What goes in must come out?

What is the fate of the volatiles that are stored in trench sediments, igneous crust and hydrated lithospheric mantle and that are transported into a subduction zone? G&G Marie Curie Research Fellow Jacob Geersen has been involved in recently published research, that constrains and compare the input and output fluxes of water, chlorine and sulfur into the Central Chilean subduction zone. Results suggest that ~30% of the input volatiles are cycled back into the ocean through the forearc whereas the volcanic output accounts for 3% of the input. The largest part of the volatiles that are carried into the subduction zone (two-thirds of the input) seems to be transported beyond the volcanic arc. The derived numbers are in good agreement with previous studies that determined the volatile output of other subduction zones, such as Central America or Kamchatka. The fact that the individual studies, all based on variably comprehensive data sets and following different approaches, generate similar results suggesting that neither the geotectonic setting nor the input parameter has significant influence on the volatile output fluxes of entire subduction zones.

Read the full paper here.