Volatiles and Fluids in Subduction Zones

Overview Theme C5

Project C5 comprises two modelling packages. Package I involves the modelling of climate effects of arc-volcano volatile discharges and possible climate feedbacks with the geo- and hydrosphere. Package II is on the modelling of volatile transfer through subduction zones and its role in global element cycles, which provides a physical synthesis of the volatile budgets empirically derived in other SFB 574 projects.

Package I: Investigating climate feedbacks is a central research task of the SFB 574. Volcanic eruptions play a significant role on the global climate of the Earth system and can delay and damp the global warming due to anthropogenic climate change. Major volcanic eruptions, which directly inject material into the stratosphere, have a strong and long lasting impact on the global climate depending on their geographical latitude and their SO2 release. We will use state of the art climate models to study the climate effects and feedbacks of past Central and South American major volcanic eruptions analysed within the SFB 574. Simulations with different complexity of climate models enable us to assess their effect on the paleo and present day climate but also to hypothesize their effect in a future climate scenario. Special emphasis will be placed on the global role of volcanic released halogen species on atmospheric chemistry and the possibility of a volcanic induced pre-industrial Ozone hole. The role of the ocean interacting with the atmosphere during a major volcanic eruption is an important climate feedback (e.g. ENSO, ocean heat content and sea level response), which will be investigated in more detail.

Package II addresses the cycling of volatiles through subduction zones. The key objective is to develop numerical models that link subduction input to output. During the first and second phase of the SFB 574, we have developed numerical models for simulating water cycling in subduction zones. During the third phase, we will extend and improve these tools to include other volatiles like CO2. Furthermore, the existing 2-D tools will be made three-dimensional. 3-D simulations of mantle flow beneath the Central American and Chilean subduction zones will provide better insights into volatile transfer from the slab to the arc volcanoes. These new and improved models will also help to better link subduction input to output and to integrate the different data sets gathered in the various SFB 574 projects.