Astronomical tuning of the Aptian stage and its implications for age recalibrations and paleoclimatic events

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Leandro, C. G. ; Savian, J. F. ; Kochhann, M. V. L. ; Franco, D. R. ; Coccioni, R. ; Frontalini, F. ; Gardin, S. ; Jovane, L. ; Figueiredo, M. ; Tedeschi, L. R. ; Janikian, L. ; Almeida, R. P. ; Trindade, R. I. F.

• Document type: Journal article
• Source: NATURE COMMUNICATIONS; v. 13, n. 1, p. 12-pg., 2022-05-26.

Abstract

The Aptian was characterized by dramatic tectonic, oceanographic, climatic and biotic changes and its record is punctuated by Oceanic Anoxic Events (OAEs). The timing and duration of these events are still contentious, particularly the age of the Barremian-Aptian boundary. This study presents a cyclostratigraphic evaluation of a high-resolution multiproxy dataset (delta C-13, delta O-18, MS and ARM) from the Poggio le Guaine core. The identification of Milankovitch-band imprints allowed us to construct a 405-kyr astronomically-tuned age model that provides new constraints for the Aptian climato-chronostratigraphic framework. Based on the astronomical tuning, we propose: (i) a timespan of similar to 7.2 Myr for the Aptian; (ii) a timespan of similar to 420 kyr for the magnetic polarity Chron MOr and an age of similar to 120.2 Ma for the Barremian-Aptian boundary; and (iii) new age constraints on the onset and duration of Aptian OAEs and the 'cold snap'. The new framework significantly impacts the Early Cretaceous geological timescale. (AU)

• FAPESP's process: 16/24946-9 - Sea-level changes and Global Monsoon System: clues from marine cores in Brazil
• Grantee: Luigi Jovane
• Support Opportunities: Research Program on Global Climate Change - Thematic Grants