EAPSI:Resolving sources of volcanic and hydrothermal gases from the North Island of New Zealand

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While volatile elements like carbon are returned to the deep Earth at convergent tectonic margins like the Hikurangi Margin off the coast of New Zealand?s North Island, some carbon in marine sediments is released through volcanic and hydrothermal activity. Geologic cycling of carbon ? both at settings like the Hikurangi Margin and globally ? is poorly understood and must be clarified to evaluate anthropogenic effects on the carbon budget. This award supports the first concerted volatile sampling and analysis campaign aimed at elucidating where, relative to the Hikurangi Trench, slab-derived C is first detected in geothermal systems and how the extent of C release changes with distance from the trench. Field sampling and analysis will be conducted in collaboration with Dr. Bruce Christenson of GNS Science, New Zealand.In addition to the overall carbon cycling budget, the sampling that will be conducted in the fore-arc, volcanic center (the Taupo Volcanic Zone), and back-arc regions of the North Island will be used to constrain cycling and devolatilization potential of various carbon, nitrogen, and helium reservoirs at different depths along the subducting slab. Fore- and back-arc devolatilization processes are poorly understood, as are the particular geochemical reactions responsible for volatile release and the potential for carbonate in altered oceanic crust to contribute to carbon fluxes. New volcanic, hydrothermal, and rock samples will enable more complete thermodynamic modeling of subduction zones, with local as well as global implications. Comprehensive sampling and analysis will also permit refinement of standard models used to distinguish sources of volatiles released at subduction zones. This award is funded in collaboration with the Royal Society of New Zealand.