Intellectual Merit: This proposal is to conduct a number of hydrogeologic experiments in ocean crust on the east flank of the Juan de Fuca Ridge in the Northeast Pacific Ocean. The aim of the experiments is to study the movement of fluids, chemicals and microbes within the ocean crust between drill holes completed by the Integrative Ocean Drilling Program. The work will be the first to run a long-term cross-drill-hole test in the ocean crust. One and two years following the Integrative Ocean Drilling Program expedition in 2010, the down hole instruments will be serviced and samples collected from multiple depths in the hole. Three-dimensional numerical modeling will evaluate how flow works within the oceanic crust. Taken together, the proposed work will constrain heat transport, chemical transport, and sub-seafloor microbiology making the results of value to many communities. Broader Impacts: This project will train graduate and undergraduate students and will leverage off of an existing education and outreach program already in place for the Integrative Ocean Drilling Program expedition in 2010.
Many homes within the US get their water from subsurface aquifers. Boreholes are drilled into the sediment and rock. They end within a permeable zone, the aquifer. The boreholes are then cased to prevent sediment and rock from sealing the borehole. After completion boreholes undergo a variety of tests to determine the size of the aquifer and the rate at which the aquifer can recharge. This determines how much water can be pumped out of the aquifer for human use. A neighborhood of 30 houses typically ahs 3 such borehole or "wells". There are millions of such wells on the continent and only a handful of wells in the ocean. This award focused on sampling a handful of boreholes within a kilometer of each other that were drilled through the sediment and into basalt 2660 m below sea-level. Testing included the introduction of chemical tracers within one of the boreholes to assess if the other boreholes were interconnected. Many boreholes on land are not connected, even when spaced tens of meters apart. Results from sampling these boreholes using undersea remotely operated vehicles (ROVs) indicate that each of the boreholes is hydrologically connected. This is a significant result because it means that much of the upper oceanic basaltic crust is hydrological interconnected and possibly suitable for future carbon sequestration as it provides a vast potential reservoir for the placement of this carbon.
