Paleoenvironmental and paleoclimatic interpretation of the Late Cretaceous Marllia Formation (Brazil) based on paleosol geochemistry

Autor(es)

Delgado, L. ^[1] ; Batezelli, A. ^[1] ; Ladeira, F. S. B. ^[2] ; Luna, J. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Campinas, Inst Geosci, Dept Geol & Nat Resources, Source To Sink & Paleopedol Res Grp, Campinas, SP - Brazil

^[2] Univ Estadual Campinas, Inst Geosci, Dept Geog, Source To Sink & Paleopedol Res Grp, Campinas, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: CATENA; v. 180, p. 365-382, SEP 2019.
• Citações Web of Science: 0

Resumo

The Late Cretaceous Marilia Formation located in the central-southern portion of Brazil is characterized by a succession of sandstones, conglomerates, and paleosols. The paleosols constitute more than 60% of this formation, providing significant information about pedogenetic processes as well as paleoenvironmental and paleoclimate implications. The paleosols of the Marilia Formation have been studied principally from a strati graphical, sedimentological and paleopedological point of view; however, there are no studies addressing in detail the geochemical behavior of the paleosols. Therefore, we used a robust geochemical dataset combined with stratigraphical and macromorphological interpretations as well as clay mineralogy to conduct a paleoenvironmental and paleoclimate analysis of the Maxilla Formation in the western portion of the state of Minas Gerais in Brazil. The results indicate that the paleosols of the Marina Formation can be divided into three pedotypes and pedochemical units based on their geochemical variations and are limited at the base and top by pedochemical markers. Moreover, X-ray diffraction identified quartz and calcite as primary minerals associated with montmorillonite, smectite, illite and palygorskite, indicating wet periods combined with dry stages associated principally with dry and arid environments. The paleosol distribution and weathering index allow us to interpret the paleoenvironmental evolution of the Late Cretaceous Marflia Formation, suggesting an increase in humidity from east to west in the study area. (AU)

• Processo FAPESP: 15/17632-5 - Sedimentação e pedogênese das sequencias continentais Cretáceas das bacias Bauru, Sanfranciscana, Parecis e Neuquén.
• Beneficiário: Alessandro Batezelli
• Modalidade de apoio: Auxílio à Pesquisa - Regular