近日，中国地质大学（武汉）宋海军团队研究了基于贝叶斯锆石喷发年龄和贝叶斯年龄-深度耦合模型的早三叠世年代学。相关论文于2025年10月27日发表在《美国科学院院刊》杂志上。

精确可靠的地质年代学对于重建地球历史及同期生命演化至关重要。早三叠世作为显生宙最大灭绝事件之后的关键时期，记录了显著的生物更替及一系列环境与气候剧变。然而，该时期的地质年代框架仍存在较大争议且约束不足。

研究组基于华南印度阶四个火山灰层的高精度锆石U-Pb测年数据，结合碳同位素记录，采用贝叶斯喷发年龄模型与贝叶斯年龄-深度耦合模型，重新厘定了华南其他四条剖面25个火山灰层的发表年龄，并构建了各剖面新的年龄-深度模型。结合生物地层数据，新模型为下列界线提供了更精确的年龄估算：二叠纪-三叠纪界线（约251.867 Ma）、格里斯巴赫阶-第纳尔阶界线（约251.562 Ma）、印度阶-奥伦尼克阶界线（约250.626 Ma）、史密斯亚阶-斯帕斯亚阶界线（约249.236 Ma）及奥伦尼克阶-安尼阶界线（约246.979 Ma）。

运用新年龄模型对早三叠世碳同位素记录进行校准后，发现各碳同位素漂移事件速率存在显著差异：例如二叠纪-三叠纪界线处的负漂移速率达每10万年约-11.7‰，较史密斯早期负漂移速率（每10万年约-1.7‰）快近七倍。这项精确定年模型还为评估二叠纪-三叠纪大灭绝后生物演化进程提供了可靠的时间框架。

附：英文原文

Title: Geochronology of the Early Triassic based on coupled Bayesian zircon eruption age and Bayesian age–depth models

Author: Dai, Xu, Ovtcharova, Maria, Davies, Joshua H. F. L., Song, Huyue, Liu, Xiaokang, Yuan, Zhiwei, Cao, Yiran, Bai, Ruoyu, Chu, Daoliang, Dal Corso, Jacopo, Brayard, Arnaud, Jiang, Shouyi, Miao, Luyi, Du, Yong, Song, Haijun

Issue&Volume: 2025-10-27

Abstract: Precise and accurate geochronology is essential for reconstructing Earth’s history and coeval life evolution. The Early Triassic was a critical time interval following the greatest Phanerozoic mass extinction, recording remarkable biotic changes and a series of environmental and climatic upheavals. Its geochronology remains, however, rather poorly constrained and highly debated. Here, we present high-precision zircon U-Pb dates for four ash beds from the Induan in South China, along with carbon isotope data. We use coupled Bayesian eruption age and Bayesian age–depth models to estimate the ages of our ash beds and to reinterpret the published ages of 25 ash beds from other four sections in South China, as well as to construct new age–depth models for each section. Our new age–depth models, integrated with biostratigraphic data, yield new age estimates for the following boundaries: Permian–Triassic (~251.867 Ma), Griesbachian–Dienerian (~251.562 Ma), Induan–Olenekian (~250.626 Ma), Smithian–Spathian (~249.236 Ma), and Olenekian–Anisian (~246.979 Ma). Calibration of the Early Triassic carbon isotopic record using the new age model reveals highly variable rates of individual carbon isotope excursions. For instance, the negative excursion across the Permian–Triassic boundary exhibits a rate of approximately 11.7‰ per 100 kyr—nearly seven times faster than the early Smithian negative excursion rate of approximately 1.7‰ per 100 kyr. This refined age model also provides a robust temporal framework to evaluate the tempo of biotic evolution in the aftermath of the Permian–Triassic mass extinction.

DOI: 10.1073/pnas.2509247122

Source: https://www.pnas.org/doi/abs/10.1073/pnas.2509247122