Chemical weathering of basalts and andesites; evidence from weathering rinds

Abstract

Weathering rinds on basaltic and andesitic stones preserve the alteration products of these lithologies under conditions that preclude detrital contamination, physical removal, and uncertainty of original composition. The mineralogy and chemistry of samples of weathering rinds on andesitic and basaltic stones from several areas with temperate climates in the Western United States were studied using a variety of analytical methods, including thin-and polished sections, X-ray diffraction, differential thermal analysis, scanning electron microscopy, X-ray energy spectrometry, and bulk chemical analysis.