Field evidence for coal combustion links the 252 Ma Siberian Traps with global carbon disruption

Abstract

The Permian-Triassic extinction was the most severe in Earth history. The Siberian Traps eruptions are strongly implicated in the global atmospheric changes that likely drove the extinction. A sharp negative carbon isotope excursion coincides within geochronological uncertainty with the oldest dated rocks from the Norilsk section of the Siberian flood basalts. We focused on the voluminous volcaniclastic rocks of the Siberian Traps, relatively unstudied as potential carriers of carbon-bearing gases. Over six field seasons we collected rocks from across the Siberian platform, and we show here the first direct evidence that the earliest eruptions in the southern part of the province burned large volumes of a combination of vegetation and coal. We demonstrate that the volume and composition of organic matter interacting with magmas may explain the global carbon isotope signal and may have significantly driven the extinction.