Globally Enhanced Hg Deposition and Hg Isotopes in the K/Pg and PT Boundaries: Link to Volcanism

Abstract

Mercury (Hg/TOC) spikes from eight classical PTB sections display similar patterns across the extinction interval. At Meishan, these spikes are in the LPME and ETME while at Hovea-3, Ursula Creek, Idrijca and Rizvanu š a they are at the LPME and PTB. The Rizvanu š a section displays one peak at the ETME; Zal and Abadeh sections, at the LPME and ETME, while Misci shows enrichment at the LPME. Three Hg/TOC spikes are seen in the Stevns Klint, Gubbio, Um Sohringkew and Poty K/Pg sections: spike I within the CF2 biozone, spike II at the K/Pg boundary layer, and spike III within the P1a subzone. In a δ 202 Hg (MDF) vs ∆ 201 Hg (MIF) plot, most samples from the PT extinction interval lie within the volcanic-emission box. Hg-isotope signatures resulted from mixing of volcanic and normal marine sediment Hg, generating four trends whose ∆ 201 Hg show negligible variation. Rizvanu š a, Idrijca and Misci sections, closer to the STLIP,