The Barreiras Formation possesses soils with horizons and subsurface layers cemented by Si, Al and Fe and commonly enriched with organometallic compounds, which show current and past podzolization processes. The study of these horizons and cemented layers can assist in understanding pedogenesis and paleoenvironmental evolution. Three soil profiles were selected along a toposequence for which morphological and micromorphological descriptions were made and samples of organic matter from spodic horizons and cemented layers were dated using carbon isotopes (12C, 13C, 14C), with the aim of obtaining records of paleoenvironmental conditions and understanding the genetic chronology of the soils. The results were interpreted considering three premises: (i) podzols develop under predominantly humid climatic conditions; (ii) organic matter enclosed in cemented horizons is fossilized and provides data regarding the chronological record of cementation time; and (iii) analysis of fossil plant organic residues using the 13C/12C ratio (δ13C) provides an indication of paleo-vegetal coverage. The results indicate that there were two distinct podzolization events in the study area under humid climatic conditions because the area was dominated by tree vegetation according to δ13C, which ranged from −27.2 %o to −25.3 %o. The first, and oldest, podzolization event, related to the range of 17,530–14,970 years BP, reached all three soil profiles, while the second, younger, event started around 6430 years BP, and is registered only in the upper part of the cemented layer of the P-10 profile located at the top of the slope. Combining the results of organic matter dating with morphological and micromorphological analyses of the profiles leads to the conclusion that the P-10 profile is developing on a cemented bedrock and the P-13 and P-15 profiles are developing on two bedrocks — superficial horizons arising from colluviums coming from the top of the slope and subsurface horizons developing from cemented material.