Deep Drilling for

A hydrothermal vent chimney on the East Pacific Rise in the eastern Pacific Ocean. Vents like these exist at mid-ocean ridges on the ocean floor around the world and support many unique forms of life.
Credit: Woods Hole Oceanographic Institution

A project to learn more about extracting energy from hot rocks on land should give clues about "black smokers," hydrothermal vents that belch superheated water and minerals deep below the ocean.

As part of the Iceland Deep Drilling Project, researchers from UC Davis, UC Riverside, Stanford University and the University of Oregon plan to sink a deep borehole into a site on land where seawater circulates through deep, hot rock. Most such sites on land have circulating fresh water, with very different chemistry.

"It’s the dry land version of a deep sea hydrothermal vent," said Robert Zierenberg, professor of geology at UC Davis. Zierenberg and another geology professor, Peter Schiffman, are the UC Davis members of the research team. "It’s the first opportunity to look at rocks and fluid together and in situ."

Deep ocean hydrothermal vents support unique communities of living things that, unlike most ecosystems on Earth, draw no energy from the sun. These vents also generate unusual, and possibly valuable, deposits of copper, zinc and other minerals.

Astrobiologists study organisms around hydrothermal vents on Earth in order to understand how life might survive in oceans on other celestial bodies, such as Europa. Scientists hypothesize that Jupiter’s moon Europa contains a liquid ocean beneath its icy crust. If hydrothermal vents are present in this ocean, they could provide an energy source for living organisms similar to those seen around hydrothermal vents on Earth.

The island nation of Iceland, in the north Atlantic, is famous as a hotspot for geothermal activity. Although located in chilly northern climes, the land is peppered with active geysers and volcanoes.
Credit: NASA

Zierenberg said it is technically challenging to drill into rocks that are under high pressure and bathed in corrosive fluids at 450 degrees Celsius (840 degrees Fahrenheit), but it is easier than trying to drill deep below the sea floor in the deepest parts of the ocean.

The Iceland Deep Drilling Project is supported by the Icelandic power industry and government, in collaboration with U.S. government agencies. It aims to drill deep boreholes to learn more about processes in deep, hot rocks, with the goal of producing more energy from a single geothermal well. Iceland already gets half of its electrical power and meets much of its needs for space heating and hot water from geothermal energy.

The university research project is supported by grants from the National Science Foundation and the International Continental Drilling Program. The researchers expect to start drilling in the summer of 2008.

 

Artists conception of a possible liquid ocean beneath Europa’s surface. Terrestrial extremophile bacteria possibly could live in this ocean.
Credit: NASA

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