Abstract

ESCAMILLA SARABIA, Guadalupe; SOLLEIRO REBOLLEDO, Elizabeth; SEDOV, Sergey  and  GAMA CASTRO, Jorge. Tepetates from The Buenavista Glacis, Morelos: interaction between geomorphic and pedogenetic processes. Invest. Geog [online]. 2002, n.48, pp.76-89. ISSN 2448-7279.

A study of tepetates found in the Glacis de Buenavista, Morelos is hereby presented. The section of study (Ahuatenco) includes a sequence of seven indurate horizons (tepetate layers), underlying a polygenetic and well-developed Luvisol. In this work tepetates are considered as products of erosion-sedimentation and pedogenetic processes. Therefore they are interpreted as paleosols with different degrees of development. Macro and micromorphologic evidences indicate that the tepetate profile is constituted by a mixture of fresh coarse volcanic material, redeposited fragments of soil and pedogenetic features, which include: clay cutans, Fe-Mn nodules, weathered primary minerals and phytoliths accumulated within the layer matrix. These properties show that tepetates were exposed at the surface for a sufficient time to allow pedogenesis. The tepetates' parent material are volcanic ashes derived from volcanic events, and eroded Bt-horizon remains from the upper portions that were redeposited along with volcanic materials. Because of the presence of these Bt-horizon fragments the clay content in indurate materials is high (47%), but they display a contrasting distribution, showing lithological and textural discontinuities, so each layer is likely to represent a different stage of landscape evolution. The degree of alteration observed for the different layers vary, as well as the stability periods under which pedogenesis occurs.

Keywords : Tepetates; paleosols; pedogenesis.