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Precious rare earth metals discovered where continental plates collided

New finding indicates that rare earth elements used in technologies from smartphones to wind turbines may exist in previously unexplored locations where mountains were built by collisions rather than where continental plates separated. 

Ker Than
November 5, 2013

A rare trove of precious metals discovered beneath a desolate stretch of ice-shrouded coastline in Greenland is providing valuable clues about the geological processes that help concentrate so-called rare earth elements, according to new research from Stanford.

Rare earth elements, or REEs, are a set of seventeen chemically related heavy metals that are essential components of many modern technologies, including smartphones, flat screen televisions, electric vehicles, energy-efficient lighting and wind turbines.

The newfound REE deposit, discovered by Stanford Geological & Environmental Sciences Professor Dennis Bird, is located in the Karrat Isfjord region of west Greenland. The highly sought after metals are embedded in a band of rock measuring about 4 miles (7 kilometers) long and at least 100 feet (30 meters) wide. The full depth of the deposit has not yet been determined, as it extends beyond the range of current exploratory drilling.

Andrew Mott, a doctoral student in Bird's lab, conducted laboratory studies of the samples and concluded that the Karrat deposit formed some 1.8 billion years ago during the collision of two continental plates. That's different from other rare Earth deposits known around the world, which scientists think largely formed from continental plate separation, or "rifting" events. The finding appeared in the October 23 issue of the Journal of Economic Geology.

"Andrew's work has dated this mineralization to a time that correlates with a continental collision like that which formed the Himalayas," Bird said. "This was not the tectonic environment in which we expected to find rare earth deposits." 

The surprise discovery may mean that rare earth deposits are lurking in previously unexplored settings, namely those associated with collisional mountain-building events, said study coauthor Marty Grove, a professor (research) in the Stanford Department of Geological & Environmental Sciences. "It probably means that there is the potential for rare earth deposits in many places where we currently don't look," Grove said. 

Image courtesy of Dennis Bird.
Stanford professor Dennis Bird (left) and alum Nicholas Rose (Geology, PhD, 1989) pose for a photograph atop a newly discovered deposit of rare earth minerals in west Greenland that is providing clues about how the precious metals form.