Genesis and paleoclimatic significance of palygorskite in the cretaceous paleosols of the Bauru Basin, Brazil

- Field interpretations and analytical determinations suggest pedogenic origin for the calcretes of the Marília Formation.
- The palygorskite, associated with calcite and smectites, is of pedogenic environment, developed in semi-arid climate.
- In the Maastrichtian of the Bauru Basin, the origin of palygorskite occurs under three polygenetic types (P, P1 and P2).
- Three factors determine the polygenesis of palygorskite in the paleosols of the Marília Formation.