Intensified continental chemical weathering and carbon-cycle perturbations linked to volcanism during the Triassic–Jurassic transition

• Published in: Nature communications Vol. 13; no. 1; p. 299
• Main Authors: Shen, Jun, Yin, Runsheng, Zhang, Shuang, Algeo, Thomas J., Bottjer, David J., Yu, Jianxin, Xu, Guozhen, Penman, Donald, Wang, Yongdong, Li, Liqin, Shi, Xiao, Planavsky, Noah J., Feng, Qinglai, Xie, Shucheng
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 13-01-2022; Nature Publishing Group; Nature Portfolio
• Subjects: 140/58; 142/126; 704/106/413; 704/2151/3930; Carbon; Carbon cycle; Carbon dioxide; Carbon isotopes; Clay minerals; Drawdown; Fractionation; Humanities and Social Sciences; Isotopes; Jurassic; Latitude; Mass extinctions; Mercury; Mercury (metal); Minerals; multidisciplinary; Organic carbon; Paleolatitude; Perturbation; Science; Science (multidisciplinary); Triassic; Volcanic activity; Weathering
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-27965-x

Direct evidence of intense chemical weathering induced by volcanism is rare in sedimentary successions. Here, we undertake a multiproxy analysis (including organic carbon isotopes, mercury (Hg) concentrations and isotopes, chemical index of alteration (CIA), and clay minerals) of two well-dated Triassic–Jurassic (T–J) boundary sections representing high- and low/middle-paleolatitude sites. Both sections show increasing CIA in association with Hg peaks near the T–J boundary. We interpret these results as reflecting volcanism-induced intensification of continental chemical weathering, which is also supported by negative mass-independent fractionation (MIF) of odd Hg isotopes. The interval of enhanced chemical weathering persisted for ~2 million years, which is consistent with carbon-cycle model results of the time needed to drawdown excess atmospheric CO
2
following a carbon release event. Lastly, these data also demonstrate that high-latitude continental settings are more sensitive than low/middle-latitude sites to shifts in weathering intensity during climatic warming events.
The work shows that volcanic-related elevated continental chemical weathering could have played a significant role in global environmental perturbations during the Triassic-Jurassic mass extinction.