Programa de Pós-Graduação em Geociências, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500, 91501-970, Porto Alegre, RS, Brazil.
Departamento de Geologia, Instituto de Geociências, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500, 91501-970, Porto Alegre, RS, Brazil.
Nat Commun. 2022 May 26;13(1):2941. doi: 10.1038/s41467-022-30075-3.
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 (δC, δO, 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.
阿普第期的特点是剧烈的构造、海洋学、气候和生物变化，其记录被海洋缺氧事件（OAEs）所打断。这些事件的时间和持续时间仍然存在争议，特别是巴雷姆期-阿普第期边界的年龄。本研究对 Poggio le Guaine 岩芯的高分辨率多参数数据集（δC、δO、MS 和 ARM）进行了旋回地层学评估。Milankovitch 波段印记的识别使我们能够构建一个 405 千周年的天文调谐年龄模型，为阿普第期气候地层学框架提供了新的约束。基于天文调谐，我们提出：（i）阿普第期的时间跨度约为 7.2 Ma；（ii）磁极性 Chron M0r 的时间跨度约为 420 kyr，巴雷姆期-阿普第期边界的年龄约为 120.2 Ma；（iii）对阿普第期海洋缺氧事件和“冷 snaps”的开始和持续时间有了新的年龄限制。新的框架对早白垩世地质时标产生了重大影响。
