Agradecimentos: We thank Coordination for the Improvement of Higher Education Personnel (CAPES) for the doctorate scholarship, The São Paulo Research Foundation (FAPESP) for funding the project 2015/17632-5 process (Sedimentation and pedogenesis of the Cretaceous continental sequences of the Bauru, Sanfranciscana, Parecis and Neuquén basins) and National Council for Scientific and Technological Development (CNPq) for funding the project 431184/2016-0 process (Long-Term Geomorphological Evolution: Cretaceous and paleogenic history of denudation, genesis of sedimentary basins and landforms), as well as CNPq for the productivity scholarship for the second author (308629/2015-9 and 307951/2018) and Programa de Excelência Acadêmica (Proex)-CAPES support Ver menos

Abstract: A study of paleosols with argillic horizons found in the Marília Formation associated with Maastrichtian in the Cretaceous is presented herein. This study aims to investigate the polygenetic processes involved in argillic horizon formation under paleoclimatic conditions from arid to semiarid in the Brazilian Cretaceous and considers morphological soil attributes, such as evidence of cementation, macromorphological data (horizons, matrix color, structure, clay coatings, nodules, and bioturbations), micromorphological data (coarse/fine patterns, b-fabric, clay coatings, infillings, and nodules), and water table oscillation. Seven representative profiles of paleosols were selected in the São Paulo state, Brazil, and soil samples of lithified paleosols were collected to determine their macromorphological–micromorphological and chemical properties. Clay illuviation, carbonate accumulation, and gleization were dominant processes in the paleosols. Clay illuviation was identified from clay coatings along grain and ped surfaces. Carbonates occurred as nodules and rhizoliths and as coatings on peds. Red mottles, gray rhizohaloes with red oxidation rims, oxidic nodules, an iron-depleted matrix, and iron oxide depletion hypocoatings confirmed gleization. The argillic horizon polygenesis in the Marília Formation is usually interpreted as evidence of high-moisture events under arid/semiarid climates or climate change toward moister conditions than arid/semiarid. Thus, argillic horizon paleosols in the sedimentary records of the Marília Formation are not necessarily reliquial characteristics of wet paleoenvironments but are associated with changes in dominant granulometry, types of macroaggregates–microaggregates, carbonate accumulation in horizons, and/or water table oscillation. Thus, the presence of Bt horizons does not necessarily imply wet conditions with changes in the depositional system, as proposed by some authors Ver menos