyperion/EO-1 image endorse the mathematical model identifying the pure pixels of kaolinite, goethite, and hematite in the lateritic duricrusts, loosed iron concretions, nodules and pisoliths occurrence pixels.Narrow and low reflectance spectroscopy concavity between 400 and 600 nm and a broad medium concavity between 800 and 1100 nm are the typical spectral features of the study lateritic duricrusts, highlighting the strong influence of the goethite and hematite contents.The development of these LANDSAT-8/OLI and Hyperion/EO-1 classification models and the identification of the specific reflectance spectroscopy features for the tropical lateritic terrains, provide a more precise regolith-geological architecture. It is very helpful for mineral exploration, for developed strategies for understanding the regolith landscape better and how surficial geochemical anomalies are formed, and for geomorphology interpretation in deeply weathered regions.