ABSTRACT
This chapter presents the general aspects of the Ventura basin soil chronosequence, and considers its usefulness. Soils evolve as a result of a complex interaction of many natural processes which tend to both augment and retard horizonation of the soil profile. The soils developed on alluvium in the Ventura basin are principally Entisols, Inceptisols, Mollisols and Alfisols. A soil chronosequence comprising seven primary members ranging in age from 200 000 years bp to the present has been studied and dated for the Ventura basin region. Good temporal control on the chronosequence allows, in most cases, undated deposits with intact soils to be assigned tentative age ranges. This is particularly important in assessing rates of active deformation when active faulting or folding deforms deposits that contain no radiometrically datable material. In all cases, caution must be taken to ensure that the soil is in a stable geomorphic position and that soil regression has not occurred.
