Supernova triggers for end:Devonian extinctions

TY - JOUR

T1 - Supernova triggers for end:Devonian extinctions

AU - Fields, Brian D.

AU - Melott, Adrian L.

AU - Ellis, John

AU - Ertel, Adrienne F.

AU - Fry, Brian J.

AU - Lieberman, Bruce S.

AU - Liu, Zhenghai

AU - Miller, Jesse A.

AU - Thomas, Brian C.

PY - 2020/9/1

Y1 - 2020/9/1

N2 - 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 ky. 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 146Sm or 244Pu 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 nucleosynthesis. Other possible tests of the supernova hypothesis are discussed.

AB - 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 ky. 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 146Sm or 244Pu 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 nucleosynthesis. Other possible tests of the supernova hypothesis are discussed.

KW - Extinction | Supernova | Cosmic rays | Ozone | Isotope geology

UR - http://www.scopus.com/inward/record.url?scp=85090507887&partnerID=8YFLogxK

U2 - 10.1073/pnas.2013774117

DO - 10.1073/pnas.2013774117

M3 - Article

C2 - 32817482

AN - SCOPUS:85090507887

SN - 0027-8424

VL - 117

SP - 21008

EP - 21010

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

IS - 35

ER -