Astronomical calibration of the latest Aptian to middle Albian in the South Atlantic Ocean

• Published in: Palaeogeography, palaeoclimatology, palaeoecology Vol. 602; p. 111175
• Main Authors: Fauth, Gerson, Krahl, Guilherme, Kochhann, Karlos Guilherme Diemer, Hünnig Bom, Marlone Heliara, Baecker-Fauth, Simone, Bruno, Mauro Daniel Rodrigues, do Monte Guerra, Rodrigo, Ceolin, Daiane, da Silva dos Santos, Alessandra, Villegas-Martin, Jorge, Strohschoen, Oscar, Savian, Jairo Francisco, Leandro, Carolina Gonçalves, de Mello, Raquel Gewehr, de Oliveira Lima, Francisco Henrique
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.09.2022
• Subjects: C34n magnetochron; Dysoxic/anoxic intervals; Early Cretaceous; Eccentricity cycles; Geochemistry; Oceanic Anoxic Event 1b (OAE-1b); Dysoxic/anoxic intervals; Geochemistry; Early Cretaceous; Eccentricity cycles; C34n magnetochron; Oceanic Anoxic Event 1b (OAE-1b)
• ISSN: 0031-0182; 1872-616X
• DOI: 10.1016/j.palaeo.2022.111175

Carbon cycle perturbations dramatically affected the ocean-climate system during the Aptian–Albian transition. However, the chronology of this interval is still intensively debated. Here we present a comprehensive astronomical calibration of planktonic foraminiferal and calcareous nannofossil bioevents along a complete marine sedimentary succession, comprising the latest Aptian to middle Albian interval at drilling Core SER-03, located in the Sergipe-Alagoas Basin. The SER-03 astrochronology is based on the tuning of a high-resolution gamma ray (GR) record to the long eccentricity (405 kyr) metronome, and is integrated with high-resolution paleomagnetic records. Our results span the interval between ~114.7 and 109.5 Ma, within magnetochron C34n, and our age estimates for biostratigraphic markers agree within one long eccentricity cycle with previous estimates. We also present geochemical records, such as stable carbon isotopes (δ13C), organic carbon and carbonate contents, as well as redox-sensitive elemental ratios, measured on bulk sediments at Core SER-03. Most of these proxy records depict marked changes across the Aptian–Albian boundary, likely characterizing the local expression of Oceanic Anoxic Event 1b (OAE 1b), filling the gap for low-latitude records of this event. •The Sergipe-Alagoas Basin recorded the latest Aptian to middle Albian interval at low latitude in the South Atlantic.•Astronomical calibration of planktic foraminifera and calcareous nannofossils international markers (GTS).•Low oxygenation conditions at late Aptian and early Albian interval suggest the presence of the OEA1b onset.