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Brazilian Cretaceous paleoclimates: evidence from clay minerals, sedimentary structures and palynomorphs

1983; Sociedade Brasileira de Geologia; Volume: 13; Issue: 4 Linguagem: Inglês

10.25249/0375-7536.1983134215222

2177-4382

Setembrino Petri,

Geochemistry and Geologic Mapping

This paper deals with the paleoclimatic inferences on the Brazilian Cretaceous formations derived from the interpretation of sedimentary structures, clay-minerals and palynomorphs. Hot climates were predominant during the period. The palynomorphs suggest a rather cooling episode in Late Wealdean and Late Maestrichtian though not cooler than a subtropical climate. The clayminerals and sedimentary structures of the Late Maestrichtian formations do not support an inference of a great deal of cooling in Late Maestrichtian times. Humid climates were the rule during Wealdean. Dry climates are well documented in Late Aptian times and dry climates may have lasted till Cenomanian. The driest climates may have occurred in Late Albian according to the palynomorphs. Santonian to Maestrichtian witnessed predominant humid climates in coastal regions but rather drier climates inland.