Fluorine in sediments and porewaters in the subduction zone offshore Costa Rica, ODP Leg 170

Abstract

The results presented here are based on samples collected by the author during ODP Leg 170, 16.October - 17.December 1996, and subsequent analyses at the laboratories of the Geological Survey of Norway, Trondheim, Norway. The main objectives for thoroughly documenting the chemistry of the pore fluids and solids are: 1) to identify the distribution of key elements and isotope ratios between pore fluids and various solid phases 2) to quantify the fluxes of these key elements and isotopes into the sub- duction zone 3) to utilize these data for evaluating geochemical and material mass balance as well as constraining the importance of underplating (Kimura et al. 1997, p.74) Ultimately it is the concentration data of the key elements in the sediments and the pore fluids which are necessary for answering the question how much material is subducted. Fluorine in pore fluids and in solids is one of the key elements in this setting.