Chronostratigraphic constraints and paleoenvironmental interpretation of the Romualdo Formation (Santana Group, Araripe Basin, Northeastern Brazil) based on palynology

Autor(es)

Arai, Mitsuru ^[1] ; Assine, Mario Luis ^[1]

Afiliação do(s) autor(es)

^[1] Univ Estadual Paulista Unesp, Inst Geociencias & Ciencias Exatas, Rio Claro - Brazil

• Tipo de documento: Artigo Científico
• Fonte: CRETACEOUS RESEARCH; v. 116, DEC 2020.
• Citações Web of Science: 1

Resumo

The Santana Group of the Araripe Basin is a major paleontological unit in Brazil, incorporating two important Cretaceous Konservat-Lagerstatten. The lower formations are Aptian, but the age of the uppermost Romualdo Formation has been extended into the Albian. The precise chronostratigraphic position of this upper unit is of considerable significance because the Romualdo Formation records the Cretaceous marine ingression into the interior of Northeastern Brazil, thus playing a significant role in understanding the paleogeography of Gondwana. The main objective of this paper is to establish the chronostratigraphy of the Romualdo Formation based on its most complete section in the Araripe Basin, by determining the occurrence of palynomorphs, in particular establishing the vertical range of the species Sergipea variverrucata, a guide fossil of the Aptian in Brazil. Based on the presence of S. variverrucata, the Romualdo Formation is almost entirely Aptian in age. The palynological assemblage confirms the presence of at least three intervals with marine palynomorphs (dinoflagellate cysts and foraminiferal linings); and a typical regressive pattern towards the top of the Romualdo Formation, evidenced by progressive increase in inaperturate pollen grains (Araucariacites, Uesuguipollgenites and Inaperturopollenites). The palynological data presented herein indicate that the entire Santana Group is of Aptian age because of the conspicuous presence of Sergipea variverrucata and the absence of indisputably Albian forms. Precise dating of the Romualdo Formation signifies that the marine transgression into the interior of northeastern Brazil occurred in the late Aptian, thereby enabling correlation with the sedimentary events recorded in the Brazilian marginal basins. (C) 2020 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 14/00519-9 - Centralidades do lazer noturno na cidade de São Carlos-SP e as relações de interface
• Beneficiário: Tiago Ferreira Lopes Machado
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 04/15786-0 - Reavaliacao da geologia da bacia do araripe, nordeste do brasil.
• Beneficiário: Mario Luis Assine
• Modalidade de apoio: Auxílio à Pesquisa - Regular