Alongside the Chicxulub meteorite impact, Deccan volcanism is considered a primary trigger for the Cretaceous–Paleogene (K–Pg) mass extinction. Models suggest that volcanic outgassing of carbon and sulfur—potent environmental stressors—drove global temperature change, but the relative timing, duration, and magnitude of such change remains uncertain. Here, we use the organic paleothermometer MBT′ 5me and the carbon-isotope composition of two K–Pg-spanning lignites from the western Unites States, to test models of volcanogenic air temperature change in the ~100 kyr before the mass extinction. Our records show long-term warming of ~3°C, probably driven by Deccan CO 2 emissions, and reveal a transient (<10 kyr) ~5°C cooling event, coinciding with the peak of the Poladpur “pulse” of Deccan eruption ~30 kyr before the K–Pg boundary. This cooling was likely caused by the aerosolization of volcanogenic sulfur. Temperatures returned to pre-event values before the mass extinction, suggesting that, from the terrestrial perspective, volcanogenic climate change was not the primary cause of K–Pg extinction.

中文翻译：

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火山成因硫酸盐驱动的冷却事件的陆地证据 在白垩纪-古近纪大灭绝前 ~30 kyr


除了 Chicxulub 陨石撞击外，德干火山活动被认为是白垩纪-古近纪 （K-Pg） 大灭绝的主要触发因素。模型表明，碳和硫的火山脱气（强大的环境压力源）推动了全球温度变化，但这种变化的相对时间、持续时间和幅度仍不确定。在这里，我们使用有机古温度计 MBT′ 5me 和来自美国西部的两个跨越 K-Pg 的褐煤的碳同位素组成，来测试大灭绝前~100 kyr 中火山成因空气温度变化的模型。我们的记录显示，长期变暖 ~3°C，可能是由德干 CO 2 排放驱动的，并揭示了瞬态 （<10 kyr） ~5°C 的冷却事件，与德干喷发的 Poladpur “脉冲” 峰值相吻合，在 K-Pg 边界之前 ~30 kyr。这种冷却可能是由火山硫的气溶胶引起的。温度恢复到大灭绝前的事件前值，这表明从陆地的角度来看，火山气候变化并不是 K-Pg 灭绝的主要原因。