The Iceland Deep Drilling Project (IDDP) will study the interaction of high-temperature (~ 450oC) hydrothermal fluids with oceanic crust on the Reykjanes Peninsula, at the southwestern tip of Iceland, where the Mid-Atlantic Ridge emerges from the ocean. The requested funds would be highly leveraged because most of the cost of drilling a 5km deep borehole will be borne by industry and the Icelandic government, with participation from the International Continental Scientific Drilling Program. An Icelandic geothermal power company is providing an existing ~ 3 km deep well for deepening to 5 km depth. This project will provide the first opportunity worldwide to investigate the deep, high temperature reaction zone of a mid-ocean ridge hydrothermal system, which has been a long-standing goal of the Ocean Drilling Program. This drill site is ideally situated for a broad array of scientific studies involving reactions between basalt and seawater at high temperatures, reaching supercritical conditions. Such active processes in the deep, high temperature reaction zones that control fluid compositions of black smokers have never before been available for comprehensive direct study and sampling. Ocean drilling has penetrated only 2 km into 5 Ma old ocean crust. where temperatures were ~ 180 oC. In contrast, the IDDP collaboration with industry in Iceland will produce fluid samples from the flow tests at 3, 4, and 5 km, drill cuttings and spot cores down to 4.0 km depth, and 1.0 km of continuous drill core from 4.0 to 5.0 km depth. These samples will reveal the integrated record of basalt-seawater interactions at >400oC. The study of these materials will permit a quantum leap in our understanding of active hydrothermal processes that are important on a global scale,
The funds provided will be used for: (1) coring for scientific purposes; (2) support for the scientific program at the well site, for fluid sampling, for core handling, and for basic petrologic characterization of the cores, and distribution of sub-samples and data to an approved list of international scientists; and (3) support for a coordinated group of US Co-PI's investigating hydrothermal water/rock interactions and geochemical modeling. The core and fluids that will be retrieved may characterize the lower boundary of a major hydrothermal system and thus provide important evidence about what controls the upper temperature limits of hydrothermal systems.
The Iceland Deep Drilling Project (IDDP) is an internal research collaboration exploring the potential to find, evaluate, and produce unconventional geothermal energy resources by drilling to depths of 4-5 km in active geothermal fields in Iceland. The goal is to reach conditions pressure and temperature conditions where supercritical fluids are present (Temperatures greater than 374° C at pressures greater than 221 bars for pure water). A single well producing supercritical fluid at the same rate as a conventional geothermal well could provide 5-10 times the amount of energy. Geothermal energy has very low carbon emissions and contributes to base-load electrical demand, in contrast to other sustainable energy sources. The research supported by this NSF grant allowed us to investigate how water and volcanic rock interact at high temperatures deep within geothermal fields. Our research has documented that very high temperature (>600° C) are recorded by hydrothermal minerals occurring in the subsurface of the Reykjanes geothermal field in southern Iceland, and that this geothermal system shares many geochemical similarities to the "black smoker" seafloor hydrothermal systems that occur on mid-ocean ridge seafloor spreading centers. A hole intended for deep drilling at the Krafla geothermal field in northern Iceland unexpectedly drilled into molten rock (magma) at a depth of about 2 kilometers. The material recovered from this drill hole has provided an extraordinary opportunity to investigate high temperature igneous, metamorphic and hydrothermal processes at the edge of a magma body. The well is currently being evaluated for its potential to produce geothermal electricity. The well is presently discharging substantial amounts of superheated steam at temperatures that exceed 420° C, and it has the potential to be one of the world’s most powerful geothermal wells, and the first well that could be designed to produce geothermal energy by direct interaction of water with a crystallizing magma body. Further information, including video clips of the steam discharged from the well, can be obtained at the IDDP website http://iddp.is/
