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Accueil du site → Doctorat → États-Unis → 1981 → SURFACE WEATHERING OF ROCKS IN SEMIARID REGIONS AND ITS IMPORTANCE FOR GEOLOGIC REMOTE SENSING

University of Washington (1981)

SURFACE WEATHERING OF ROCKS IN SEMIARID REGIONS AND ITS IMPORTANCE FOR GEOLOGIC REMOTE SENSING

FARR, THOMAS GALEN

Titre : SURFACE WEATHERING OF ROCKS IN SEMIARID REGIONS AND ITS IMPORTANCE FOR GEOLOGIC REMOTE SENSING

Auteur : FARR, THOMAS GALEN

Université de soutenance : University of Washington

Grade : Doctor of Philosophy (PhD) 1981

Résumé
Rock surfaces on Hawaii exposed for as little as 60 years are coated with micrometer-scale clear coatings of almost pure amorphous silica that have sharp contacts with the underlying rock. Older rocks have thicker coatings that include layers of dark fine grained basaltic detritus. Similar coatings are found in volcanic terranes in semiarid regions of the western United States. Based on chemistry and morphology, it appears that these coatings are externally derived. The source of the silica coatings may be local, fine grained, aeolian material or tropospherically transported quartz. The material that makes up the dark parts of the coatings, however is locally derived and affects the spectral reflectance of a rock. Understanding of the geologic parameters affecting types and thicknesses of coatings, combined with knowledge of the reflectance spectra of coated rocks assists in the geologic interpretation of multispectral images of arid and semiarid areas.

Mots clés : Geology, Earth sciences

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