News Archive

posted 09/09/04

Geologist Ascends Peaks and Dives to the Ocean Floor, Looking for Secrets of Earth's Crust

Peter Kelemen in East Greenland

Peter Kelemen, who was recently appointed Arthur Storke Memorial Professor of Geochemistry in the Department of Earth and Environmental Sciences at Columbia University, shown here in East Greenland, 2000, scoping out the East Face of Ejnar Mikkelsen's Fjeld.

Says Keleman of this photo, "This mountain is composed of 'flood basalt' lava flows, which erupted to form a seven-kilometer-thick pile of volcanic rocks in less than one million years, about 56 million years ago, just before the opening of the North Atlantic. Supported by the Danish Lithosphere Centre, Stefan Bernstein (now at the Greenland Geological Survey) and I camped here, 50 km from the coast and a much longer way to the nearest other person, for ten days in the summer of 2000.

"In 1995, Stefan and I had found fragments of the Earth's upper mantle, dating to about 3 billion years ago, that were carried to the surface in a dike-feeding lava flows. These are the only mantle samples from East Greenland, and among very few examples of mantle from the ancient Greenland craton, which contains the oldest rocks on Earth.

"We projected the trend of dikes that hosted mantle fragments inland, and chose this place to look for more fragments five years later, travelling on skis along the edge of the huge Kronborg Glacier. And we found more mantle samples!" Photo by Stefan Bernstein

As a geologist, Peter Kelemen has ascended to 7,500 meters on a Himalayan peak and plummeted into the Atlantic to 5,500 meters. From 1981 to 1991, he worked as a consultant on mineral exploration projects where the terrain was too steep for average geologists. He has traveled via snowmobile, helicopter and climbing rope, all in the pursuit of secrets of the Earth's crust.

In the Himalayas, he studied the process of mountain building at the collision of India and Asia, where the enormous peak of Gasherbrum IV rises up 8,000 meters — a perfect location to study a vast range of elevations. He has also done research in Oman, where a block of the Earth's crust (called an "ophiolite") the size of Massachusetts has been thrust up on land. Says Kelemen, who was recently appointed the Arthur Storke Memorial Professor of Geochemistry in the Department of Earth and Environmental Sciences, "The Oman ophiolite offers a view of the internal geometry of oceanic plates that is unmatched by any sampling or imaging technique at sea."

The melt flow beneath volcanoes —"the plumbing systems of volcanoes," as Kelemen puts it — is another area of study for him. Because melt is highly reactive, focused melt migration leaves visible traces. Studying this process provides clues to how reactive porous flow of other substances, for example in oil fields, might be organized. Kelemen plans someday to extend his studies to fluid migration within glaciers. "With glaciers the drainage morphology is very similar to that in the mantle beneath volcanoes," he says. "The benefit is we can study an active system versus what may have happened hundreds of millions of years ago in the upper mantle. There is lot of fairly basic physics in melt migration that is analogous to other kinds of fluid migration."

“By studying melt migration processes,” Kelemen says, “scientists can learn how geological systems organize themselves. It also may provide answers to how much energy is emitted from the Earth's interior to the hydrosphere, and what the spatial distribution of that energy emission is — subjects of much debate among scientists.”

For summer 2005, Kelemen, through funding from the National Science Foundation, has planned a research trip to the western end of the Aleutian volcanic chain, an area he has studied for ten years but has never visited. There, in the 1960's, a lava sample was recovered from the seafloor that has a very similar composition to the ancient continental crust. Kelemen plans to obtain more of these samples by examining the catch from a metal bag about ten feet in diameter that will be dragged along the flanks of submarine volcanoes on the seafloor. He hopes his research will provide information on how the continental crust was formed.

Kelemen and his colleagues Dave Scholl and Gene Yogodzinsk also plan to create a more accurate bathymetric map. "There are probably hundreds of volcanoes in that area that don't exist on maps," he says. "An active volcano in the western Aleutians that comes within 115 meters of the ocean surface was just discovered and mapped in 2002-2003." (The mapping was directed by Jennifer Reynolds, a Lamont-Doherty Earth Observatory alumnus; more information is at http://www.sfos.uaf.edu/news/2003/0811volcano.html.)

Peter Kelemen

Peter Kelemen

Kelemen, who came to Columbia University after 15 years at the Woods Hole Oceanographic Institution, joined the Lamont-Doherty Earth Observatory and DEES this summer. This past spring, he was elected a Fellow of the American Geophysical Union. In addition to his research, Kelemen is co-teaching Introduction to Earth Sciences 1 with John Mutter, Deputy Director of the Earth Institute, who has taught the class for the past 10 years.

Last fall, Kelemen and his colleague Greg Hirth in Woods Hole initiated an unusual new field course for graduate students. They spent 10 days at sites where the Earth's mantle has been thrust up on land and exposed. During this project-oriented graduate field class, students mapped and sampled a small area, and then Kelemen expedited sample analyses, allowing students to spend the semester learning techniques and interpreting their results for a final project. Last fall, Kelemen took students to northern California, though the locations vary.

As for exploring rocks more than 5,000 meters below sea level in a submersible, Keleman says, "The viewing window is so small. I'd rather combine sea-going observations with field work someplace where I can actually see the rocks."

More information about Peter Keleman's research: http://eesc.columbia.edu/faculty/kelemen.html and also at http://science.whoi.edu/labs/mclean210/kelemen/index.html

The Lamont-Doherty Earth Observatory, a member of the Earth Institute at Columbia University, is one of the world's leading research centers examining the planet from its core to its atmosphere, across every continent and every ocean. From global climate change to earthquakes, volcanoes, environmental hazards and beyond, Observatory scientists provide the basic knowledge of Earth systems needed to inform the future health and habitability of our planet.

The Earth Institute at Columbia University is among the world's leading academic centers for the integrated study of Earth, its environment, and society. The Earth Institute builds upon excellence in the core disciplines—earth sciences, biological sciences, engineering sciences, social sciences and health sciences—and stresses cross-disciplinary approaches to complex problems. Through its research, training and global partnerships, it mobilizes science and technology to advance sustainable development, while placing special emphasis on the needs of the world's poor.