Astronomical tuning of the Aptian stage and its implications for age recalibrations and paleoclimatic events.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35618707.
- Also identified by DOI 10.1038/s41467-022-30075-3 and PMC identifier 9135687.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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 (δ<sup>13</sup>C, δ<sup>18</sup>O, 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 ~7.2 Myr for the Aptian; (ii) a timespan of ~420 kyr for the magnetic polarity Chron M0r and an age of ~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.