COMPARATIVE STUDY OF VERTISOL AND ALFISOL SOIL CHRONOSEQUENCES AT THE CONFLUENCE OF THE BRAZOS AND BOSQUE RIVERS IN CENTRAL TEXAS

Currently, soil chronosequences within central Texas are scarce and those that do exist are poorly constrained in time. In this study, two dated chronosequences for the floodplain and terraces of the Brazos and Bosque Rivers in Waco, Texas was created using optically stimulated luminescence (OSL). The development of Alfisols and Vertisols was observed in parallel in this location over time. The chronosequences represent clayey, carbonitic alluvium from the Bosque River (Mollisols to Vertisols) and loamy, weakly carbonitic alluvium from the Brazos River (Entisols to Alfisols). Both shows physical and chemical changes over time, with loamy soils showing greater changes in physical properties and clayey soils exhibiting strong trends in mobile CEC with depth and age.