(Table T1) Cation exchange capacities and contribution of cations to CEC in sediments from ODP Leg 168 sites@en

Fluid circulation at midocean ridge flank areas where the igneous crust is young and still hot and sediment cover is usually thin actually produces a major chemical exchange between the ocean and the crust, although temperatures and rates of fluid flow are low (Mottl and Wheat, 1994, doi:10.1016/0016-7037(94)90007-8). The primary objectives of Ocean Drilling Program Leg 168 were to elucidate the mechanism driving flow through the crust and seafloor, the magnitude of elemental chemical exchange between the crust and ocean, and the factors controlling the chemistry of fluids circulating in ridge flanks covered by sediments (Shipboard Scientific Party, 1997, doi:10.2973/odp.proc.ir.168.101.1997). To this purpose, Leg 168 drilled a series of holes in the eastern flank of the Juan de Fuca Ridge along a transect from Site 1023, a transition site from crust without sediment cover, to Site 1027, a site with sediment cover that is about 100 km east of the ridge axis. My research objective on the cruise was to understand the role of sediments in controlling the chemistry of circulating fluid. […]