Neoformation of palygorskite in a southern New Mexico aridisol

TitleNeoformation of palygorskite in a southern New Mexico aridisol
Publication TypeJournal Article
Year of Publication1991
AuthorsH. Monger C, Daugherty L.A
JournalSoil Science Society of America Journal
Date Published1991
Call Number00641
Keywordsarticle, articles, calcite, geomorphology, petrocalcic horizon, geomorphology,palygorskite formation, journal, journals, palygorskite formation, soil, palygorskite formation, soil, petrocalcic horizon
Abstract Palygorskite is the dominant clay mineral in a petrocalcic horizon of the Rotura soil series (a coarse-loamy, mixed, thermic, Typic Haplargid), a soil of middle Pleistocene age in southern New Mexico. The purpose of this study was to determine if palygorskite is eolian in origin, inherited from its alluvial parent material, or neoformed in the soil. The origin of palygorskite was determined by examining clay mineral distribution, soil-water extract chemistry, and palygorskite fiber morphology. An eolian origin of palygorskite is unlikely because it is absent in upper soil horizons and no palygorskite was captured in dust traps during a 10-yr study. An inherited origin is also unlikely because palygorskite is not an inherent component of Rio Grande alluvium. Scanning electron microscopy revealed that delicate palygorskite fibers radiate perpendicularly into pore spaces, which indicates neoformation. The petrocalcic horizon may foster palygorskite neoformation because it is the site of high Mg content and abundant sand- and silt-grain dissolution.