Investigatigating the spatio-temporal evolution of the slab-derived fluids using micro-analytical techniques.
During subduction, the downgoing plate (slab) progressively dehydrates and releases its fluids into the surrounding mantle wedge. Fluids released from the downgoing plate play a key role in subduction processes. They serpentinize the cold forearc mantle at shallow depths (< 100 km slab depth). Deeper, they trigger hydrous mantle melting beneath the arc volcanoes and sometimes at backarc basin spreading center. Thus, the downgoing plate transfers some of its chemical imprint to the lavas.
The downgoing plate releases its fluids into the mantle wedge as subduction proceeds. The slab-derived fluid is water-rich beneath the forearc (1), and progressively becomes less aqueous (2). With increasing depth the slab can start melting and releases solute-rich (< 20% H2O) to supercritical fluids (3).
Because the slab progressively loses its water and other volatiles during subduction, the composition of the fluids varies with increasing slab depth (i.e., across the arc) and with time. My goal is to investigate the temporal and spatial evolution of the subduction outfluxes. For this, I examine the composition of melt inclusions hosted by crystals, as they may capture a reliable composition of the fluids. I also investigate the nature of the reservoirs (atmosphere, hydrosphere, mantle, crust) of the volatiles and their chemical exchanges.
Ribeiro J.M., Stern R.J., Shaw A., Kelley K.A., Martinez F., Ohara Y. (2015) Composition of the slab-derived fluids released beneath the Mariana forearc: evidence for shallow dehydration of the subducting plate. Earth and Planetary Science Letters, doi: 10.1016/j.epsl.2015.02.018.
Ribeiro J.M., Stern R.J., Kelley K.A., Shaw A., Martinez F., Ohara Y. (2014) Evidence for shallow dehydration of the subducting plate beneath the Mariana forearc: New insights into the water cycle at subduction zones, AGU Fall meeting 2014.
Ribeiro J.M. , Stern R.J., Kelley K., Shaw A., Shimizu N., Ishizuka O., Ishii T., Manton M. (2012) Nouveaux results from TN273 investigations in the SE Mariana forearc rift, AGU Fall meeting 2012.
Ribeiro J.M., Stern R.J., Kelley K.A., Martinez F., Ishizuka O., Manton W. (2013) Nature and distribution of the slab-derived fluids and mantle source along the Southeast Mariana Forearc Rift, Geochemistry Geophysics Geosystems, doi: 10.1002/ggge.20244.
Van Keken P. E., Hacker B., Syracuse E., Abers G.(2011) Subduction factory: 4. Depth-dependent flux of H2O from subducting slabs worldwide, Journal of Geophysical Research: Solid Earth, 116(B1), B01401, DOI: 01410.01029/02010jb007922.