Climate-forced Hg-remobilization associated with fern mutagenesis in the aftermath of the end-Triassic extinction
Remco Bos, Wang Zheng, Sofie Lindström, Hamed Sanei, Irene Waajen, Isabel Fendley, Tamsin A. Mather, Yang Wang, Jan Rohovec, Tomáš Navrátil, Appy Sluijs, Bas van de Schootbrugge
Abstract
Abstract The long-term effects of the Central Atlantic Magmatic Province, a large igneous province connected to the end-Triassic mass-extinction (201.5 Ma), remain largely elusive. Here, we document the persistence of volcanic-induced mercury (Hg) pollution and its effects on the biosphere for ~1.3 million years after the extinction event. In sediments recovered in Germany (Schandelah-1 core), we record not only high abundances of malformed fern spores at the Triassic-Jurassic boundary, but also during the lower Jurassic Hettangian, indicating repeated vegetation disturbance and stress that was eccentricity-forced. Crucially, these abundances correspond to increases in sedimentary Hg-concentrations. Hg-isotope ratios (δ 202 Hg, Δ 199 Hg) suggest a volcanic source of Hg-enrichment at the Triassic-Jurassic boundary but a terrestrial source for the early Jurassic peaks. We conclude that volcanically injected Hg across the extinction was repeatedly remobilized from coastal wetlands and hinterland areas during eccentricity-forced phases of severe hydrological upheaval and erosion, focusing Hg-pollution in the Central European Basin.