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FRINATEK-Fri mat.,naturv.,tek

End-Permian environmental changes and the Siberian Traps volcanism (EPIC, Svensen)

Awarded: NOK 8.2 mill.

The Large igneous province in Siberia, the so-called Siberian Traps, erupted 252 million years ago. At the same time, a large part of life on Earth got extinct. The key scientific hypothesis to explain the extinction is the release of gases from the shallow crust in Siberia. We have studied pipe-like explosions structures in Siberia, believed to be responsible for the gas release. Two detailed studies are targeted at the pipes and their related crater lakes. It turned out that the craters are full of organic material and sulphur. These compounds can tell us about what happened 252 million years ago. Sulphur and carbon-gases were released through the pipes and to the atmosphere. Pollen and other organic remains were trapped in the crater sediments, making this geological system a unique archive of one of the most dramatic time periods in Earth?s history. We have identified hundreds of pipes in Siberia, supporting a causal relationship between the large scale volcanic activity and the environmental disaster. We have also studied the processes behand the gas generation. The gases formed around igneous sill intrusions within the salt-rich strata of East Siberia. We have quantified the degassing from this system, and conclude that even single volcanic events had the potential to cause global warming on a century scale. Our project results stress the importance of sub-volcanic processes in triggering rapid environmental changes.

The geological record shows that the Earth suffered severe environmental crises, including the end-Permian (~252 million years ago; Ma) and end-Triassic (~200 Ma) mass extinctions, when species in the ocean and on the continents got extinct. Despite being subjected to intense focus from a number of research groups worldwide, there is still not much consensus about what triggered these boundary events and other major crises in the history of the Earth. In 2004 I published a paper in Nature suggesting that the end-Permian and end-Triassic crises could be caused by carbon degassing from organic-rich sedimentary basins heated by hot magmatic intrusions related to Large Igneous Provinces (LIPs). This paper is widely cited (~180 ISI-citations), and the hy pothesis has been extended to other boundary events and is currently explored by other groups. With this ERC grant I would like to move the research in a new direction and build a world-leading group devoted to past crises. This agenda is rooted in using the prime example, the Siberian Traps and the end-Permian event, as the main case and where the research is driven by a set of new key findings. These findings include the discovery of thermally affected oil in a number of lava flows in the Siberian Traps LIP (important for the volume and speciation of the emitted gases), huge areas in Siberia where tuffs are lacking (showing less explosive activity than previously believed), and the discovery of sedimentary rocks in East Siberia where the transition from background sediments to volcaniclastic sediments to lava flows is exposed (unique possibility to obtain near-field proxy data.

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FRINATEK-Fri mat.,naturv.,tek