Posts Tagged ‘Stanford University’

Russian site could be late Neanderthal refuge

May 24, 2011
By MALCOLM RITTER, Associated Press 05/19/2011 Original article here

NEW YORK — Scientists have identified what may be one of the last northern refuges of Neanderthals, a spot near the Arctic Circle in Russia with artifacts dated to 31,000 to 34,000 years ago.

Stone tools and flakes found there look like the work of Neanderthals, the stocky, muscular hunters who lived in Europe and western Asia until they were replaced by modern humans, researchers reported today in the journal Science.

The site lies along the Pechora River west of the Ural Mountains, about 92 miles south of the Arctic Circle. Researchers dated it from animal bones and sand grains. Nobody has found any human bones or DNA that could provide stronger evidence that Neanderthals lived there, report the scientists, from Russia, France and Norway. The artifacts had been collected during various expeditions.

Richard Klein, a Stanford University professor of anthropology, said the artifacts do look like the work of Neanderthals, but that it’s also possible they were made by modern people instead.

Neanderthals were not previously known to be in that area, nor convincingly shown to be present anywhere at such a recent time, he said. Finding another site or human bones would help settle the question, he said.

Eric Delson, a paleoanthropologist at Lehman College of the City of New York, cited a 2006 study that suggests Neanderthals occupied a cave near the southern tip of Spain at about the same time as the new work puts them in Russia. Maybe the two locations show how Neanderthals retreated in opposite directions from the encroachment of the modern humans, he said.

Iceland Volcano Drilling Suggests Magma Could Become Source of High-Grade Energy

February 17, 2011

This is a view of the Krafla volcano, Iceland, across the explosion crater Viti that erupted in 1787, showing the drilling rig. The borehole encountered molten rock at 6,500 feet depth. (Credit: G.O. Fridleifsson.)

ScienceDaily (Feb. 16, 2011) Original article here

Geologists drilling an exploratory geothermal well in 2009 in the Krafla volcano in Iceland encountered a problem they were simply unprepared for: magma (molten rock or lava underground) which flowed unexpectedly into the well at 2.1 kilometers (6,900 ft) depth, forcing the researchers to terminate the drilling.

“To the best of our knowledge, only one previous instance of magma flowing into a geothermal well while drilling has been documented,” said Wilfred Elders, a professor emeritus of geology in the Department of Earth Sciences at the University of California, Riverside, who led the research team. “We were drilling a well that was designed to search for very deep — 4.5 kilometers (15,000 feet) — geothermal resources in the volcano. While the magma flow interrupted our project, it gave us a unique opportunity to study the magma and test a very hot geothermal system as an energy source.”

Currently, a third of the electric power and 95 percent of home heating in Iceland is produced from steam and hot water that occurs naturally in volcanic rocks.

“The economics of generating electric power from such geothermal steam improves the higher its temperature and pressure,” Elders explained. “As you drill deeper into a hot zone the temperature and pressure rise, so it should be possible to reach an environment where a denser fluid with very high heat content, but also with unusually low viscosity occurs, so-called ‘supercritical water.’ Although such supercritical water is used in large coal-fired electric power plants, no one had tried to use supercritical water that should occur naturally in the deeper zones of geothermal areas.”

Elders and colleagues report in the March issue of Geology (the research paper was published online on Feb. 3) that although the Krafla volcano, like all other volcanoes in Iceland, is basaltic (a volcanic rock containing 45-50 percent silica), the magma they encountered is a rhyolite (a volcanic rock containing 65-70 percent silica).

“Our analyses show that this magma formed by partial melting of certain basalts within the Krafla volcano,” Elders said. “The occurrence of minor amounts of rhyolite in some basalt volcanoes has always been something of a puzzle. It had been inferred that some unknown process in the source area of magmas, in the mantle deep below the crust of the Earth, allows some silica-rich rhyolite melt to form in addition to the dominant silica-poor basalt magma.”

Elders explained that in geothermal systems water reacts with and alters the composition of the rocks, a process termed “hydrothermal alteration.” “Our research shows that the rhyolite formed when a mantle-derived basaltic magma encountered hydrothermally altered basalt, and partially melted and assimilated that rock,” he said.

Elders and his team studied the well within the Krafla caldera as part of the Iceland Deep Drilling Project, an industry-government consortium, to test whether geothermal fluids at supercritical pressures and temperatures could be exploited as sources of power. Elders’s research team received support of $3.5 million from the National Science Foundation and $1.5 million from the International Continental Scientific Drilling Program.

In the spring of 2009 Elders and his colleagues progressed normally with drilling the well to 2 kilometers (6,600 feet) depth. In the next 100 meters (330 feet), however, multiple acute drilling problems occurred. In June 2009, the drillers determined that at 2104 meters (6,900 feet) depth, the rate of penetration suddenly increased and the torque on the drilling assembly increased, halting its rotation. When the drill string was pulled up more than 10 meters (33 feet) and lowered again, the drill bit became stuck at 2095 meters (6,875 feet). An intrusion of magma had filled the lowest 9 meters (30 feet) of the open borehole. The team terminated the drilling and completed the hole as a production well.

“When the well was tested, high pressure dry steam flowed to the surface with a temperature of 400 Celsius or 750 Fahrenheit, coming from a depth shallower than the magma,” Elders said. “We estimated that this steam could generate 25 megawatts of electricity if passed through a suitable turbine, which is enough electricity to power 25,000 to 30,000 homes. What makes this well an attractive source of energy is that typical high-temperature geothermal wells produce only 5 to 8 megawatts of electricity from 300 Celsius or 570 Fahrenheit wet steam.”

Elders believes it should be possible to find reasonably shallow bodies of magma, elsewhere in Iceland and the world, wherever young volcanic rocks occur.

“In the future these could become attractive sources of high-grade energy,” said Elders, who got involved in the project in 2000 when a group of Icelandic engineers and scientists invited him to join them to explore concepts of developing geothermal energy.

The Iceland Deep Drilling Project has not abandoned the search for supercritical geothermal resources. The project plans to drill a second deep hole in southwest Iceland in 2013.

Elders was joined in the research project by researchers at HS Orka hf (HS Power Co.), Iceland; UC Davis; Stanford University; Iceland GeoSurvey; Landsvirkjun Power, Iceland; the U.S. Geological Survey; New Mexico Institute of Mining and Technology; and the University of Oregon, Eugene.