Synchronous end-Permian mass extinction zenith in marine and low-middle latitude terrestrial North China.

A high-resolution chronostratigraphic framework from North China places a Hg peak at 252.4 Ma and carbon-isotope excursion onset at 252.1 Ma at the end-Permian extinction zenith.

• Why it matters: Temporal synchrony between marine and terrestrial end-Permian extinctions is debated because correlation uncertainties limit how precisely events can be aligned across environments.
• What they did: Integrated magnetostratigraphy, cyclostratigraphy, and carbon-isotope and mercury chemostratigraphy were built for the Sigou section (Upper Shihhotse, Sunjiagou, Liujiagou formations), identifying 14 magnetozones from late Changhsingian to late Olenekian.
• The result: The Hg peak at 252.4 Ma aligns with the Siberian Traps main eruptive phase, while the carbon isotope excursion onset (252.1 Ma) and minimum (252.0 Ma) match the Meishan GSSP, constraining the Induan Stage duration to 1.6–1.8 My and supporting a synchronous extinction zenith across marine and low-middle latitude terrestrial ecosystems.