Nanostructure of palygorskite/sepiolite in Texas caliche: Possible bacterial origin

• Autores: Robert L. Folk, E. Troy Rasbury
• Localización: Carbonates and Evaporites, ISSN 0891-2556, Vol. 22, Nº. 2, 2007, págs. 113-122
• Idioma: inglés
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• Resumen

  • In a caliche from west Texas, watermelon-shaped calcite crystals are coated with fibers of palygorskite/sepiolite clay, which also extend out into pore spaces as spiky filaments. Some filaments are smooth and capped by ovoid 30-100nm beads. Other filaments are made of rosary-like chains of beads. These objects are seen both in gold-coated and carbon-coated samples, thus are not artifacts. We suggest that these minute features were cells of nannobacteria (dwarf forms) that precipitated the clay filaments, in a similar manner as larger bacteria that accumulate clay minerals on their negatively-charged cell walls.