New marine data and age accuracy of the Romualdo Formation, Araripe Basin, Brazil

Robbyson Mendes Melo,Ariany De Jesus E Sousa,Enelise Katia Piovesan,Virgínio Henrique De Miranda Lopes Neumann,Débora Almeida-Lima,Juliana Guzmán

doi:10.1038/s41598-020-72789-8

Robbyson Mendes Melo, Ariany De Jesus E Sousa + Show 4 more

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https://doi.org/10.1038/s41598-020-72789-8

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Abstract

A combined biostratigraphic and palaeoecological study of foraminifera, ostracodes and microfacies was carried out on the Aptian in the Sítio Sobradinho section of the Araripe Basin, northeast Brazil. The analysed section represents a deepening-upward sequence with mid-ramp shoal and outer ramp to basin facies associations on a mixed siliciclastic-carbonate marine ramp. The analysed rocks are dominated by Early Cretaceous planktic foraminifera (Hedbergella aptiana, H. praelippa, H. sigali, Blesfucuiana cf. cumulus, Microhedbergella miniglobularis, Gorbachikella cf. kugleri, Pseudoguembelitria blakenosensis, Globigerinelloides clavatus, Globigerinelloides aff. aptiensis, Gubkinella sp. and Loeblichella sp.). Ostracoda fauna is composed mainly of Pattersoncypris crepata and Pattersoncypris micropapillosa. The occurrence of P. crepata associated with the Aptian planktic foraminifera demonstrates the potential of this ostracode species to date this interval. The planktic foraminifera from the upper Aptian (Microhedbergella miniglobularis Zone) of the Araripe Basin show characteristical Tethyan affinities.

Highlights

Several intracratonic and marginal basins of eastern South America and western Africa record the opening of the South Atlantic as a large Jurassic–Cretaceous intraplate rift zone during the break-up of western Gondwana
According to Heine et al.[28], SW-directed extension had already started during the latest Jurassic in the southern part of the South Atlantic Rift System; in addition, break-up and seafloor spreading started near 138 Ma, during which time E–W-directed extension between South America and Africa occurred at very low extensional velocities until the Hauterivian (~ 126 Ma), when rift activity in the equatorial Atlantic started to increase significantly with significant rotation towards NE–SW
To constrain the chronostratigraphic position of this interval, we report robust marine data from the Romualdo Formation represented by a set of microfossils, including planktic and benthic foraminifera, ostracodes and calcispheres of Early Cretaceous age from the Araripe Basin

Summary

Introduction

Several intracratonic and marginal basins of eastern South America and western Africa record the opening of the South Atlantic as a large Jurassic–Cretaceous intraplate rift zone during the break-up of western Gondwana. Fluvial and lacustrine environments characterize most of the strata that comprise the Araripe Basin Mesozoic record, but at the top of the succession, the evaporitic Ipubi Formation and the marine fossil content of the Romualdo Formation allow the Scientific Reports | (2020) 10:15779. To constrain the chronostratigraphic position of this interval, we report robust marine data from the Romualdo Formation represented by a set of microfossils, including planktic and benthic foraminifera, ostracodes and calcispheres of Early Cretaceous age from the Araripe Basin. The significance of this study lies in the calibration of Aptian planktic foraminiferal events with ostracode species

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