The geothermal field at Krafla, Iceland, where a borehole being drilled for a geothermal energy research project hit molten rock at 6,900 feet

"This is only the third time that magma has ever flowed into a
geothermal drill hole, as far as we know," said Peter Schiffman, a
geology professor at UC Davis and member of the international team
conducting the study. "A research project in Hawaii hit magma in 2005,
and in 1977 magma erupted out the top of a producing geothermal well
not far from our site in Krafla, Iceland."

In Hawaii, drilling stopped. And Schiffman is doubtful that this
project, known as the Iceland Deep Drilling Project, or IDDP, can
continue. But if the magma body is narrow — as he and the research
team expect it is — it may be possible to bore through it or around
it, he said. "We've been able to keep circulation of cold water
through the drill string, so our equipment is still functional."

The team had originally planned to drill to 11,500 feet, or almost 2.2
miles into the earth.

The main purpose of IDDP — an international research effort supported
by the National Science Foundation, the International Continental
Drilling Program, Alcoa Inc., and Icelandic power companies — is to
investigate the economic feasibility of extracting energy from
hydrothermal systems that are under extremely high temperatures and
pressures.

Drilling began at the site near Krafla in northeast Iceland in
December 2008. After reaching a depth of 2,600 feet, the project was
put on hold for two months before resuming in early March.

Around the middle of April, Schiffman said, drilling became difficult.
"We kept drilling, but had lots of technical problems. We just seemed
to be stuck at the same depth," he said. "Just yesterday we realized
that we had run into magma."

Schiffman is receiving updates from his UC Davis colleagues who are
onsite in Iceland: geology professor Robert Zierenberg and graduate
student Naomi Marks. The pair reported that a phenomenon known as
"steam flashing" seems to have occurred on Thursday (June 25), when
drilling fluid came in contact with magma, creating an explosion.
Glass shards removed from the hole provided evidence for this,
Schiffman said. These most likely formed when the fluid, which is
principally water, quenched molten rock.

Based on geophysical mapping of the area, Schiffman said, the team
suspects that it has encountered a small offshoot of a larger magma
body that lies more than two miles below the surface. "Whether we can
keep drilling or not will depend on the thickness of this magma
finger, and whether it's horizontally or vertically oriented," he
said.

If the hole cannot be drilled any deeper, it might prove useful for
testing a system of geothermal energy extraction that involves sending
cold water into one borehole to be retrieved as superheated steam from
deeper holes nearby, Schiffman said.