Problems and concepts of paleopedology in Argentina

Pedogenesis has played a major role in the evolution of the Pampean landsca pe which resulted in the common occurrence of pedogenic features in the str atigraphic successions, but has not been recognized in previous studies. Th e main problems facing paleapedological research are the identification of paleosol profiles, paleosol horizons and their interpretation. Paleosols ha ve been traditionally interpreted as truncated profiles because A and E hor izons were not recognized. This may be apparent or real. Erosion generally leaves supporting evidence such as a lag deposit, but superposed cycles of pedogenesis can obliterate original morphological properties. which alters the appearance of buried A and E horizons. Abrupt boundaries have always be en interpreted as erosional surfaces because of an overgeneralization that all land surfaces are eroded. When paleosols are exposed in roadcuts and qu arries, they acquire new morphological features such as induration and tens ion cracks, which have been misinterpreted as original properties. In the c urrent view, the basic criteria for paleosol recognition in exposures are b ased on the vertical and lateral arrangements of soil morphological Feature s within a detailed stratigraphic framework provided by sedimentary facies analysis. The framework can be verified by micromorphological studies of po lygenetic horizons to determine the sequence of episodes of pedogenesis and to evaluate the effects of diagenesis following burial. (C) 1998 INQUA/Els evier Science Ltd. All rights reserved.