2020/07/31 by Brian D. Fields, Adrian L. Melott, John Ellis +8 · 2 citations
Earth and Planetary Sciences · Physics and Astronomy · #Astro and Planetary Science #Paleontology and Stratigraphy of Fossils #Planetary Science and Exploration #astro-ph.HE #astro-ph.SR #physics.geo-ph
paper · pdf · doi:10.1073/pnas.2013774117
published as PNAS 117, 35, 21008-21010 (2020) · 3 pages, no figures. Matches published version. Creative Commons CC BY-NC-ND license
openalex publication_date 2020/08/18 · arxiv created 2020/08/25 · arxiv updated 2020/09/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The Late Devonian was a protracted period of low speciation resulting in biodiversity decline, culminating in extinction events near the Devonian-Carboniferous boundary. Recent evidence indicates that the final extinction event may have coincided with a dramatic drop in stratospheric ozone, possibly due to a global temperature rise. Here we study an alternative possible cause for the postulated ozone drop: a nearby supernova explosion that could inflict damage by accelerating cosmic rays that can deliver ionizing radiation for up to ∼ 100 kyr. We therefore propose that the end-Devonian extinctions were triggered by supernova explosions at ∼ 20 pc, somewhat beyond the "kill distance" that would have precipitated a full mass extinction. Such nearby supernovae are likely due to core-collapses of massive stars; these are concentrated in the thin Galactic disk where the Sun resides. Detecting either of the long-lived radioisotopes Sm-146 or Pu-244 in one or more end-Devonian extinction strata would confirm a supernova origin, point to the core-collapse explosion of a massive star, and probe supernova nucleosythesis. Other possible tests of the supernova hypothesis are discussed.