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Calcareous nannofossils, biostratigraphy, and paleobiogeography of the Aptian/Albian Romualdo Formation in the Araripe Basin, North-Eastern Brazil.

Authors :
Azevedo Pedrosa Lemos, Flávia
Yumi Asakura
Antunes, Rogério Loureiro
Cardoso de Araripe, Rilda Verônica
Alves Cadeira do Prado, Ludmila
Travassos Rio Tomé, Maria Emilia
Holanda de Oliveira, David
Silva Lobo do Nascimento, Luiz Ricardo
Ng, Christiano
Franca Barreto, Alcina Magnólia
Source :
Brazilian Journal of Geology. 2023, Vol. 53 Issue 2, p1-13. 13p.
Publication Year :
2023

Abstract

The objectives of this study were the biostratigraphic and paleobiogeographic interpretations of the calcareous nannofossil records of the Romualdo Formation (Aptian-Albian) in the south-central portion of the Araripe Basin. The methods used to process the samples were decanting, smear slide, centrifugation, and ultra-thin section confection. The taxonomic and biostratigraphic interpretations were carried out through qualitative and quantitative investigations. A total of 11 genera and 17 species of calcareous nannofossils, namely, Biscutum constans, Biscutum sp., Braarudosphaera africana, Braarudosphaera sp., Calculites sp., Discorhabdus ignotus, Hayesites albiensis, Hayesites sp., Nannoconus bucheri, Nannoconus sp., Retecapsa surirella, Rhagodiscus sp., Thoracosphaera sp., Watznaueria barnesiae, Watznaueria sp., Zeughrabdotus erectus, and Zeughrabdotus noeliae were identified. The integrated analysis of three outcrops suggests two distinct marine phases: the first in the Aptian, recognized in two outcrops, and during the Albian age. The genera Hayesites and Nannoconus suggest a strong Tethyan affinity. Differently, other calcareous nannofossils such as Watznaueria, Thoracosphaera, and Braarudosphaera recorded here are considered more resistant, cosmopolitan, and/or opportunistic species. Biscutum and Zeughrabdotus are sensitive calcareous nannofossils because they are more susceptible to dissolution and cannot be surely used to define this paleobiogeography and biostratigraphic range. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
23174889
Volume :
53
Issue :
2
Database :
Academic Search Index
Journal :
Brazilian Journal of Geology
Publication Type :
Academic Journal
Accession number :
177508771
Full Text :
https://doi.org/10.1590/2317-4889202320220054