Paper No. 68-3
Presentation Time: 2:10 PM
THE EFFECTS OF LARGE IGNEOUS PROVINCES ON THE GLOBAL CARBON AND SULPHUR CYCLES: UNDERSTANDING THE SOURCES, THE SINKS AND ERUPTION STYLES
The correlation between Large Igneous Province (LIPs) and extinction events suggests that volcanism can have a detrimental impact on Earth surface conditions. Changes in atmospheric and ocean chemistry, particularly the climate-sensitive carbon and sulphur cycles, are the most probable method of inducing global ecosystem stresses. However, the interactions and feedbacks between volcanism and these cycles are numerous and complex, making analyses and characterising the response to a LIP problematic. Additionally the eruption mechanisms of the volcanic system are also poorly understood, particularly how they might transfer gases into the atmosphere. Here we summarise the sources and sinks of carbon and sulphur from large volcanic eruptions using information from modern and ancient systems. For the sources, we summarise the current understanding of volcanic emissions, and explore the relative contributions and importance of magma-derived degassing versus secondary degassing from sediments affected by magmatic intrusions and lava. In addition, we will explore the various ways in which LIPs can reduce atmospheric concentrations of these same elements. The relative contributions of each source and sink are in part determined by the mode of LIP emplacement and eruption style, along with the subsequent timescales of such effects. Therefore, we explore a few key examples with recent data to demonstrate how the environmental impact can vary considerably with differing modes of emplacement, LIP duration and eruption styles.