High-precision timeline for Earth's most severe extinction

Area of Science:

• Paleontology
• Geochronology
• Geochemistry

Background:

• The end-Permian mass extinction represents the most catastrophic loss of marine and terrestrial life in the last 542 million years.
• Establishing an accurate age model is crucial for understanding the extinction's causes and recovery dynamics.

Observation:

• High-precision U-Pb zircon dating of volcanic ash beds at the Permian-Triassic boundary GSSP in Meishan, China, provides a refined age model.
• The extinction interval is precisely dated between 251.941 ± 0.037 and 251.880 ± 0.031 Mya, lasting 60 ± 48 ka.
• A significant carbon cycle reorganization, marked by a sharp negative carbon isotope excursion, immediately preceded the extinction's onset.

Findings:

• The mass extinction occurred within a geologically short timeframe of approximately 60,000 years.
• Carbon cycle volatility persisted for about 500,000 years post-extinction.
• Millennial-scale resolution reveals the timing of extinction relative to environmental perturbations and carbon cycle disruption.

Implications:

• This precise age model allows for a refined evaluation of rate-dependent processes contributing to the extinction.
• It provides critical insights into the mechanisms driving mass extinctions and subsequent ecosystem recovery.
• The findings enable a more accurate assessment of potential trigger and kill mechanisms for the end-Permian event.