Nickel isotopes link Siberian Traps aerosol particles to the end-Permian mass extinction

Abstract

The end-Permian mass extinction (EPME) was the most severe extinction event in the past 540 million years, and the Siberian Traps large igneous province (STLIP) is widely hypothesized to have been the primary trigger for the environmental catastrophe. The killing mechanisms depend critically on the nature of volatiles ejected during STLIP eruptions, initiating about 300 kyr before the extinction event, because the atmosphere is the primary interface between magmatism and extinction. Here we report Ni isotopes for Permian-Triassic sedimentary rocks from Arctic Canada. The δ⁶⁰Ni data range from -1.09‰ to 0.35‰, and exhibit the lightest δ⁶⁰Ni compositions ever reported for sedimentary rocks. Our results provide strong evidence for global dispersion and loading of Ni-rich aerosol particles into the Panthalassic Ocean. Our data demonstrate that environmental degradation had begun well before the extinction event and provide a link between global dispersion of Ni-rich aerosols, ocean chemistry changes, and the EPME.

Fig. 1. Regional map showing the location of the study area in Arctic Canada (after ref. ).

A Regional map. B Detailed map showing the location of the Buchanan Lake section. C Permian palaeogeographic map showing the location of the Sverdrup Basin relative to the Siberian Traps volcanic rocks (base map after C.R. Scotese [http://www.scotese.com/]). Wavy arrows indicate predominant westerly wind patterns.

Fig. 2. Nickel isotopic compositions and Ni contents of black shales in the Buchanan Lake section.

Error bars represent 2 s.d. The C-isotope chemostratigraphy is from ref. and shaded areas refer to fly coal ash loading events reported in ref. . Palaeo-redox conditions are from refs. ^, and U-Pb age for the EPME horizon is from ref. .

Fig. 3. Summary of the Ni isotopic compositions reported in this study and previously published data.

Rivers and the global ocean are from ref. , and Fe–Mn crusts are from refs. ^,. Carbonates and OMZ sediments are from ref. . Magmatic sulphides are from refs. ^,. Organic-rich black shale and mudstone are from ref. and sulphidic Black Sea sediments are from ref. . The comparable light Ni isotopic compositions between the magmatic sulphides and our data are highlighted in orange.

Fig. 4. Schematic illustration linking the atmospheric and ocean chemistry changes triggered by the STLIP to the EPME (not to scale).

The C-isotope chemostratigraphy and coal ash loading events are from ref. and Hg anomalies are from ref. . Palaeo-redox conditions are from refs. ^,.