Use of soils and palaeosols on volcanic materials to establish the duration of soil formation at different chronological scales

Abstract In this paper, we present an overview of the Mexican volcanic palaeosol sequences, as a valuable tool to establish the duration of soil formation at different chronological scales. We have selected four study cases which cover time intervals from decennial, centennial, to millennial pedogenesis. The first case corresponds to the soils in El Chichon volcano, where the short interval between the eruptions gives the opportunity to study the soil formation in periods less than 500 years. In this interval, the transformation from Regosol to Andosol is observable. In El Nevado de Toluca, pedogenesis of longer duration (4000 to 6000 y), characterizes a vitric Andosol stage. In this area, the transformation of Andosol to Luvisol is also shown, in periods longer than 10,000 years. The third study case corresponds to the Tlaxcala palaeosol sequence, where pedogenesis in intervals from 10,000 to 100,000 years is observable. In this case, no Andosols are present, and a complete set of Luvisols showing different properties is found. This differentiation is not only related to the duration of the pedogenesis, but also to the climatic conditions, which lead to changes in specific properties (clay content, weathering of the primary minerals, Fed content). In this way, these soils are valuable for palaeoenvironmental reconstruction. The fourth case is related to faster pedogenesis in the volcanic regions of Mexico, where highly developed Luvisols are found, formed in intervals less than 15,000 y. In this case, the influence of a pre-weathered volcanic material as a source of clay allows the rapid transformation.