Figure 3.
Schematic (not to scale) of borehole locations and experimental design for a tracer injection experiment conducted during and after Expedition 327 to investigate transport rates in the upper ocean crust. Boreholes observatories were placed in ~3.5–3.6-m.y.-old crust on the eastern flank of the Juan de Fuca Ridge. Thicker sections of the drill pipe indicate open intervals where tracer was injected or sampled. The stratigraphy of the upper volcanic crust at Hole U1301B is shown on the left. Main diagram modified from Fisher et al. (2011), and stratigraphic column is from Becker et al. (2013). Experimental results indicate very rapid tracer transport (meters/day), with most of the flow occurring in a small fraction of the rock (Neira et al., 2016). See Figure S7 for additional information (see text footnote 1).