Ichnological analysis of the Maastrichtian-Danian interval in the Paraíba Basin: Paleoenvironmental insights from the Itamaracá-1IT-03-PE well

• Published in: Journal of South American earth sciences 2024-10, Vol.146, p.105063, Article 105063
• Main Authors: Moreira Júnior, Carlos Alves, Agostinho, Sonia, Andrade, Edilma de Jesus, Barbosa, José Antônio, Franco Neto, Emmanuel, Lima Filho, Mário, Sedorko, Daniel
• Format: Article
• Language: English
• Subjects: Carbonate ramp; Cruziana ichnofacies; Ichnology; K-Pg event
• ISSN: 0895-9811
• DOI: 10.1016/j.jsames.2024.105063

The Gramame and Maria Farinha formations were deposited in the Paraíba Basin during the Maastrichtian-Danian interval, recording the paleoenvironmental evolution during the opening of the Atlantic Ocean. Despite well-investigated, there is still a need to better understand the bioturbation record and the represented ecological conditions during the deposition of these units. This study investigates the ichnofauna of the carbonate facies recorded in the Itamaracá-1IT-03-PE well in the Paraíba Basin, Brazil, focusing on the paleoenvironmental characteristics that influenced this carbonate ramp. The ichnologic analysis allowed to identify environmental stress based on the limited variation in the diversity and complexity. The identified Palaeophycus-Asterosoma and Asterosoma suites suggest low to moderate energy levels, minimal fluctuations in sedimentation rates, and a relatively stress in salinity that persisted for a long period. Variations in δ13C and δ18O values during the Maastrichtian interval corroborates changes in temperature and bioproductivity, reflecting an increase in freshwater influx during this period, which affected paleoenvironmental conditions and trace fossil diversity mainly due to changes in salinity. •Ichnofossil suites from the carbonate ramps and K-Pg boundary.•The trace fossil suites suggest low to moderate energy environments with stable sedimentation rates.•The suites make it possible to identify environmental stress based on the limited variation in the diversity of ichnofossil.